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1

GLAST Observatory Renamed for Fermi, Reveals Entire Gamma-Ray Sky |  

Broader source: Energy.gov (indexed) [DOE]

GLAST Observatory Renamed for Fermi, Reveals Entire Gamma-Ray Sky GLAST Observatory Renamed for Fermi, Reveals Entire Gamma-Ray Sky GLAST Observatory Renamed for Fermi, Reveals Entire Gamma-Ray Sky August 26, 2008 - 3:20pm Addthis WASHINGTON, D.C. - The U.S. Department of Energy (DOE) and NASA announced today that the Gamma-Ray Large Area Space Telescope (GLAST) has revealed its first all-sky map in gamma rays. The onboard Large Area Telescope's (LAT) all-sky image-which shows the glowing gas of the Milky Way, blinking pulsars and a flaring galaxy billions of light-years away-was created using only 95 hours of "first light" observations, compared with past missions which took years to produce a similar image. Scientists expect the telescope will discover many new pulsars in our own galaxy, reveal powerful

2

The Animated Gamma-ray Sky Revealed by the Fermi Gamma-ray Space Telescope  

ScienceCinema (OSTI)

The Fermi Gamma-ray Space Telescope has been observing the sky in gamma-rays since August 2008.  In addition to breakthrough capabilities in energy coverage (20 MeV-300 GeV) and angular resolution, the wide field of view of the Large Area Telescope enables observations of 20% of the sky at any instant, and of the whole sky every three hours. It has revealed a very animated sky with bright gamma-ray bursts flashing and vanishing in minutes, powerful active galactic nuclei flaring over hours and days, many pulsars twinkling in the Milky Way, and X-ray binaries shimmering along their orbit. Most of these variable sources had not been seen by the Fermi predecessor, EGRET, and the wealth of new data already brings important clues to the origin of the high-energy emission and particles powered by the compact objects. The telescope also brings crisp images of the bright gamma-ray emission produced by cosmic-ray interactions in the interstellar medium, thus allowing to measure the cosmic nuclei and electron spectra across the Galaxy, to weigh interstellar clouds, in particular in the dark-gas phase. The telescope sensitivity at high energy will soon provide useful constraints on dark-matter annihilations in a variety of environments. I will review the current results and future prospects of the Fermi mission.

Isabelle Grenier

2010-01-08T23:59:59.000Z

3

The Grapevine Expression Atlas Reveals a Deep Transcriptome Shift Driving the Entire Plant into a Maturation Program  

Science Journals Connector (OSTI)

...impact on ripe berry quality and the organoleptic properties of wine. Our gene expression...functional annotation to increase our knowledge of...that affect yield, quality, environmental responses...reveals expanded wine quality-related clades...

Marianna Fasoli; Silvia Dal Santo; Sara Zenoni; Giovanni Battista Tornielli; Lorenzo Farina; Anita Zamboni; Andrea Porceddu; Luca Venturini; Manuele Bicego; Vittorio Murino; Alberto Ferrarini; Massimo Delledonne; Mario Pezzotti

2012-09-04T23:59:59.000Z

4

Revealing the Superfluid Lambda Transition in the Universal Thermodynamics of a Unitary Fermi Gas  

E-Print Network [OSTI]

Fermi gases, collections of fermions such as neutrons and electrons, are found throughout nature, from solids to neutron stars. Interacting Fermi gases can form a superfluid or, for charged fermions, a superconductor. We ...

Ku, Mark Jen-Hao

5

Full Fermi Surface of a High Temperature Superconductor Revealed by Angular Magnetoresistance Oscillations  

Science Journals Connector (OSTI)

We report the first observation of polar angular magnetoresistance oscillations in the high-T c cuprate Tl2Ba2CuO6. These measurements establish the existence of a coherent three-dimensional Fermi s...

N. E. Hussey; M. Abdel-Jawad; A. Carrington…

2005-01-01T23:59:59.000Z

6

NEW FERMI-LAT EVENT RECONSTRUCTION REVEALS MORE HIGH-ENERGY GAMMA RAYS FROM GAMMA-RAY BURSTS  

SciTech Connect (OSTI)

Based on the experience gained during the four and a half years of the mission, the Fermi-LAT Collaboration has undertaken a comprehensive revision of the event-level analysis going under the name of Pass 8. Although it is not yet finalized, we can test the improvements in the new event reconstruction with the special case of the prompt phase of bright gamma-ray bursts (GRBs), where the signal-to-noise ratio is large enough that loose selection cuts are sufficient to identify gamma rays associated with the source. Using the new event reconstruction, we have re-analyzed 10 GRBs previously detected by the Large Area Telescope (LAT) for which an X-ray/optical follow-up was possible and found four new gamma rays with energies greater than 10 GeV in addition to the seven previously known. Among these four is a 27.4 GeV gamma ray from GRB 080916C, which has a redshift of 4.35, thus making it the gamma ray with the highest intrinsic energy ({approx}147 GeV) detected from a GRB. We present here the salient aspects of the new event reconstruction and discuss the scientific implications of these new high-energy gamma rays, such as constraining extragalactic background light models, Lorentz invariance violation tests, the prompt emission mechanism, and the bulk Lorentz factor of the emitting region.

Atwood, W. B. [Santa Cruz Institute for Particle Physics, Department of Physics and Department of Astronomy and Astrophysics, University of California at Santa Cruz, Santa Cruz, CA 95064 (United States); Baldini, L. [Universita di Pisa and Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, I-56127 Pisa (Italy); Bregeon, J.; Pesce-Rollins, M.; Sgro, C.; Tinivella, M. [Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, I-56127 Pisa (Italy); Bruel, P. [Laboratoire Leprince-Ringuet, Ecole polytechnique, CNRS/IN2P3, Palaiseau (France); Chekhtman, A. [Center for Earth Observing and Space Research, College of Science, George Mason University, Fairfax, VA 22030 (United States); Cohen-Tanugi, J. [Laboratoire Univers et Particules de Montpellier, Universite Montpellier 2, CNRS/IN2P3, F-34095 Montpellier (France); Drlica-Wagner, A.; Omodei, N.; Rochester, L. S.; Usher, T. L. [W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States); Granot, J. [Department of Natural Sciences, The Open University of Israel, 1 University Road, P.O. Box 808, Ra'anana 43537 (Israel); Longo, F. [Istituto Nazionale di Fisica Nucleare, Sezione di Trieste, I-34127 Trieste (Italy); Razzaque, S. [Department of Physics, University of Johannesburg, Auckland Park 2006 (South Africa); Zimmer, S., E-mail: melissa.pesce.rollins@pi.infn.it, E-mail: nicola.omodei@stanford.edu, E-mail: granot@openu.ac.il [Department of Physics, Stockholm University, AlbaNova, SE-106 91 Stockholm (Sweden)

2013-09-01T23:59:59.000Z

7

Building Address Locations -Assumes entire  

E-Print Network [OSTI]

Housman Building 80 E. Concord St R BU School of Medicine, Instructional Building 80 E. Concord St L BU JBuilding Address Locations - Assumes entire building unless noted Designation Submit through* 560, 4 BU Crosstown Center 801 Massachusetts Ave Floor 1, 2 BMC BCD Building 800 Harrison Avenue BCD BMC

Guenther, Frank

8

Fermi Gamma-Ray “Bubbles” from Stochastic Acceleration of Electrons  

Science Journals Connector (OSTI)

Gamma-ray data from Fermi Large Area Telescope reveal a bilobular structure extending up to ?50° above and below the Galactic Center. It has been argued that the gamma rays arise from hadronic interactions of high-energy cosmic rays which are advected out by a strong wind, or from inverse-Compton scattering of relativistic electrons accelerated at plasma shocks present in the bubbles. We explore the alternative possibility that the relativistic electrons are undergoing stochastic 2nd-order Fermi acceleration by plasma wave turbulence through the entire volume of the bubbles. The observed gamma-ray spectral shape is then explained naturally by the resulting hard electron spectrum modulated by inverse-Compton energy losses. Rather than a constant volume emissivity as in other models, we predict a nearly constant surface brightness, and reproduce the observed sharp edges of the bubbles.

Philipp Mertsch and Subir Sarkar

2011-08-23T23:59:59.000Z

9

Fermi Observations of Gamma-ray Bursts  

SciTech Connect (OSTI)

The gamma-ray emission mechanism of Gamma-ray bursts (GRBs) are still unknown. Fermi Gamma-ray Space Telescope successfully detected high-energy (> 100 MeV) emission from 17 GRBs since its launch. Fermi revealed the distinct temporal behaviors and extra spectral component from high-energy emission. These new observational results are driving many theoretical implications, such as leptonic, hadronic and afterglow origin. The highest energy photon detected by Fermi gives a constraint on the bulk Lorentz factor of the ultra-relativistic jets of GRBs. The impact of the Fermi GRB observations extends not only to the GRB-related issues but also to the outside GRB physics, such as quantum gravity and model of the extra galactic background light.

Ohno, Masanori [Institute of Space and Astronautical Science, JAXA, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210 (Japan)

2010-10-15T23:59:59.000Z

10

Radiographic apparatus for photographing entire jaws  

SciTech Connect (OSTI)

This disclosure relates to a dental radiographic apparatus for photographing the entire jaw designed to control the rotation of a rotary arm such that the film surface of a film holder mounted at one end of the rotary arm may rotate and move substantially at equal speed substantially equidistantly along the dental arch and that the X-ray beams irradiated upon the film surface from an X-ray generator mounted at the other end of the arm may fall on the dental arch at any point thereof at right angles with the arch. The apparatus makes it possible to obtain a very clear tomographic picture of a curved plane of the entire jaws, the picture being free of a double image of the teeth, partial change in enlargement ratio of the image obtained, and partial difference in the shade of the image obtained.

Nakano, K.

1985-01-22T23:59:59.000Z

11

FermiNews  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Jump to FermiNews back issues from 2003, 2002, 2001, 2000, 1999, 1998, 1997 or 1996. Jump to FermiNews back issues from 2003, 2002, 2001, 2000, 1999, 1998, 1997 or 1996. Adobe Acrobat readers are available free from Adobe at http://www.adobe.com/Acrobat/readstep.html . Readers are now available for Macintosh, Windows, SunOS, Solaris, HP-UX, Silicon Graphics IRIX, IBM AIX, and DOS. FermiNews Back Issues from 2004 June 1, 2004 Adobe Acrobat format HTML format No End In Sight Fermilab's Greatest Hits 26 Years of Quirks and Quarks The View From a Lens: Photographers Pick Their Favorites Hand-Crafting the News and Launching New Careers May 1, 2004 Adobe Acrobat format HTML format FermiNews Ends its Run Fermilab Prepares for its Future DASTOW '04: Wings and Wonders Time Exposure CDMS: New Dark Matter Result April 1, 2004 Adobe Acrobat format

12

Enrico Fermi Patents  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Patents Patents Fermi Home · Resources with Additional Information · Fermi Honored · Atoms for Peace · Centennial of Birth Marburger Speech · Stamp · Audio/Video Clips US PATENT 2,206,634 (Process for the Production of Radioactive Substances); E. Fermi, E. Amaldi, F. Rasetti, E. Segre, B. Pontecorvo; July 2, 1940. The process, for production of isotopes including transuranic elements by reaction of neutrons, employs means for generating neutrons having a high average energy, slowing down and scattering the neutrons by projecting them through a medium of an element of a class including H, He, Be, C, Si, and Pb, and then passing the neutrons into a mass of material containing an element capable of forming a radioactive isotope by neutron capture, including radioactive isotopes capable of emitting beta rays.

13

FermiNews  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Dialogue: Communicating Particle Physics in the 21st Century Dialogue: Communicating Particle Physics in the 21st Century The un-common language of science - Does particle physics need to find new ways of describing itself? Related FermiNews story Dialogue - FermiNews readers express their views: On May 14, Charles Abney from Grand Prairie, Texas, writes: Ms,Sirs: I have just received and read the lattest fermi news publication that you sent by mail (05/10/2002). The gentlemen in the article proposes that particle physics be grouped with astronomy,cosmology, string physics, and gravitational waves be grouped under one Science. From my own prespective from what I have learned from this site, other related sites and what books that I have read through our library and or purchased, is that on the very core level the diffrent sciences are all

14

Fermilab | About FermiLINK  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

About FermiLINK About FermiLINK Fermilab Today September 28, 2009 Mentors wanted for Diversity Office's FermiLINK program Fermilab Today October 5, 2009 Mentors wanted for Diversity Office's FermiLINK program Fermilab Today October 13, 2009 FermiLINK Q&A session Fermilab Today November 9, 2009 FermiLINK calls for mentees FermiLINK is FermilabÂ’s mentorship system designed to create an organizational network of leaders by providing opportunities for professional development and career management. This support structure creates access to the counsel and institutional knowledge of successful Fermilab professionals independent of the immediate supervisory hierarchy. FermiLINK provides web-based access to a host of mentors for issue-specific work-related challenges and opportunities. The network supports email,

15

Analysing the Entire Wikipedia History with Database Supported Haskell  

E-Print Network [OSTI]

Analysing the Entire Wikipedia History with Database Supported Haskell George Giorgidze1 , Torsten the entire Wikipedia history. DSH is a novel high-level database query facility allowing for the for on our experience of using Database Supported Haskell (DSH) [4] for analysing the entire history

Grust, Torsten

16

A notable family of entire intrinsic minimal graph...  

E-Print Network [OSTI]

to C1(O). This notion of C2 surface obviously includes the entire intrinsic graphs ...... F. Serra Cassano, Surface measures in Carnot-Carathéodory spaces, Calc.

2006-09-09T23:59:59.000Z

17

FermiLab  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

a high-energy physics laboratory, a high-energy physics laboratory, named after particle physicist pioneer Enrico Fermi, is located 30 miles west of Chicago. It is the home of the world's most powerful particle accelerator, the Tevatron, which was used to discover the top quark. For more information: Booster: There is a short linear accelerator and a 95 meter booster accelerator. Hydrogen is ionized (stripped of its electrons), leaving protons, which are accelerated to 8 GeV before injection into the main accelerator. Antiproton Production Protons are crashed into a target. Antiprotons found among the resulting particles are collected in the antiproton accumulator, and then sent in the opposite direction as the protons in the ring. Tevatron The main accelerator, the Tevatron is a synchrotron about 6.4

18

Thermodynamics of Ultracold Fermi Gases  

Science Journals Connector (OSTI)

We measure the equation of state of a low-temperature two-component ultracold Fermi gas for a wide range of interaction strengths. A detailed comparison with theories including...

Nascimbène, Sylvain; Navon, Nir; Chevy, Frédéric; Salomon, Christophe

19

11FermiNews  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

E E y e w i t n e s s t o H i s t o r y 6 D i a l o g u e B o x 8 B l a c k b o a r d A r t 13 T h e Ta l k o f t h e L a b US/CMS Project 10 F E R M I L A B A U. S. D E P A R T M E N T O F E N E R G Y L A B O R A T O R Y F N E E R W M S I Volume 22 Friday, April 2, 1999 Number 7 f Photo by Reidar Hahn Ned Goldwasser was present at the beginnings of a great adventure in high-energy physics, but on a day dedicated to him, he couldnÕt forget that the cities were burning in that formative time for Fermi National Accelerator Laboratory. Not a building had yet been raised on the 6,800-acre site in March 1967, when the newly named director, Robert R. Wilson, telephoned Goldwasser, then at the University of Illinois, asking him to come on board with the project. Goldwasser, who had served on the committee recommending potential laboratory sites to the Atomic Energy Commission, took the job and agreed to

20

FermiNews  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Particle Physics for Regular People-Recommended Readings Particle Physics for Regular People-Recommended Readings A High-Energy Bookshelf to Brush Up Your Bosons Written By Mike Perricone, Office of Public Affairs for February 6, 1998 Issue of FermiNews. Psychologist Oliver Sacks has Robin Williams portraying him on screen. Cosmologist Carl Sagan's fictional heroine explores the universe in the glamorous guise of Jodie Foster. Biologist Stephen Jay Gould muses about the Red Sox in the PBS megadocumentary "Baseball." Where are all the particle physicists? They're on a high-energy bookshelf near you. The authors of the best plain-language literature in particle physics might not yet have reached stardom, but their books offer a literate, accessible and engaging introduction to a field of science that has been known to intimidate the uninitiated. The stories of the discoveries of the particles at the heart of matter offer all the thrills of a good chase-one of the biggest chases of 20th-century science. From the wide field available, readers can start with a half dozen of the "best of the best" books for gaining an understanding of the reason for all the excitement.

Note: This page contains sample records for the topic "fermi reveals entire" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

Extremely Correlated Fermi Liquids B. Sriram Shastry  

E-Print Network [OSTI]

Extremely Correlated Fermi Liquids B. Sriram Shastry Physics Department, University of California the theory of an extremely correlated Fermi liquid with U ! 1. This liquid has an underlying auxiliary Fermi liquid Green's function that is further caparisoned by extreme correlations. The theory leads to two

California at Santa Cruz, University of

22

FermiCulture Subscription Form  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

The FermiCulture email list is used to send email announcements and reminders about upcoming cultural events at Fermilab (e.g., the Fermilab Arts, Film, and Lecture series). This is a private, announcement-only mail list and will never be used for spamming or discussions. Subscribers receive approximately five emails per month. Use the form below to subscribe to (or unsubscribe from) the FermiCulture list. The FermiCulture email list is used to send email announcements and reminders about upcoming cultural events at Fermilab (e.g., the Fermilab Arts, Film, and Lecture series). This is a private, announcement-only mail list and will never be used for spamming or discussions. Subscribers receive approximately five emails per month. Use the form below to subscribe to (or unsubscribe from) the FermiCulture list. Email address: Name (First Last): Subscribe to email list Unsubscribe from email list Send Reset The Regular Mailing List If you would like to receive mailings through the regular mail of upcoming cultural events at Fermilab and are not on our mailing list, then please fill out the information below. Name: Address: City: State: Zip: Country: E-mail:

23

The equivariant index theorem in entire cyclic cohomology.  

E-Print Network [OSTI]

Let G be a locally compact group acting smoothly and properly by isometries on a complete Riemannian manifold M, with compact quotient. There is an assembly map which associates to any G-equivariant K-homology class on M, an element of the topological K-theory of a suitable Banach completion B of the convolution algebra of continuous compactly supported functions on G. The aim of this paper is to calculate the composition of the assembly map with the Chern character in the entire cyclic homology of B. We prove an index theorem reducing this computation to a cup-product in bivariant entire cyclic cohomology. As a consequence we obtain an explicit localization formula which includes, as particular cases, the equivariant Atiyah-Segal-Singer index theorem when G is compact, and the Connes-Moscovici index theorem for G-coverings when G is discrete. The proof is based on the bivariant Chern character introduced in previous papers.

Denis Perrot.; 3 (2009) 261-307

24

Fermi Award Winners Saluted | Department of Energy  

Broader source: Energy.gov (indexed) [DOE]

Fermi Award Winners Saluted Fermi Award Winners Saluted Fermi Award Winners Saluted May 9, 2012 - 3:18pm Addthis President Barack Obama greets 2010 Fermi Award recipients Dr. Burton Richter, right, and his wife Laurose, and Dr. Mildred S. Dresselhaus, third from right, and her husband Gene, in the Oval Office, May 7, 2012. (Official White House Photo by Pete Souza) President Barack Obama greets 2010 Fermi Award recipients Dr. Burton Richter, right, and his wife Laurose, and Dr. Mildred S. Dresselhaus, third from right, and her husband Gene, in the Oval Office, May 7, 2012. (Official White House Photo by Pete Souza) Nafeesa Hunt Owens What is the Enrico Fermi Award? A Presidential award, the Fermi Award is one of the oldest and most prestigious science and technology honors bestowed by the U.S. Government.

25

High-Tc superconductivity in entirely end-bonded multi-walled carbon nanotubes  

E-Print Network [OSTI]

We report that entirely end-bonded multi-walled carbon nanotubes (MWNTs) can show superconductivity with the transition temperature Tc as high as 12K that is approximately 40-times larger than those reported in ropes of single-walled nanotubes. We find that emergence of this superconductivity is very sensitive to junction structures of Au electrode/MWNTs. This reveals that only MWNTs with optimal numbers of electrically activated shells, which are realized by the end-bonding, can allow the superconductivity due to inter shell effects.

I. Takesue; J. Haruyama; N. Kobayashi; S. Chiashi; S. Maruyama; T. Sugai; H. Shinohara

2005-12-16T23:59:59.000Z

26

Fermi liquid theory for high temperature superconductors  

SciTech Connect (OSTI)

In this article the Fermi liquid theory of metals is discussed starting from Luttinger's theorem. The content of Luttinger's Theorem and its implications for microscopic theories of high temperature superconductors are discussed. A simple quasi-2d Fermi liquid theory is introduced and some of its properties are calculated. It is argued that a number of experiments on YBa/sub 2/Cu/sub 3/O/sub 6+x/, x > 0.5, strongly suggest the existence of a Fermi surface and thereby a Fermi liquid normal state. 25 refs., 1 fig.

Bedell, K.S.

1988-01-01T23:59:59.000Z

27

Self-Organized Networks and Lattice Effects in High Temperature Superconductors II: Fermi Arc Anomalies  

E-Print Network [OSTI]

The self-organized dopant percolative filamentary model, entirely orbital in character (no fictive spins), explains the evolution with doping of Fermi arcs observed by ARPES, including the previously unexplained abrupt transitions in quasiparticle strength observed near optimal doping in cuprate high temperature superconductors. Similarly abrupt transitions are also observed in time-resolved picosecond relaxation spectroscopy at 1.5 eV, and these are explained as well, using no new assumptions and no adjustable parameters.

J. C. Phillips

2006-11-07T23:59:59.000Z

28

Video: Honoring Science that Matters with the Enrico Fermi Award...  

Energy Savers [EERE]

Honoring Science that Matters with the Enrico Fermi Award Video: Honoring Science that Matters with the Enrico Fermi Award February 11, 2014 - 9:50am Addthis The Fermi Award is a...

29

MagLab - Pioneers in Electricity and Magnetism: Enrico Fermi  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Enrico Fermi (1901-1954) Enrico Fermi Enrico Fermi was a titan of twentieth-century physics. Adept in both theory and experiment, the Italian-born American outlined the statistical...

30

Phonon exchange in dilute Fermi-Bose mixtures: Tailoring the Fermi-Fermi interaction  

Science Journals Connector (OSTI)

We consider a mixture of a single-component Bose gas and a two-component Fermi gas at temperatures where the Bose gas is almost fully condensed. In such a mixture, two fermionic atoms can interact with each other by exchanging a phonon that propagates through the Bose condensate. We calculate the interaction potential due to this mechanism, and determine the effective s-wave scattering length for two fermions that interact, both directly by the interatomic potentials as well as by the above-mentioned exchange mechanism. We find that the effective scattering length is quite sensitive to changes in the condensate density, and becomes strongly energy dependent. In addition, we consider the mechanical stability of these mixtures, and also calculate the dispersion and the damping of the various collisionless collective modes of the gas.

M. J. Bijlsma; B. A. Heringa; H. T. C. Stoof

2000-04-05T23:59:59.000Z

31

Enrico Fermi Award Ceremony | Department of Energy  

Broader source: Energy.gov (indexed) [DOE]

Enrico Fermi Award Ceremony Enrico Fermi Award Ceremony Enrico Fermi Award Ceremony June 22, 2006 - 2:31pm Addthis Remarks Prepared for Energy Secretary Samuel Bodman The Department of Energy has a very rich scientific tradition and one of the best things about being Energy Secretary is from time to time I have an opportunity to acknowledge that tradition and the very real impact it continues to have on the lives of all Americans.Today is one of those days. We are here to honor Art Rosenfeld with our nation's highest scientific honor: the Enrico Fermi award recognizing a lifetime of highly relevant and public-spirited work in the cause of energy efficiency as well as pioneering discoveries in experimental and particle physics and the generosity of spirit and intellectual rigor with which he has carried it

32

Enrico Fermi: Audio/Video Clips  

Office of Scientific and Technical Information (OSTI)

Audio/Video Clips Audio/Video Clips Fermi Home · Resources with Additional Information · Fermi Honored · Atoms for Peace · Centennial of Birth Marburger Speech · Stamp · Patents Video Clip Fermi's account of the first nuclear chain reaction on December 2,1942 (from the colloquium of the 10th Anniversary of the event), with artwork of the reactor by Argonne National Laboratory (ANL). Due to the secrecy of the event, no photographs were taken of the reactor. Introduction by Crawford Greenwalt. Courtesy of ANL (5749K; 3 minutes, 50 seconds) Download Flash for video. Horizontal Divider Audio Clips Download QuickTime for audio files. From "Century of the Atom," produced by the U.S. Atomic Energy Commission Alternative cannot be provided. Download QuickTime Ten years after the experiment, Fermi recalls his confidence in the success of the first self-sustaining chain reaction. (197K; 23 seconds)

33

Enrico Fermi Award Ceremony | Department of Energy  

Broader source: Energy.gov (indexed) [DOE]

Enrico Fermi Award Ceremony Enrico Fermi Award Ceremony Enrico Fermi Award Ceremony June 22, 2006 - 2:31pm Addthis Remarks Prepared for Energy Secretary Samuel Bodman The Department of Energy has a very rich scientific tradition and one of the best things about being Energy Secretary is from time to time I have an opportunity to acknowledge that tradition and the very real impact it continues to have on the lives of all Americans.Today is one of those days. We are here to honor Art Rosenfeld with our nation's highest scientific honor: the Enrico Fermi award recognizing a lifetime of highly relevant and public-spirited work in the cause of energy efficiency as well as pioneering discoveries in experimental and particle physics and the generosity of spirit and intellectual rigor with which he has carried it

34

Fermi National Accelerator Laboratory November 2013  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

g-2 Experiment A national laboratory funded by the Office of Science of the Department of Energy. www.fnal.gov Fermi National Accelerator Laboratory November 2013 By studying the...

35

Graphic Standards Fermi National Accelerator Laboratory 2014  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

out to white. The logo must always have a crisp contrast with the background color or image. the height of the logomark of an inch wide " Graphic Standards Fermi...

36

Generalized charge-screening in relativistic Thomas–Fermi model  

SciTech Connect (OSTI)

In this paper, we study the charge shielding within the relativistic Thomas-Fermi model for a wide range of electron number-densities and the atomic-number of screened ions. A generalized energy-density relation is obtained using the force-balance equation and taking into account the Chandrasekhar's relativistic electron degeneracy pressure. By numerically solving a second-order nonlinear differential equation, the Thomas-Fermi screening length is investigated, and the results are compared for three distinct regimes of the solid-density, warm-dense-matter, and white-dwarfs (WDs). It is revealed that our nonlinear screening theory is compatible with the exponentially decaying Thomas-Fermi-type shielding predicted by the linear response theory. Moreover, the variation of relative Thomas-Fermi screening length shows that extremely dense quantum electron fluids are relatively poor charge shielders. Calculation of the total number of screening electrons around a nucleus shows that there is a position of maximum number of screening localized electrons around the screened nucleus, which moves closer to the point-like nucleus by increase in the plasma number density but is unaffected due to increase in the atomic-number value. It is discovered that the total number of screening electrons, (N{sub s}?r{sub TF}{sup 3}/r{sub d}{sup 3} where r{sub TF} and r{sub d} are the Thomas-Fermi and interparticle distance, respectively) has a distinct limit for extremely dense plasmas such as WD-cores and neutron star crusts, which is unique for all given values of the atomic-number. This is equal to saying that in an ultrarelativistic degeneracy limit of electron-ion plasma, the screening length couples with the system dimensionality and the plasma becomes spherically self-similar. Current analysis can provide useful information on the effects of relativistic correction to the charge screening for a wide range of plasma density, such as the inertial-confined plasmas and compact stellar objects.

Akbari-Moghanjoughi, M. [Department of Physics, Faculty of Sciences, Azarbaijan Shahid Madani University, 51745-406 Tabriz, Iran and International Centre for Advanced Studies in Physical Sciences and Institute for Theoretical Physics, Ruhr University Bochum, D-44780 Bochum (Germany)

2014-10-15T23:59:59.000Z

37

Fermi 3/29/02  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

September 20, 2002 September 20, 2002 Number 15 f I N S I D E : 6 L a s t R i t e s 8 F Y I 1 2 C o m p u t i n g b y t h e Tr u c k l o a d Jeff Kallenbach, Fermilab and Jon Link, BooNE collaboration New Neutrino Experiment at Fermilab Goes Live 2 2 FERMINEWS Friday, September 20, 2002 Scientists of the Booster Neutrino Experiment collaboration announced on September 9 that a new detector at the U.S. Department of Energy's Fermi National Accelerator Laboratory has observed its first neutrino events. The BooNE scientists identified neutrinos that created ring-shaped flashes of light inside a 250,000-gallon detector filled with mineral oil. The major goal of the MiniBooNE experiment, the first phase of the BooNE project, is either to confirm or refute startling experimental results reported by a group of scientists at the Los Alamos National Laboratory. In 1995, the

38

Continuous transitions between composite Fermi liquid and Landau Fermi liquid: A route to fractionalized Mott insulators  

E-Print Network [OSTI]

One of the most successful theories of a non-Fermi-liquid metallic state is the composite Fermi-liquid (CFL) theory of the half-filled Landau level. In this paper, we study continuous quantum phase transitions out of the ...

Barkeshli, Maissam

39

Study of microwave/gamma-ray properties for Fermi-LAT bright AGNs  

E-Print Network [OSTI]

Blazars are a small fraction of all extragalactic sources but, unlike other objects, they are strong emitters across the entire electromagnetic spectrum. Recent data in the microwave region of the electromagnetic spectrum have become available to allow for systematic studies of blazars over large cosmological volumes. This frequency band is indeed particularly suited for the selection of blazars since at these frequencies the contamination from radio extended components with steep spectra is no longer present and the emission from the accretion process is negligible. During the first 3 months of scientific operations Fermi-LAT detected 106 bright, high-galactic latitude (| b |> 10 deg) AGNs with high significance. In this study we investigate the possible relations between the microwave and the gamma-ray emissions for Fermi-LAT detected AGNs belonging to WMAP 5th year bright source catalog.

Gasparrini, D; Giommi, P; Pittori, C; Colafrancesco, S

2009-01-01T23:59:59.000Z

40

Soliton trains in Bose-Fermi mixtures  

E-Print Network [OSTI]

We theoretically consider the formation of bright solitons in a mixture of Bose and Fermi degenerate gases. While we assume the forces between atoms in a pure Bose component to be effectively repulsive, their character can be changed from repulsive to attractive in the presence of fermions provided the Bose and Fermi gases attract each other strongly enough. In such a regime the Bose component becomes a gas of effectively attractive atoms. Hence, generating bright solitons in the bosonic gas is possible. Indeed, after a sudden increase of the strength of attraction between bosons and fermions (realized by using a Feshbach resonance technique or by firm radial squeezing of both samples) soliton trains appear in the Bose-Fermi mixture.

T. Karpiuk; M. Brewczyk; S. Ospelkaus-Schwarzer; K. Bongs; M. Gajda; K. Rzazewski

2004-04-14T23:59:59.000Z

Note: This page contains sample records for the topic "fermi reveals entire" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

Fermi 3/29/02  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

February 14, 2003 February 14, 2003 Number 3 f Fermilab photo I N S I D E : 2 C r a c k i n g t h e N e u t r i n o C o d e 8 To u g h D a y s A h e a d w i t h F Y 0 4 S c i e n c e F u n d i n g 1 2 H i s t o r i c Tu r n s i n T h e W i n d m i l l C i t y First-Hand Account 6 2 FERMINEWS Friday, February 14, 2003 Neutrinos are everywhere. Capable of traversing the entire earth at close to the speed of light, these particles shine no light, and only very rarely does one of them interact with anything at all. Penetrating every corner of the universe, billions of neutrinos cross your body in a tiny fraction of a second. From its very beginning, Fermilab (originally called the National Accelerator Laboratory) has helped to unravel the secrets of these ghost-like particles. The first experiment at NAL, labeled E1A and proposed in June 1970, used neutrinos to search for a force-carrying particle called the W boson. Since

42

President Obama Welcomes 2013 Fermi Award Winners to the White...  

Broader source: Energy.gov (indexed) [DOE]

Welcomes 2013 Fermi Award Winners to the White House President Obama Welcomes 2013 Fermi Award Winners to the White House February 3, 2014 - 6:24pm Addthis Energy Secretary Ernest...

43

2012 Annual Planning Summary for Fermi Site Office  

Broader source: Energy.gov [DOE]

The ongoing and projected Environmental Assessments and Environmental Impact Statements for 2012 and 2013 within Fermi Site Office.

44

2013 Annual Planning Summary for the FERMI Site Office  

Broader source: Energy.gov [DOE]

The ongoing and projected Environmental Assessments and Environmental Impact Statements for 2013 and 2014 within the FERMI Site Office.

45

Fermi 3/29/02  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

October 2003 October 2003 Number 14 f Photo by Fred Ullrich I N S I D E : 2 P o i n t o f Vi e w : R u n I I I t 's Ti m e t o M o v e O n - To g e t h e r 5 F e r m i l a b To d a y L a u n c h e s R e s u l t o f t h e We e k 1 0 O n l y Y O U C a n A c h i e v e a S a f e S h u t d o w n 1 4 P r o f i l e i n P h y s i c s : D a n J o h n s o n M o v i n g U p - A n d A r o u n d Shutdown at Fermilab 6 TOGETHER Last month Fermilab Director Mike Witherell announced the cancellation of the CDF and DZero silicon detector upgrades for Run II. While not entirely unexpected, this announcement was a great disappointment to many of us. I have lost count of how many times I have been asked how I feel about this decision. This brief article is an attempt to answer that question. It's a very personal view, not an official statement of laboratory or experiment policy. I haven't made any attempt at spin control, and aspects of the drama are

46

Genuine tripartite entanglement in the non-interacting Fermi gas  

E-Print Network [OSTI]

We study genuine tripartite entanglement shared among the spins of three localized fermions in the non-interacting Fermi gas at zero temperature. Firstly, we prove analytically with the aid of entanglement witnesses that in a particular configuration the three fermions are genuinely tripartite entangled. Then various three-fermion configurations are investigated in order to quantify and calculate numerically the amount of genuine tripartite entanglement present in the system. Further we give a lower and an upper limit to the maximum diameter of the three-fermion configuration below which genuine tripartite entanglement exists and find that this distance is comparable with the maximum separation between two entangled fermions. The upper and lower limit turn to be very close to each other indicating that the applied witness operator is well suited to reveal genuine tripartite entanglement in the collection of non-interacting fermions.

T. Vértesi

2007-01-31T23:59:59.000Z

47

Investigation of the deformed fermi surfaces mechanism for pairing of two species of fermions with mismatched fermi surfaces  

E-Print Network [OSTI]

INVESTIGATION OF THE DEFORMED FERMI SURFACES MECHANISM FOR PAIRING OF TWO SPECIES OF FERMIONS WITH MISMATCHED FERMI SURFACES A Thesis by JIANXU LU Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment... of the requirements for the degree of MASTER OF SCIENCE December 2007 Major Subject: Physics INVESTIGATION OF THE DEFORMED FERMI SURFACES MECHANISM FOR PAIRING OF TWO SPECIES OF FERMIONS WITH MISMATCHED FERMI SURFACES A Thesis by JIANXU LU Submitted to the Office...

Lu, Jianxu

2008-10-10T23:59:59.000Z

48

FermiGrid - experience and future plans  

SciTech Connect (OSTI)

Fermilab supports a scientific program that includes experiments and scientists located across the globe. In order to better serve this community, Fermilab has placed its production computer resources in a Campus Grid infrastructure called 'FermiGrid'. The FermiGrid infrastructure allows the large experiments at Fermilab to have priority access to their own resources, enables sharing of these resources in an opportunistic fashion, and movement of work (jobs, data) between the Campus Grid and National Grids such as Open Science Grid and the WLCG. FermiGrid resources support multiple Virtual Organizations (VOs), including VOs from the Open Science Grid (OSG), EGEE and the Worldwide LHC Computing Grid Collaboration (WLCG). Fermilab also makes leading contributions to the Open Science Grid in the areas of accounting, batch computing, grid security, job management, resource selection, site infrastructure, storage management, and VO services. Through the FermiGrid interfaces, authenticated and authorized VOs and individuals may access our core grid services, the 10,000+ Fermilab resident CPUs, near-petabyte (including CMS) online disk pools and the multi-petabyte Fermilab Mass Storage System. These core grid services include a site wide Globus gatekeeper, VO management services for several VOs, Fermilab site authorization services, grid user mapping services, as well as job accounting and monitoring, resource selection and data movement services. Access to these services is via standard and well-supported grid interfaces. We will report on the user experience of using the FermiGrid campus infrastructure interfaced to a national cyberinfrastructure--the successes and the problems.

Chadwick, K.; Berman, E.; Canal, P.; Hesselroth, T.; Garzoglio, G.; Levshina, T.; Sergeev, V.; Sfiligoi, I.; Timm, S.; Yocum, D.; /Fermilab

2007-09-01T23:59:59.000Z

49

Fermi Site Office Post Office Box 2000  

Broader source: Energy.gov (indexed) [DOE]

Fermi Site Office Fermi Site Office Post Office Box 2000 Batavia, Illinois 60510 JAN 14 2011 Scott Blake Harris, General Counsel GC-1 FORS SUBJECT: FERMl SITE OFFICE (FSO) 201 1 ANNUAL NATIONAL ENVIRONMENTAL POLICY ACT (NEPA) PLANNING SUIMMARY The Department of Energy (DOE) Order 451 .I B, Change 2, requires Secretarial Officers and Heads of Field Organizations to submit a NEPA Annual Planning Summary to the Office of General Counsel. Per your December 8, 2010 memorandum and guidance provided by the Office of NEPA Policy and Compliance (GC-54), our Annual NEPA Planning Summary is enclosed. We have identified one on-going environmental assessment (EA). No environmental impact statements (EISs) are on-going and two new EAs and one EIS are expected to be prepared beginning in the next 12 to 24 months.

50

Nuclear response beyond the Fermi gas model  

E-Print Network [OSTI]

The Fermi gas model, while providing a reasonable qualitative description of the continuum nuclear response, does not include the effects of dynamical nucleon-nucleon correlations in the initial and final states, that have long been recognized to play a critical role in specific kinematical regions. We review a many-body approach in which these effects are consistently taken into account and discuss the results of a calculation of the quasielastic neutrino-oxygen cross section as an illustrative example.

Omar Benhar

2003-07-14T23:59:59.000Z

51

Thomas-Fermi model: The leading correction  

Science Journals Connector (OSTI)

The correct treatment of strongly bound electrons is grafted smoothly onto the Thomas-Fermi computation of the total binding energy of neutral atoms. This provides a clearcut demonstration of the leading correction of relative order Z-13 which, with effects of relative order Z-23, gives an accurate account of the binding energy over a wide range of Z values. There is a brief discussion of relativistic corrections, with results that are somewhat at variance with previous numerical estimates.

Julian Schwinger

1980-11-01T23:59:59.000Z

52

Thomas-Fermi model: The second correction  

Science Journals Connector (OSTI)

A simple derivation is given for the first quantum correction to the Thomas-Fermi kinetic energy. Its application to the total binding energy of neutral atoms exploits the technique for handling strongly bound electrons that was developed in a preceding paper, and justifies the numerical value of the second correction adopted there. A proposal is made for extrapolating this improved description to the outer regions of the atom.

Julian Schwinger

1981-11-01T23:59:59.000Z

53

Categorical Exclusion Determinations: Fermi Site Office | Department of  

Broader source: Energy.gov (indexed) [DOE]

Fermi Site Office Fermi Site Office Categorical Exclusion Determinations: Fermi Site Office Categorical Exclusion Determinations issued by Fermi Site Office. DOCUMENTS AVAILABLE FOR DOWNLOAD June 7, 2013 CX-010532: Categorical Exclusion Determination Various Demolition Jobs CX(s) Applied: B1.23 Date: 06/07/2013 Location(s): Illinois Offices(s): Fermi Site Office March 27, 2013 CX-010387: Categorical Exclusion Determination The Geotechnical Investigation of the Long Baseline Neutrino Experiment Detector Site in South Dakota CX(s) Applied: B3.1 Date: 03/27/2013 Location(s): South Dakota Offices(s): Fermi Site Office February 20, 2013 CX-010388: Categorical Exclusion Determination Northern Illinois Center for Accelerator and Detector Development Extrusion Line Facility CX(s) Applied: B1.15

54

Local Fermi gas in inclusive muon capture from nuclei  

E-Print Network [OSTI]

We compare local Fermi gas and shell model in muon capture in nuclei in order to estimate the effect of finite nuclear size in low energy weak reactions.

J. E. Amaro; J. Nieves; M. Valverde; C. Maieron

2006-05-20T23:59:59.000Z

55

Enrico Fermi Achieves First Self Sustain Nuclear Chain Reaction...  

National Nuclear Security Administration (NNSA)

Self Sustain Nuclear Chain Reaction Chicago, IL Metallurgical Laboratory scientists led by Enrico Fermi achieve the first self-sustained nuclear chain reaction in pile...

56

Surface localized states and the Fermi contour of Pd(001)  

Science Journals Connector (OSTI)

Angle-resolved photoemission measurements of the surface localized electronic states of the clean Pd(001) surface are presented. Several surface localized levels were observed, in qualitative agreement with an existing surface band-structure calculation. In particular, a state was observed which crosses the Fermi level (EF) near the X¯ point of the surface Brillouin zone. The segment of the Fermi contour derived from this crossing lies largely within a gap in the projected bulk Fermi surface and is parallel to the Brillouin-zone edge. The nesting properties of this segment of the Fermi contour suggest the possibility of a fairly strong electronic coupling to phonon excitations.

G. S. Elliott, K. E. Smith, and S. D. Kevan

1991-02-15T23:59:59.000Z

57

The free states-related Fermi pocket of cuprate superconductors  

E-Print Network [OSTI]

To stress the effect of the pairing position deviating from the Fermi level, we must investigate the pairs in the wave vector space, and then we use the dynamic equation to study some correlation functions. This article shows that the Fermi pocket is related to the effect of free electron states on the ARPES experiment. This also leads us to understand why the Fermi arc appears in Bi2212 while the Fermi pocket appears in Bi2201 with the valence bandwidth and the work function known for them.

Tian De Cao

2010-07-13T23:59:59.000Z

58

2011 Annual Planning Summary for Fermi Site Office (FSO)  

Broader source: Energy.gov [DOE]

The ongoing and projected Environmental Assessments and Environmental Impact Statements for 2011 and 2012 within the Fermi Site Office (See Science APS).

59

Probabilistic ideas in the theory of Fermi fields: Stochastic quantization of the Fermi oscillator  

Science Journals Connector (OSTI)

We give a complete description of the Fermi oscillator in terms of ordinary, numerical-valued, Markov processes. This description includes a path-integral formulation for the Hamiltonian semigroup and for the configurational Schwinger functions and the explicit formulation and solution of the stochastic differential equations describing the system in the sense of Nelson's stochastic mechanics.

Gian Fabrizio De Angelis; Diego de Falco; Francesco Guerra

1981-04-15T23:59:59.000Z

60

Investigation of the deformed fermi surfaces  

E-Print Network [OSTI]

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110 viii LIST OF FIGURES FIGURE Page 1 Gap of Sarma?s solution III with N(0)V=0.3, ?T = 1k BT = 1000/?BCS 6 2 Energy ofSarma?s solution III with N(0)V=0.3, ?T = 1k BT = 1000/?BCS 6 3 A rough picture of fermi surfaces of FF states... relative to the chemical potential ??. This Hamiltonian reduces to the corresponding one in 4 the BCS theory if h ? ?BH is set to zero. As in the BCS theory, which is for an s-wave superconductor, Sarma assumed: Vkk? = ? ?? ?? V if |?k| < planckover2pi1?D...

Lu, Jianxu

2009-05-15T23:59:59.000Z

Note: This page contains sample records for the topic "fermi reveals entire" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Shear Viscosity of a Unitary Fermi Gas  

E-Print Network [OSTI]

We present the first ab initio determination of the shear viscosity eta of the Unitary Fermi Gas, based on finite temperature quantum Monte Carlo calculations and the Kubo linear-response formalism. We determine the temperature dependence of the shear viscosity to entropy density ratio eta/s. The minimum of eta/s appears to be located above the critical temperature for the superfluid-to-normal phase transition with the most probable value being eta/s approx 0.2 hbar/kB, which almost saturates the Kovtun-Son-Starinets universal value hbar/(4 pi kB).

Gabriel Wlaz?owski; Piotr Magierski; Joaquín E. Drut

2012-04-01T23:59:59.000Z

62

Particle correlations in a Fermi superfluid  

Science Journals Connector (OSTI)

We discuss the correlations between particles of different momentum in a superfluid Fermi gas, accessible through noise measurements of the absorption images of the expanded gas. We include two elements missing from the simplest treatment, based on the BCS wavefunction: the explicit use of a conserving approximation satisfying particle number conservation and the inclusion of the contribution from Cooper pairs at finite momentum. We expect the latter to be a significant issue in the strongly correlated state emerging in the BCS-Bose-Einstein condensate (BEC) crossover.

A. Lamacraft

2006-01-20T23:59:59.000Z

63

Fermi surfaces and anomalous transport in quasicrystals  

Science Journals Connector (OSTI)

Electronic transport properties of quasicrystals are discussed theoretically. By means of ab initio linear muffin tin orbitals calculations, electronic band structure and corresponding Fermi surfaces of several quasicrystalline approximants are obtained. A criterion for distinguishing between metallic and anomalous transport properties in intermetallics is proposed. Unconventional temperature dependence of conductivity of quasicrystals and approximants is addressed in a second part. It is shown that power law exponents can be directly deduced from scaling analysis of the Kubo formula. Finally in relation to our results, we briefly summarize actual knowledge on low temperature transport regimes.

S. Roche and T. Fujiwara

1998-11-01T23:59:59.000Z

64

DataTrends: Entire series of reports | ENERGY STAR Buildings & Plants  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Entire series of reports Entire series of reports Secondary menu About us Press room Contact Us Portfolio Manager Login Facility owners and managers Existing buildings Commercial new construction Industrial energy management Small business Service providers Service and product providers Verify applications for ENERGY STAR certification Design commercial buildings Energy efficiency program administrators Commercial and industrial program sponsors Associations State and local governments Federal agencies Tools and resources Training In This Section Campaigns Commercial building design Communications resources Energy management guidance Financial resources Portfolio Manager Products and purchasing Recognition Research and reports Service and product provider (SPP) resources Success stories Target Finder

65

FermiNews - December 11, 1998  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

December 11, 1998 | Number 23 December 11, 1998 | Number 23 FermiNews Main Page Response in FermiNews, 05/12/2000 Santa and sleigh Santa at Nearly the Speed of Light by Arnold Pompos, Purdue University, and Sharon Butler, Office of Public Affairs About this time of year, inquisitive children of a certain age begin to question whether Santa is real. After all, Santa has a major delivery problem. There are some 2 billion children in the world expecting Christmas presents. Assuming an average of 2.5 children per household, then, Santa has to visit about 800 million homes scattered about the globe. The distance Santa has to travel can be estimated from the following. First, while the surface area of Earth is about 1014 square meters, only about 30 percent of that is land mass, or about 0.3 x 1014 square meters. Second, weÂ’ll assume, for simplicityÂ’s sake, that the 800 million homes are equally distributed on this land mass. Dividing 0.3 x 1014 by 800 million gives 4 x 104 square meters occupied by every household (about six football fields); the square root of that is the distance between households, about 200 meters. Multiply this by the 800 million households to get the distance Santa must travel on Christmas Eve to deliver all the childrenÂ’s gifts: 160 million kilometers, farther than the distance from here to the sun.

66

ABJM theory as a Fermi gas  

E-Print Network [OSTI]

The partition function on the three-sphere of many supersymmetric Chern-Simons-matter theories reduces, by localization, to a matrix model. We develop a new method to study these models in the M-theory limit, but at all orders in the 1/N expansion. The method is based on reformulating the matrix model as the partition function of an ideal Fermi gas with a non-trivial, one-particle quantum Hamiltonian. This new approach leads to a completely elementary derivation of the N^{3/2} behavior for ABJM theory and N=3 quiver Chern-Simons-matter theories. In addition, the full series of 1/N corrections to the original matrix integral can be simply determined by a next-to-leading calculation in the WKB or semiclassical expansion of the quantum gas, and we show that, for several quiver Chern-Simons-matter theories, it is given by an Airy function. This generalizes a recent result of Fuji, Hirano and Moriyama for ABJM theory. It turns out that the semiclassical expansion of the Fermi gas corresponds to a strong coupling expansion in type IIA theory, and it is dual to the genus expansion. This allows us to calculate explicitly non-perturbative effects due to D2-brane instantons in the AdS background.

Marcos Marino; Pavel Putrov

2012-03-14T23:59:59.000Z

67

Fermi Large Area Telescope Third Source Catalog  

E-Print Network [OSTI]

We present the third Fermi Large Area Telescope source catalog (3FGL) of sources in the 100~MeV--300~GeV range. Based on the first four years of science data from the Fermi Gamma-ray Space Telescope mission, it is the deepest yet in this energy range. Relative to the 2FGL catalog, the 3FGL catalog incorporates twice as much data as well as a number of analysis improvements, including improved calibrations at the event reconstruction level, an updated model for Galactic diffuse gamma-ray emission, a refined procedure for source detection, and improved methods for associating LAT sources with potential counterparts at other wavelengths. The 3FGL catalog includes 3033 sources above 4 sigma significance, with source location regions, spectral properties, and monthly light curves for each. Of these, 78 are flagged as potentially being due to imperfections in the model for Galactic diffuse emission. Twenty-five sources are modeled explicitly as spatially extended, and overall 232 sources are considered as identifie...

,

2015-01-01T23:59:59.000Z

68

Fermi Liquid Instabilities in the Spin Channel  

SciTech Connect (OSTI)

We study the Fermi surface instabilities of the Pomeranchuk type in the spin triplet channel with high orbital partial waves (F{sub l}{sup a} (l > 0)). The ordered phases are classified into two classes, dubbed the {alpha} and {beta}-phases by analogy to the superfluid {sup 3}He-A and B-phases. The Fermi surfaces in the {alpha}-phases exhibit spontaneous anisotropic distortions, while those in the {beta}-phases remain circular or spherical with topologically non-trivial spin configurations in momentum space. In the {alpha}-phase, the Goldstone modes in the density channel exhibit anisotropic overdamping. The Goldstone modes in the spin channel have nearly isotropic underdamped dispersion relation at small propagating wavevectors. Due to the coupling to the Goldstone modes, the spin wave spectrum develops resonance peaks in both the {alpha} and {beta}-phases, which can be detected in inelastic neutron scattering experiments. In the p-wave channel {beta}-phase, a chiral ground state inhomogeneity is spontaneously generated due to a Lifshitz-like instability in the originally nonchiral systems. Possible experiments to detect these phases are discussed.

Wu, Congjun; /Santa Barbara, KITP; Sun, Kai; Fradkin, Eduardo; /Illinois U., Urbana; Zhang, Shou-Cheng; /Stanford U., Phys. Dept.

2010-03-16T23:59:59.000Z

69

9 Fermi 10/20/00  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

20, 2000 20, 2000 Number 18 f Photo by Reidar Hahn I N S I D E : 4 S a v i n g t h e D a y 6 K e e p i n g i t C o o l 1 0 C o n t i n u i n g E d u c a t i o n i n t h e M a i n C o n t r o l R o o m 1 2 F a m o u s i n S i c i l y 1 4 F e r m i l a b Aw a r d W i n n e r s Millie Comes to Fermilab 2 Millie f Comes to Fermilab 2 FERMINEWS October 20, 2000 by Judy Jackson It was a special pleasure, Millie Dresselhaus said, to visit the physics laboratory named in honor of her former teacher at the University of Chicago, Enrico Fermi. During her September 27-28 visit to Fermilab for an onsite DOE review of the laboratory, Dresselhaus, director of the Department of EnergyÕs Office of Science, spoke with respect and affection of the professor she knew during her years as a University of Chicago graduate student, She referred often to FermiÕs legendary concern for graduate students and young physicists.

70

Enrico Fermi's Impact on Science - John Marburger Speech  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Fermi Home · Resources with Additional Information · Fermi Honored · Atoms for Peace · Centennial of Birth Fermi Home · Resources with Additional Information · Fermi Honored · Atoms for Peace · Centennial of Birth Stamp · Patents · Audio/Video Clips Enrico Fermi's Impact on Science Address given at the Italian Embassy Washington, D.C. Centennial Celebration of the Birth of Enrico Fermi November 27, 2001 Dr. John H. Marburger III President's Science Adviser and Director, Office of Science and Technology Policy It is a great honor to be invited to speak of Enrico Fermi on the occasion of his centennial birthday. Fermi was a physicist's physicist whose legacy was one of style as well of substance - a style so attractive and so productive for science that it became substantive in itself. I thank Secretary Abraham, Deputy Secretary Blake and Ambassador Salleo for this unique opportunity to pay tribute to one of the giants of twentieth century intellectual life. It is also an honor to share the program with three other eminent scientists and administrators, Daniele Amati, Luciano Maiani and Harold Agnew.

71

"Where is Everybody?" An Account of Fermi's Question  

DOE R&D Accomplishments [OSTI]

Enrico Fermi's famous question, now central to debates about the prevalence of extraterrestrial civilizations, arose during a luncheon conversation with Emil Konopinski, Edward Teller, and Herbert York in the summer of 1950. Fermi's companions on that day have provided accounts of the incident.

Jones, E. M.

1985-03-01T23:59:59.000Z

72

Symmetric invariant manifolds in the Fermi-Pasta-Ulam lattice  

E-Print Network [OSTI]

which represent the material elements of the string. Each of the point masses is an oscillator Introduction The Fermi-Pasta-Ulam (FPU) lattice is a discrete model for a continuous nonlinear string, introduced by E. Fermi, J. Pasta and S. Ulam [7]. This string is modeled by a finite number of point masses

Rink, Bob

73

Angle-Based Methods for Mobile Robot Navigation: Reaching the Entire Plane  

E-Print Network [OSTI]

pixel could be the robot's goal, and is painted gray if it is reachable by (left) the basic control lawAngle-Based Methods for Mobile Robot Navigation: Reaching the Entire Plane Rice University.rice.edu argyros@ics.forth.gr Abstract-- Popular approaches for mobile robot navigation involve range information

Trahanias, Panos

74

Angle-Based Methods for Mobile Robot Navigation: Reaching the Entire Plane  

E-Print Network [OSTI]

could be the robot's goal, and is painted gray if it is reachable by (left) the basic control lawAngle-Based Methods for Mobile Robot Navigation: Reaching the Entire Plane Kostas E. Bekris1 for mobile robot navigation involve range information and metric maps of the workspace. For many sensors

Trahanias, Panos

75

Entirely passive heat-pipe apparatus capable of operating against gravity  

DOE Patents [OSTI]

The disclosure is directed to an entirely passive heat pipe apparatus capable of operating against gravity for vertical distances in the order of 3 to 7 and more. A return conduit into which an inert gas is introduced is used to lower the specific density of the working fluid so that it may be returned a greater vertical distance from condenser to evaporator.

Koenig, D.R.

1981-02-11T23:59:59.000Z

76

Dust acoustic solitary and shock excitations in a Thomas-Fermi magnetoplasma  

SciTech Connect (OSTI)

The linear and nonlinear properties of dust-acoustic waves are investigated in a collisionless Thomas-Fermi magnetoplasma, whose constituents are electrons, ions, and negatively charged dust particles. At dust time scale, the electron and ion number densities follow the Thomas-Fermi distribution, whereas the dust component is described by the classical fluid equations. A linear dispersion relation is analyzed to show that the wave frequencies associated with the upper and lower modes are enhanced with the variation of dust concentration. The effect of the latter is seen more strongly on the upper mode as compared to the lower mode. For nonlinear analysis, we obtain magnetized Korteweg-de Vries (KdV) and Zakharov-Kuznetsov (ZK) equations involving the dust-acoustic solitary waves in the framework of reductive perturbation technique. Furthermore, the shock wave excitations are also studied by allowing dissipation effects in the model, leading to the Korteweg-de Vries-Burgers (KdVB) and ZKB equations. The analysis reveals that the dust-acoustic solitary and shock excitations in a Thomas-Fermi plasma are strongly influenced by the plasma parameters, e.g., dust concentration, dust temperature, obliqueness, magnetic field strength, and dust fluid viscosity. The present results should be important for understanding the solitary and shock excitations in the environments of white dwarfs or supernova, where dust particles can exist.

Rahim, Z.; Qamar, A. [Institute of Physics and Electronics, University of Peshawar, Peshawar 25000 (Pakistan); National Center for Physics (NCP) at QAU Campus, Shahdra Valley Road, Islamabad 44000 (Pakistan); Ali, S. [National Center for Physics (NCP) at QAU Campus, Shahdra Valley Road, Islamabad 44000 (Pakistan)

2014-07-15T23:59:59.000Z

77

Nonlethal Self-Defense, (Almost Entirely) Nonlethal Weapons, and the Rights to Keep and Bear Arms and Defend Life  

E-Print Network [OSTI]

apply to such nondeadly weapons. On balance, people’s rightAlmost Entirely) Nonlethal Weapons, and the Rights to KeepAlmost Entirely) Nonlethal Weapons, and the Rights To Keep

Volokh, Eugene

2010-01-01T23:59:59.000Z

78

FermiNews - November 10, 2000  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

3 | Friday, November 10, 2000 | Number 19 3 | Friday, November 10, 2000 | Number 19 In This Issue | FermiNews Main Page LHC Magnet: From Model to Prototype by Kurt Riesselmann Paul Mayer checks one of the leads to a coil prior to final assembly of the magnet Magnets are crucial components of every particle accelerator around the world. Like tracks guiding trains, they force charged particles to follow a path prescribed by magnetic forces. The higher the energy of the particles, the stronger the magnetic forces needed to steer them around a ring. The Large Hadron Collider, which will be the world's most powerful particle accelerator when finished in 2005, will feature the world's largest assembly of powerful magnets. Thousands of magnets will assure that protons, traveling at almost the speed of light, will stay on track as they zip around a 17-mile-long circular track at CERN, the European particle physics laboratory near Geneva, Switzerland.

79

I Fermi National Accelerator Laboratory I I  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

b b .?.? ... . . 1- \r I Fermi National Accelerator Laboratory I I FERMILAB-Cdnf-76 159 -EXP 2 020,000 2 02 2.000 I 1 (Submitted to the Neutrino I 9 76 Conference Aachen, Germany June 8r-13, -1976) * I 4 DISCLAIMER This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, make any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or

80

Momentum sharing in imbalanced Fermi systems  

E-Print Network [OSTI]

The atomic nucleus is composed of two different kinds of fermions, protons and neutrons. If the protons and neutrons did not interact, the Pauli exclusion principle would force the majority fermions (usually neutrons) to have a higher average momentum. Our high-energy electron scattering measurements using 12C, 27Al, 56Fe and 208Pb targets show that, even in heavy neutron-rich nuclei, short-range interactions between the fermions form correlated high-momentum neutron-proton pairs. Thus, in neutron-rich nuclei, protons have a greater probability than neutrons to have momentum greater than the Fermi momentum. This finding has implications ranging from nuclear few body systems to neutron stars and may also be observable experimentally in two-spin state, ultra-cold atomic gas systems.

O. Hen; M. Sargsian; L. B. Weinstein; E. Piasetzky; H. Hakobyan; D. W. Higinbotham; M. Braverman; W. K. Brooks; S. Gilad; K. P. Adhikari; J. Arrington; G. Asryan; H. Avakian; J. Ball; N. A. Baltzell; M. Battaglieri; A. Beck; S. May-Tal Beck; I. Bedlinskiy; W. Bertozzi; A. Biselli; V. D. Burkert; T. Cao; D. S. Carman; A. Celentano; S. Chandavar; L. Colaneri; P. L. Cole; V. Crede; A. DAngelo; R. De Vita; A. Deur; C. Djalali; D. Doughty; M. Dugger; R. Dupre; H. Egiyan; A. El Alaoui; L. El Fassi; L. Elouadrhiri; G. Fedotov; S. Fegan; T. Forest; B. Garillon; M. Garcon; N. Gevorgyan; Y. Ghandilyan; G. P. Gilfoyle; F. X. Girod; J. T. Goetz; R. W. Gothe; K. A. Griffioen; M. Guidal; L. Guo; K. Hafidi; C. Hanretty; M. Hattawy; K. Hicks; M. Holtrop; C. E. Hyde; Y. Ilieva; D. G. Ireland; B. I. Ishkanov; E. L. Isupov; H. Jiang; H. S. Jo; K. Joo; D. Keller; M. Khandaker; A. Kim; W. Kim; F. J. Klein; S. Koirala; I. Korover; S. E. Kuhn; V. Kubarovsky; P. Lenisa; W. I. Levine; K. Livingston; M. Lowry; H. Y. Lu; I. J. D. MacGregor; N. Markov; M. Mayer; B. McKinnon; T. Mineeva; V. Mokeev; A. Movsisyan; C. Munoz Camacho; B. Mustapha; P. Nadel-Turonski; S. Niccolai; G. Niculescu; I. Niculescu; M. Osipenko; L. L. Pappalardo; R. Paremuzyan; K. Park; E. Pasyuk; W. Phelps; S. Pisano; O. Pogorelko; J. W. Price; S. Procureur; Y. Prok; D. Protopopescu; A. J. R. Puckett; D. Rimal; M. Ripani; B. G. Ritchie; A. Rizzo; G. Rosner; P. Rossi; P. Roy; F. Sabatie; D. Schott; R. A. Schumacher; Y. G. Sharabian; G. D. Smith; R. Shneor; D. Sokhan; S. S. Stepanyan; S. Stepanyan; P. Stoler; S. Strauch; V. Sytnik; M. Taiuti; S. Tkachenko; M. Ungaro; A. V. Vlassov; E. Voutier; D. Watts; N. K. Walford; X. Wei; M. H. Wood; S. A. Wood; N. Zachariou; L. Zana; Z. W. Zhao; X. Zheng; I. Zonta

2014-11-29T23:59:59.000Z

Note: This page contains sample records for the topic "fermi reveals entire" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Momentum sharing in imbalanced Fermi systems  

DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

The atomic nucleus is composed of two different kinds of fermions, protons and neutrons. If the protons and neutrons did not interact, the Pauli exclusion principle would force the majority fermions (usually neutrons) to have a higher average momentum. Our high-energy electron scattering measurements using 12C, 27Al, 56Fe and 208Pb targets show that, even in heavy neutron-rich nuclei, short-range interactions between the fermions form correlated high-momentum neutron-proton pairs. Thus, in neutron-rich nuclei, protons have a greater probability than neutrons to have momentum greater than the Fermi momentum. This finding has implications ranging from nuclear few body systems to neutron stars and may also be observable experimentally in two-spin state, ultra-cold atomic gas systems.q

Hen, O.; Sargsian, M.; Weinstein, L. B.; Piasetzky, E.; Hakobyan, H.; Higinbotham, D. W.; Braverman, M.; Brooks, W. K.; Gilad, S.; Adhikari, K. P.; Arrington, J.; Asryan, G.; Avakian, H.; Ball, J.; Baltzell, N. A.; Battaglieri, M.; Beck, A.; Beck, S M -T; Bedlinskiy, I.; Bertozzi, W.; Biselli, A.; Burkert, V. D.; Cao, T.; Carman, D. S.; Celentano, A.; Chandavar, S.; Colaneri, L.; Cole, P. L.; Crede, V.; D'Angelo, A.; De Vita, R.; Deur, A.; Djalali, C.; Doughty, D.; Dugger, M.; Dupre, R.; Egiyan, H.; El Alaoui, A.; El Fassi, L.; Elouadrhiri, L.; Fedotov, G.; Fegan, S.; Forest, T.; Garillon, B.; Garcon, M.; Gevorgyan, N.; Ghandilyan, Y.; Gilfoyle, G. P.; Girod, F. X.; Goetz, J. T.; Gothe, R. W.; Griffioen, K. A.; Guidal, M.; Guo, L.; Hafidi, K.; Hanretty, C.; Hattawy, M.; Hicks, K.; Holtrop, M.; Hyde, C. E.; Ilieva, Y.; Ireland, D. G.; Ishkanov, B. I.; Isupov, E. L.; Jiang, H.; Jo, H. S.; Joo, K.; Keller, D.; Khandaker, M.; Kim, A.; Kim, W.; Klein, F. J.; Koirala, S.; Korover, I.; Kuhn, S. E.; Kubarovsky, V.; Lenisa, P.; Levine, W. I.; Livingston, K.; Lowry, M.; Lu, H. Y.; MacGregor, I. J.; Markov, N.; Mayer, M.; McKinnon, B.; Mineeva, T.; Mokeev, V.; Movsisyan, A.; Camacho, C. M.; Mustapha, B.; Nadel-Turonski, P.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Osipenko, M.; Pappalardo, L. L.; Paremuzyan, R.; Park, K.; Pasyuk, E.; Phelps, W.; Pisano, S.; Pogorelko, O.; Price, J. W.; Procureur, S.; Prok, Y.; Protopopescu, D.; Puckett, A. J.; Rimal, D.; Ripani, M.; Ritchie, B. G.; Rizzo, A.; Rosner, G.; Roy, P.; Rossi, P.; Sabatie, F.; Schott, D.; Schumacher, R. A.; Sharabian, Y. G.; Smith, G. D.; Shneor, R.; Sokhan, D.; Stepanyan, S. S.; Stepanyan, S.; Stoler, P.; Strauch, S.; Sytnik, V.; Taiuti, M.; Tkachenko, S.; Ungaro, M.; Vlassov, A. V.; Voutier, E.; Walford, N. K.; Wei, X.; Wood, M. H.; Wood, S. A.; Zachariou, N.; Zana, L.; Zhao, Z. W.; Zheng, X.; Zonta, I.

2014-10-30T23:59:59.000Z

82

Spinodal decomposition in polarized Fermi superfluids  

Science Journals Connector (OSTI)

We discuss the dynamics of phase separation through the process of spinodal decomposition in a Fermi superfluid with population imbalance. We discuss this instability first in terms of a phenomenological Landau theory. Working within the mean-field description at zero temperature, we then find the spinodal region in the phase diagram of polarization versus interaction strength and the spectrum of unstable modes in this region. After a quench, the spinodal decomposition starts from the Sarma state, which is a minimum of the free energy with respect to the order parameter at fixed density and polarization and a maximum at fixed chemical potentials. The possibility of observing nontrivial domain structures in current experiments with trapped atomic gases is discussed.

A. Lamacraft and F. M. Marchetti

2008-01-17T23:59:59.000Z

83

Full Hemisphere Fermi Surface Mapping Using A Novel Toroidal Electron Spectrometer  

SciTech Connect (OSTI)

An overview is provided of a next-generation toroidal angle-resolving photoemission spectrometer, currently in operation at BESSY II. The instrument features exceptional multi-detection in energy and angle, facilitating rapid full-hemisphere photoemission measurements. The instrument is ideal for band structure and Fermi Surface (FS) mapping using Angle Resolved Photoemission Spectroscopy (ARPES). Recent full-hemisphere FS measurements of a prototypical material, copper, reveal previously unseen fine structure due to lifetime broadening, demonstrating the high angular resolution and dense {kappa}-space sampling capabilities of the instrument.

Tadich, A. [Australian Synchrotron, Clayton, VIC 3168 (Australia); Department of Physics, La Trobe University, Bundoora, VIC 3086 (Australia); Riley, J.; Huwald, E.; Leckey, R. [Department of Physics, La Trobe University, Bundoora, VIC 3086 (Australia); Seyller, T.; Ley, L. [Institut fuer Technische Physik II, Universitaet Erlangen Nurnberg, 91058 Erlangen (Germany)

2010-06-23T23:59:59.000Z

84

SunShot Grand Challenge Highlights Ambitious Efforts along the Entire Solar  

Broader source: Energy.gov (indexed) [DOE]

SunShot Grand Challenge Highlights Ambitious Efforts along the SunShot Grand Challenge Highlights Ambitious Efforts along the Entire Solar Spectrum SunShot Grand Challenge Highlights Ambitious Efforts along the Entire Solar Spectrum June 13, 2012 - 5:30pm Addthis Energy Secretary Steven Chu gives the keynote address at the SunShot Grand Challenge Summit in Denver, Colorado. | Photo by Dennis Schroeder/NREL. Energy Secretary Steven Chu gives the keynote address at the SunShot Grand Challenge Summit in Denver, Colorado. | Photo by Dennis Schroeder/NREL. Ramamoorthy Ramesh Former Director, SunShot Initiative & Solar Energy Technologies Program What are the key facts? Today at the SunShot Grand Challenge Summit Energy Secretary Chu announced up to $8 million to support clean energy startups. Secretary Chu also announced a nationwide competition to drive down

85

Character of states near the Fermi level in (Ga,Mn)As: Impurity to valence band crossover RID E-6453-2010  

E-Print Network [OSTI]

We discuss the character of states near the Fermi level in Mn-doped GaAs, as revealed by a survey of dc transport and optical studies over a wide range of Mn concentrations. A thermally activated valence-band contribution to dc transport, a...

Jungwirth, T.; Sinova, Jairo; MacDonald, A. H.; Gallagher, B. L.; Novak, V.; Edmonds, K. W.; Rushforth, A. W.; Campion, R. P.; Foxon, C. T.; Eaves, L.; Olejnik, E.; Masek, J.; Yang, S-R Eric; Wunderlich, J.; Gould, C.; Molenkamp, L. W.; Dietl, T.; Ohno, H.

2007-01-01T23:59:59.000Z

86

Fermi-surface reconstruction and the origin of high-temperature superconductivity.  

SciTech Connect (OSTI)

In crystalline lattices, the conduction electrons form waves, known as Bloch states, characterized by a momentum vector k. The defining characteristic of metals is the surface in momentum space that separates occupied from unoccupied states. This 'Fermi' surface may seem like an abstract concept, but it can be measured and its shape can have profound consequences for the thermal, electronic, and magnetic properties of a material. In the presence of an external magnetic field B, electrons in a metal spiral around the field direction, and within a semiclassical momentum-space picture, orbit around the Fermi surface. Physical properties, such as the magnetization, involve a sum over these orbits, with extremal orbits on the Fermi surface, i.e., orbits with minimal or maximal area, dominating the sum [Fig. 1(a)]. Upon quantization, the resulting electron energy spectrum consists of Landau levels separated by the cyclotron energy, which is proportional to the magnetic field. As the magnetic field causes subsequent Landau levels to cross through the Fermi energy, physical quantities, such as the magnetization or resistivity, oscillate in response. It turns out that the period of these oscillations, when plotted as a function of 1/B, is proportional to the area of the extremal orbit in a plane perpendicular to the applied field [Fig. 1(b)]. The power of the quantum oscillation technique is obvious: By changing the field direction, one can map out the Fermi surface, much like a blind man feeling an elephant. The nature and topology of the Fermi surface in high-T{sub c} cuprates has been debated for many years. Soon after the materials were discovered by Bednorz and Mueller, it was realized that superconductivity was obtained by doping carriers into a parent insulating state. This insulating state appears to be due to strong electronic correlations, and is known as a Mott insulator. In the case of cuprates, the electronic interactions force the electrons on the copper ion lattice into a d{sup 9} configuration, with one localized hole in the 3d shell per copper site. Given the localized nature of this state, it was questioned whether a momentum-space picture was an appropriate description of the physics of the cuprates. In fact, this question relates to a long-standing debate in the physics community: Since the parent state is also an antiferromagnet, one can, in principle, map the Mott insulator to a band insulator with magnetic order. In this 'Slater' picture, Mott physics is less relevant than the magnetism itself. It is therefore unclear which of the two, magnetism or Mott physics, is more fundamentally tied to superconductivity in the cuprates. After twenty years of effort, definitive quantum oscillations that could be used to map the Fermi surface were finally observed in a high-temperature cuprate superconductor in 2007. This and subsequent studies reveal a profound rearrangement of the Fermi surface in underdoped cuprates. The cause of the reconstruction, and its implication for the origin of high-temperature superconductivity, is a subject of active debate.

Norman, M. R.; Materials Science Division

2010-01-01T23:59:59.000Z

87

The Life of Enrico Fermi | U.S. DOE Office of Science (SC)  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

The Life of Enrico Fermi The Life of Enrico Fermi The Enrico Fermi Award Fermi Award Home Nomination & Selection Guidelines Award Laureates Ceremony The Life of Enrico Fermi Contact Information The Enrico Fermi Award U.S. Department of Energy SC-2/Germantown Building 1000 Independence Ave., SW Washington, DC 20585 P: (301) 903-9395 E: fermi.award@science.doe.gov The Life of Enrico Fermi Print Text Size: A A A RSS Feeds FeedbackShare Page Enrico Fermi Click for a story about the photograph On December 2, 1942, Enrico Fermi and his team of scientists harnessed the atom and opened the door to new scientific and technological realms. His achievement allowed the U.S. to produce the atomic bomb that helped end World War II. Now, more than fifty years later, nuclear energy provides a significant part of the world's electrical power, and radioactive materials

88

The Enrico Fermi Award Homepage | U.S. DOE Office of Science (SC)  

Office of Science (SC) Website

Home Home The Enrico Fermi Award Fermi Award Home Nomination & Selection Guidelines Award Laureates Ceremony The Life of Enrico Fermi Contact Information The Enrico Fermi Award U.S. Department of Energy SC-2/Germantown Building 1000 Independence Ave., SW Washington, DC 20585 P: (301) 903-9395 E: fermi.award@science.doe.gov Print Text Size: A A A RSS Feeds FeedbackShare Page Enrico Fermi Enrico Fermi On November 16, 1954, President Eisenhower and the Atomic Energy Commission honored Enrico Fermi with a special award for his lifetime of accomplishments in physics and, in particular, for his vital role in the development of atomic energy. Shortly after receiving this honor, Enrico Fermi succumbed to cancer at the age of 53. The Enrico Fermi Presidential Award was subsequently established in 1956 as a memorial to the legacy of

89

Enrico Fermi Achieves First Self Sustain Nuclear Chain Reaction | National  

National Nuclear Security Administration (NNSA)

Enrico Fermi Achieves First Self Sustain Nuclear Chain Reaction | National Enrico Fermi Achieves First Self Sustain Nuclear Chain Reaction | National Nuclear Security Administration Our Mission Managing the Stockpile Preventing Proliferation Powering the Nuclear Navy Emergency Response Recapitalizing Our Infrastructure Continuing Management Reform Countering Nuclear Terrorism About Us Our Programs Our History Who We Are Our Leadership Our Locations Budget Our Operations Media Room Congressional Testimony Fact Sheets Newsletters Press Releases Speeches Events Social Media Video Gallery Photo Gallery NNSA Archive Federal Employment Apply for Our Jobs Our Jobs Working at NNSA Blog Home > About Us > Our History > NNSA Timeline > Enrico Fermi Achieves First Self Sustain Nuclear ... Enrico Fermi Achieves First Self Sustain Nuclear Chain Reaction

90

DOE - Office of Legacy Management -- Fermi National Accelerator Laboratory  

Office of Legacy Management (LM)

Fermi National Accelerator Fermi National Accelerator Laboratory - 016 FUSRAP Considered Sites Site: Fermi National Accelerator Laboratory (016) Designated Name: Alternate Name: Location: Evaluation Year: Site Operations: Site Disposition: Radioactive Materials Handled: Primary Radioactive Materials Handled: Radiological Survey(s): Site Status: This site began it's mission as a single-program research and development facility for the Atomic Energy Commission in 1972, when the first accelerator at the Laboratory began operations. The Laboratory¿s current mission is to conduct research in high energy physics under the direction of the Department of Energy's Office of Science. Clean-up of contamination at the site was completed in 1997. Also see Documents Related to Fermi National Accelerator Laboratory

91

Sobre a viagem de Enrico Fermi ao Brasil em 1934  

E-Print Network [OSTI]

Enrico Fermi was one of the greater physicists of the XX century. In 1934, he gave several lectures in Brazil. Invited by Theodoro Ramos to work in S\\~ao Paulo, he preferred to stay in Rome and went to the USA in 1938. However, Fermi recommended Gleb Wataghin to come in his place. Wataghin made history in Brazil, becoming one of the first Professors of the future S\\~ao Paulo University. Besides his relevance to the History of Science, Fermi eventually leaved an indelible mark on the creation and institutionalization of national scientific research due to the indication of Wataghin. Despite this fact, very little is known about Fermi's trip to Brazil. This work tries to reconstruct the fullest possible steps of the famous Italian physicist in our lands.

Caruso, Francisco

2014-01-01T23:59:59.000Z

92

Fermi surface behavior in the ABJM M2-brane theory  

E-Print Network [OSTI]

We calculate fermionic Green's functions for states of the three-dimensional ABJM M2-brane theory at large N using the gauge-gravity correspondence. We embed extremal black brane solutions in four-dimensional maximally supersymmetric gauged supergravity, obtain the linearized Dirac equations for each spin-1/2 mode that cannot mix with a gravitino, and solve these equations with infalling boundary conditions to calculate retarded Green's functions. For generic values of the chemical potentials, we find Fermi surfaces with universally non-Fermi liquid behavior, matching the situation for four-dimensional N=4 Super-Yang-Mills. Fermi surface singularities appear and disappear discontinuously at the point with all chemical potentials equal, reminiscent of a quantum critical point. One limit of parameter space has zero entropy at zero temperature, and fermionic fluctuations are perfectly stable inside an energy region around the Fermi surface. An ambiguity in the quantization of the fermions is resolved by supersym...

DeWolfe, Oliver; Rosen, Christopher

2014-01-01T23:59:59.000Z

93

Spin waves in a persistent spin-current Fermi liquid  

Science Journals Connector (OSTI)

We report two theoretical results for transverse spin waves, which arise in a system with a persistent spin current. Using Fermi liquid theory, we introduce a spin current in the ground state of a polarized or unpolarized Fermi liquid, and we derive the resultant spin waves using the Landau kinetic equation. The resulting spin waves have a q1 and q1/2 dispersion to leading order for the polarized and unpolarized systems, respectively.

J. D. Feldmann and K. S. Bedell

2010-06-14T23:59:59.000Z

94

5 Fermi 4/13/01  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

December 14, 2001 December 14, 2001 Number 20 f I N S I D E : 6 T h e F u t u r e , F i r s t D r a f t 8 Vi e w f r o m t h e To p 1 2 J u s t t h e R i g h t Ty p e Photo by Fred Ullrich What Do The Neighbors Think? 2 "Hello, I'm calling from Northern Illinois University. We are doing a study with people who live in northern Illinois about their opinions of science and the Fermi National Accelerator Laboratory (or Fermilab) located in Batavia. We are not selling anything. My questions will only take a very few minutes and there are no right or wrong answers. We are only interested in people's opinions." Early last spring, 1,033 of Fermilab's neighbors (about 45 percent of those who picked up the phone) responded to the invitation to tell what they thought about science, about Fermilab and about Fermilab's future. The laboratory's

95

FermiNews - January 19, 2001  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

January 19, 2001 | Number 1 January 19, 2001 | Number 1 In This Issue | FermiNews Main Page Protons Against Cancer by Kurt Riesselmann The Loma Linda Accelerator In contrast to biology and medicine, physics is not usually considered one of the life sciences. Yet basic research in physics makes critical, though often unsung, contributions to saving lives. Fermilab's role in cancer treatment is a case in point. Last month the Loma Linda Proton Treatment Center celebrated 10 years of treating cancer patients using particle beams from a compact proton accelerator completely designed and built at Fermilab. In the decade of the Center's operation, accelerator technology from Fermilab has provided cancer therapy at Loma Linda for more than 6000 patients from around the world. Cancer is the second leading cause of death in the United States, exceeded only by heart disease. Nearly five million lives have been lost to cancer since 1990, and physicians have diagnosed almost three times as many people with cancer during the same period of time. With people living longer than ever before, their chance of developing cancer is at an all-time high.

96

The Nuclear Thomas-Fermi Model  

DOE R&D Accomplishments [OSTI]

The statistical Thomas-Fermi model is applied to a comprehensive survey of macroscopic nuclear properties. The model uses a Seyler-Blanchard effective nucleon-nucleon interaction, generalized by the addition of one momentum-dependent and one density-dependent term. The adjustable parameters of the interaction were fitted to shell-corrected masses of 1654 nuclei, to the diffuseness of the nuclear surface and to the measured depths of the optical model potential. With these parameters nuclear sizes are well reproduced, and only relatively minor deviations between measured and calculated fission barriers of 36 nuclei are found. The model determines the principal bulk and surface properties of nuclear matter and provides estimates for the more subtle, Droplet Model, properties. The predicted energy vs density relation for neutron matter is in striking correspondence with the 1981 theoretical estimate of Friedman and Pandharipande. Other extreme situations to which the model is applied are a study of Sn isotopes from {sup 82}Sn to {sup 170}Sn, and the rupture into a bubble configuration of a nucleus (constrained to spherical symmetry) which takes place when Z{sup 2}/A exceeds about 100.

Myers, W. D.; Swiatecki, W. J.

1994-08-01T23:59:59.000Z

97

Labs at-a-Glance: Fermi National Accelerator Laboratory | U.S. DOE Office  

Office of Science (SC) Website

Fermi National Fermi National Accelerator Laboratory Laboratories Ames Laboratory Argonne National Laboratory Brookhaven National Laboratory Fermi National Accelerator Laboratory Lawrence Berkeley National Laboratory Oak Ridge National Laboratory Pacific Northwest National Laboratory Princeton Plasma Physics Laboratory SLAC National Accelerator Laboratory Thomas Jefferson National Accelerator Facility Laboratory Policy and Evaluation Safety, Security and Infrastructure Laboratory Science Highlights Contact Information Office of Science U.S. Department of Energy 1000 Independence Ave., SW Washington, DC 20585 P: (202) 586-5430 Labs at-a-Glance: Fermi National Accelerator Laboratory Print Text Size: A A A RSS Feeds FeedbackShare Page Fermi National Accelerator Laboratory Logo Visit the Fermi National Accelerator

98

Gamma-Ray Emission in Dissipative Pulsar Magnetospheres: From Theory to Fermi Observations  

E-Print Network [OSTI]

We compute the patterns of $\\gamma$-ray emission due to curvature radiation in dissipative pulsar magnetospheres. Our ultimate goal is to construct macrophysical models that are able to reproduce the observed $\\gamma$-ray light-curve phenomenology recently published in the Second Fermi Pulsar Catalog. We apply specific forms of Ohm's law on the open field lines using a broad range for the macroscopic conductivity values that result in solutions ranging, from near-vacuum to near Force-Free. Using these solutions, we generate model $\\gamma$-ray light curves by calculating realistic trajectories and Lorentz factors of radiating particles, under the influence of both the accelerating electric fields and curvature radiation-reaction. We further constrain our models using the observed dependence of the phase-lags between the radio and $\\gamma$-ray emission on the $\\gamma$-ray peak-separation. We perform a statistical comparison of our model radio-lag vs peak-separation diagram and the one obtained for the Fermi standard pulsars. We find that for models of uniform conductivity over the entire open magnetic field line region, agreement with observations favors higher values of this parameter. We find, however, significant improvement in fitting the data with models that employ a hybrid form of conductivity; specifically, infinite conductivity interior to the light-cylinder and high but finite conductivity on the outside. In these models the $\\gamma$-ray emission is produced in regions near the equatorial current sheet but modulated by the local physical properties. These models have radio-lags near the observed values and statistically best reproduce the observed light-curve phenomenology. Additionally, these models produce GeV photon cut-off energies.

Constantinos Kalapotharakos; Alice K. Harding; Demosthenes Kazanas

2014-07-27T23:59:59.000Z

99

Emission vs Fermi coordinates: applications to relativistic positioning systems  

E-Print Network [OSTI]

A 4-dimensional relativistic positioning system for a general spacetime is constructed by using the so called "emission coordinates". The results apply in a small region around the world line of an accelerated observer carrying a Fermi triad, as described by the Fermi metric. In the case of a Schwarzschild spacetime modeling the gravitational field around the Earth and an observer at rest at a fixed spacetime point, these coordinates realize a relativistic positioning system alternative to the current GPS system. The latter is indeed essentially conceived as Newtonian, so that it necessarily needs taking into account at least the most important relativistic effects through Post-Newtonian corrections to work properly. Previous results concerning emission coordinates in flat spacetime are thus extended to this more general situation. Furthermore, the mapping between spacetime coordinates and emission coordinates is completely determined by means of the world function, which in the case of a Fermi metric can be explicitly obtained.

Donato Bini; Andrea Geralico; Matteo Luca Ruggiero; Angelo Tartaglia

2008-09-05T23:59:59.000Z

100

Exact Green's Function and Fermi Surfaces from Conformal Gravity  

E-Print Network [OSTI]

We study the Dirac equation of a charged massless spinor on the general charged AdS black hole of conformal gravity. The equation can be solved exactly in terms of Heun's functions. We obtain the exact Green's function in the phase space (\\omega,k). This allows us to obtain Fermi surfaces for both Fermi and non-Fermi liquids. Our analytic results provide a more elegant approach of studying some strongly interacting fermionic systems not only at zero temperature, but also at any finite temperature. At zero temperature, we analyse the motion of the poles in the complex \\omega plane and obtain the leading order terms of the dispersion relation, expressed as the Laurent expansion of \\omega in terms of k. We illustrate new distinguishing features arising at the finite temperature. The Green's function with vanishing \\omega at finite temperature has a fascinating rich structure of spiked maxima in the plane of k and the fermion charge q.

H. Lu; Zhao-Long Wang

2012-10-16T23:59:59.000Z

Note: This page contains sample records for the topic "fermi reveals entire" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

Relaxation dynamics in a strongly coupled Fermi superfluid  

E-Print Network [OSTI]

The key feature of time-dependent dynamics in a paired Fermi superfluid is the presence of a large number of independent degrees of freedom---the pairing amplitudes of fermions with different momenta. We argue that useful prototypes of this dynamics come from D-brane constructions of string theory. Using a specific example of that kind, we identify the mechanism by which a strongly coupled Fermi superfluid relaxes to equilibrium; it involves a wave of excitation in the momentum space, propagating from the Fermi surface towards the ultraviolet. For a sudden quench induced by a change in the fermion coupling, we find that the relaxation occurs rapidly, over only a few oscillations of the quasiparticle gap.

Khlebnikov, S

2014-01-01T23:59:59.000Z

102

Off-shore wind power potential evaluation and economy analysis of entire Japan using GIS technology  

Science Journals Connector (OSTI)

Off-shore wind energy has been drawing interest recently. This research is focusing on the potential analysis of off-shore wind energy surrounding entire Japan coast using GIS technology. Base on the economy and environment assessment, this research is evaluating the current situation and forecasting on future of wind energy technology in Japan. In order to reduce the green-house gas emission, renewable energy (such as wind energy, solar energy, fuel cell) will gradually substitute can be installed the primary energy resource (such as coal, oil, scale gas). Based on GIS technique, wind power turbines in the surrounding area of Japanese coast-line. In the study, 2,000 kW rated wind turbines are considered for further installation. As the result of this study, we have determined that 108,067 in 330 places number of off-shore with annual generation of 180.0 TWh are expected. This is equal to 20% of annual total generated power of Japan in 2010. Wind speed 6 m/s or more of the coastline, the average cost of electricity is about generation cost is within 10 to 17 Japanese Yen/kWh and construction cost is within 139,445 Japanese Yen/kW to 240,366 Japanese Yen/kW.

Asifujiang Abudureyimu; Yoshiki Hayashi; Zulati Litifu; Ken Nagasaka

2012-01-01T23:59:59.000Z

103

Gamma-ray Spectral Evolution of NGC1275 Observed with Fermi-LAT  

E-Print Network [OSTI]

We report on a detailed investigation of the high-energy gamma-ray emission from NGC\\,1275, a well-known radio galaxy hosted by a giant elliptical located at the center of the nearby Perseus cluster. With the increased photon statistics, the center of the gamma-ray emitting region is now measured to be separated by only 0.46' from the nucleus of NGC1275, well within the 95% confidence error circle with radius ~1.5'. Early Fermi-LAT observations revealed a significant decade-timescale brightening of NGC1275 at GeV photon energies, with a flux about seven times higher than the one implied by the upper limit from previous EGRET observations. With the accumulation of one-year of Fermi-LAT all-sky-survey exposure, we now detect flux and spectral variations of this source on month timescales, as reported in this paper. The average >100 MeV gamma-ray spectrum of NGC1275 shows a possible deviation from a simple power-law shape, indicating a spectral cut-off around an observed photon energy of E = 42.2+-19.6 GeV, with...

Kataoka, J; Cheung, C C; Tosti, G; Cavazzuti, E; Celotti, A; Nishino, S; Fukazawa, Y; Thompson, D J; McConville, W F

2010-01-01T23:59:59.000Z

104

POLARIZATION AND VARIATION OF NEAR-INFRARED LIGHT FROM FERMI/LAT {gamma}-RAY SOURCES  

SciTech Connect (OSTI)

We present the results of our follow-up observation program of {gamma}-ray sources detected by the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope. Twenty-six blazars and thirty-nine sources unidentified at other wavelengths were targeted at the Infrared Survey Facility 1.4 m telescope equipped with the SIRIUS/SIRPOL imager and polarimeter. H-band magnitudes of the blazars at the epoch of 2010 December-2011 February are presented, which reveal clear flux variation since the Two Micron All Sky Survey observations and can be useful data for variation analyses of these objects in longer periods. We also find that nearly half of the {gamma}-ray blazars are highly (>10%) polarized in near-infrared wavelengths. Combining the polarization and variation properties, most ({approx}90%) of the blazars are clearly distinguished from all other types of objects at high Galactic latitudes. On the other hand, we find only one highly polarized and/or variable object in the fields of unidentified sources. This object is a counterpart of the optical variable source PQV1 J131553.00-073302.0 and the radio source NVSS J131552-073301 and is a promising candidate of new {gamma}-ray blazars. From the measured polarization and variation statistics, we conclude that most of the Fermi/LAT unidentified sources are not likely similar types of objects to the known {gamma}-ray blazars.

Fujiwara, M.; Matsuoka, Y. [Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602 (Japan); Ienaka, N., E-mail: matsuoka@a.phys.nagoya-u.ac.jp [Institute of Astronomy, The University of Tokyo, Osawa 2-21-1, Mitaka, Tokyo 181-0015 (Japan)

2012-10-01T23:59:59.000Z

105

The Spectral Energy Distribution of Fermi bright blazars  

E-Print Network [OSTI]

(Abridged) We have conducted a detailed investigation of the broad-band spectral properties of the \\gamma-ray selected blazars of the Fermi LAT Bright AGN Sample (LBAS). By combining our accurately estimated Fermi gamma-ray spectra with Swift, radio, infra-red, optical and other hard X-ray/gamma-ray data, collected within three months of the LBAS data taking period, we were able to assemble high-quality and quasi-simultaneous Spectral Energy Distributions (SED) for 48 LBAS blazars.The SED of these gamma-ray sources is similar to that of blazars discovered at other wavelengths, clearly showing, in the usual Log $\

Abdo, A A; Ajello, M; Axelsson, M; Baldini, L; Ballet, J; Barbiellini, G; Bastieri, D; Baughman, B M; Bechtol, K; Bellazzini, R; Berenji, B; Blandford, R D; Bloom, E D; Bonamente, E; Borgland, A; Bregeon, J; Brez, A; Brigida, M; Bruel, P; Burnett, T H; Buson, S; Caliandro, G A; Cameron, R A; Caraveo, P A; Casandjian, J M; Cavazzuti, E; Cecchi, C; Celik, O; Charles, E; Chaty, S; Chekhtman, A; Chiang, J; Ciprini, S; Claus, R; Cohen-Tanugi, J; Colafrancesco, S; Cominsky, L R; Conrad, J; Costamante, L; Cutini, S; Dermer, C D; de Angelis, A; de Palma, F; Digel, S W; Silva, E do Couto e; Drell, P S; Dubois, R; Dumora, D; Farnier, C; Favuzzi, C; Fegan, S J; Focke, W B; Fortin, P; Frailis, M; Fuhrmann, L; Fukazawa, Y; Funk, S; Fusco, P; Gargano, F; Gasparrini, D; Gehrels, N; Germani, S; Giebels, B; Giglietto, N; Giommi, P; Giordano, F; Glanzman, T; Godfrey, G; Grenier, I A; Grove, J E; Guillemot, L; Guiriec, S; Hadasch, D; Hanabata, Y; Harding, A K; Hayashida, M; Hays, E; Healey, S E; Horan, D; Hughes, R E; Itoh, R; Jackson, M S; Johannesson, G; Johnson, A S; Johnson, W N; Kadler, M; Kamae, T; Katagiri, H; Kataoka, J; Kawai, N; Kerr, M; Knodlseder, J; Kocian, M L; Kuss, M; Lande, J; Latronico, L; Longo, F; Loparco, F; Lott, B; Lovellette, M N; Lubrano, P; Madejski, G M; Makeev, A; Max-Moerbeck, W; Mazziotta, M N; McConville, W; McEnery, J E; Meurer, C; Michelson, P F

2009-01-01T23:59:59.000Z

106

Fermi velocity renormalization and dynamical gap generation in graphene  

E-Print Network [OSTI]

We study the renormalization of the Fermi velocity by the long-range Coulomb interactions between the charge carriers in the Dirac-cone approximation for the effective low-energy description of the electronic excitations in graphene at half filling. Solving the coupled system of Dyson-Schwinger equations for the dressing functions in the corresponding fermion propagator with various approximations for the particle-hole polarization we observe that Fermi velocity renormalization effects generally lead to a considerable increase of the critical coupling for dynamical gap generation and charge-density wave formation at the semimetal-insulator transition.

C. Popovici; C. S. Fischer; L. von Smekal

2015-01-12T23:59:59.000Z

107

Small-angle scattering in a marginal Fermi liquid  

Science Journals Connector (OSTI)

We study the magnetotransport properties of a model of small-angle scattering in a marginal Fermi liquid. Such a model has been proposed by Varma and Abrahams [Phys. Rev. Lett. 86, 4652 (2001)] to account for the anomalous temperature dependence of in-plane magnetotransport properties of the high-Tc cuprates. We study the resistivity, Hall angle, and magnetoresistance using both analytical and numerical techniques. We find that small-angle scattering only generates a difference in temperature dependence between the inverse Hall angle and the resistivity near particle-hole symmetric Fermi surfaces where the conventional Hall term vanishes. The magnetoresistance always shows Kohler’s rule behavior.

E. C. Carter and A. J. Schofield

2002-12-17T23:59:59.000Z

108

Photons from Heavy-Ion Collisions at Fermi Velocity  

E-Print Network [OSTI]

'I ~ (+l Ii & & .~ I + I I 'f Il I I PHYSICAL REVIEW C VOLUME 35, NUMBER 5 MAY 1987 Photons from heavy-ion collisions at Fermi velocity Che Ming Ko Center for Theoretical Physics, Physics Department and Cyclotron Institute, Texas Ad... from the first col- lision model are slightly diff'erent from theirs as we treat the distortion of the Fermi spheres more realistically. The angular distribution for 30-MeV photon emission is shown in Fig. 2. The solid curve is the calculated...

Ko, Che Ming; Alchelin, J.

1987-01-01T23:59:59.000Z

109

10p Fermi 7/2/99  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

C C o n s t r u c t i n g a L e g a c y 1 0 W i t h e r e l l S t a r t s Wo r k 1 2 R i g h t O n Ta r g e t 1 4 Ta l k o f t h e L a b Parting Words 2 F E R M I L A B A U. S. D E P A R T M E N T O F E N E R G Y L A B O R A T O R Y F N E E R W M S I Volume 22 Friday, July 2, 1999 Number 13 f Photo by Reidar Hahn Director John Peoples sat quietly as his life and career at Fermilab were toasted and roasted at the June 10 symposium held in his honor, but then his turn came to reflect on the best of his 10 years at the Laboratory. With his party about to get started, and barbecue and sparkling grape juice awaiting guests in the atrium, Peoples promised to keep his remarks Òdown to eight hours.Ó He launched into a narrative about the birth of the Recycler, and ended up paying his respects to the entire Fermilab staff. ÒIt would be nice to get a few things down for history,Ó he said.

110

Enrico Fermi Award Nominations | U.S. DOE Office of Science (SC)  

Office of Science (SC) Website

Enrico Fermi Enrico Fermi Award Nominations News Featured Articles Science Headlines 2014 2013 2012 2011 2010 2009 2008 2007 2006 2005 Presentations & Testimony News Archives Contact Information Office of Science U.S. Department of Energy 1000 Independence Ave., SW Washington, DC 20585 P: (202) 586-5430 12.04.12 Enrico Fermi Award Nominations The Office of Science is now accepting nominations for the 2013 Enrico Fermi Award. Print Text Size: A A A Subscribe FeedbackShare Page Call for Nominations - 2013 Enrico Fermi Award Nominations are sought for the 2013 Enrico Fermi Award beginning now through May 31, 2013. The outcome of the 2012 Fermi Award is anticipated to be announced soon. The Enrico Fermi Award is a Presidential award and one of the longest running and most prestigious science and technology awards given by the

111

Fermi National Accelerator Laboratory | U.S. DOE Office of Science...  

Office of Science (SC) Website

FY 2007 FNAL Assessment, please contact the Fermi Site Office. * Covers the first 9 months under the new contractor, Fermi Research Alliance, LLC. Last modified: 1032014 7:06:19...

112

Fermi liquid theory: A brief survey in memory of Gerald E. Brown  

E-Print Network [OSTI]

I present a brief review of Fermi liquid theory, and discuss recent work on Fermi liquid theory in dilute neutron matter and cold atomic gases. I argue that renewed interest in transport properties of quantum fluids provides fresh support for Landau's approach to Fermi liquid theory, which is based on kinetic theory rather than effective field theory and the renormalization group. I also discuss work on non-Fermi liquids, in particular dense quark matter.

Thomas Schaefer

2014-03-27T23:59:59.000Z

113

Energy Cost to Make a Hole in the Fermi Sea  

E-Print Network [OSTI]

The change in energy of an ideal Fermi gas when a local one-body potential is inserted into the system, or when the density is changed locally, are important quantities in condensed matter physics. We show that they can be rigorously bounded from below by a universal constant times the value given by the semiclassical approximation.

Rupert L. Frank; Mathieu Lewin; Elliott H. Lieb; Robert Seiringer

2011-02-07T23:59:59.000Z

114

General Properties of Fermi/LAT Active Galactic Nuclei  

E-Print Network [OSTI]

The Second Catalog of Blazars and other Active Galactic Nuclei detected by the Fermi/LAT (2LAC) includes about 1100 sources, 886 of which comprise the Clean Sample. The general properties of the different populations of sources classified according to the strength of their emission lines (FSRQs, BL Lacs) or the estimated position of the synchrotron peak are reviewed.

Lott, B; Cutini, S; Gasparrini, D; Dermer, C D

2012-01-01T23:59:59.000Z

115

Imaging nanoscale Fermi surface variations in an inhomogeneous superconductor  

E-Print Network [OSTI]

the highest energy electrons of the system reside, determine many material properties. Here we use a novel, the Fermi surface changes on nanometer length scales. Just as shifting tide lines expose variations of water of energy and position in the plane. By Fourier transforming constant energy slices of these surveys

Hudson, Eric

116

Determination of Fermi momentum using Compton scattering: An undergraduate experiment  

Science Journals Connector (OSTI)

A method to determine Fermi momentum in simple metals using Compton scattering of low?energy photons from a gamma ray source is described. Measurements can be done in room temperature and no special sample quality requirements are needed. The interpretation of the experiment shows also the close relation of the electronic quantities in position and momentum space.

S. Manninen; K. Hämäläinen; T. Paakkari

1988-01-01T23:59:59.000Z

117

A method for Fermi energy measurements A. Tsukernik,a)  

E-Print Network [OSTI]

due to the built-in field, which converts the diffusive regime of transport into thermionic emission on the analysis of thermionic emission and diffusion over a barrier with a built-in charge. The method can cannot be employed for Fermi energy measurements. As a result, the temperature dependence of thermionic

Luryi, Serge

118

Energy Cost to Make a Hole in the Fermi Sea  

Science Journals Connector (OSTI)

The change in energy of an ideal Fermi gas when a local one-body potential is inserted into the system, or when the density is changed locally, are important quantities in condensed matter physics. We show that they can be rigorously bounded from below by a universal constant times the value given by the semiclassical approximation.

Rupert L. Frank; Mathieu Lewin; Elliott H. Lieb; Robert Seiringer

2011-04-12T23:59:59.000Z

119

Secrets of superconductivity revealed  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Secrets of superconductivity revealed Secrets of superconductivity revealed Secrets of superconductivity revealed The superconducting material Cerium-Colbalt-Indium5 reveals new secrets about how superconductivity and magnetism can be related. January 3, 2014 Simon Gerber, first author of the publication on the superconducting properties of CeCoIn5 at the Morpheus instrument of the Spallation Neutron Source SINQ in Switzerland. (Photo: Paul Scherrer Institute/Markus Fischer) Simon Gerber, first author of the publication on the superconducting properties of CeCoIn5 at the Morpheus instrument of the Spallation Neutron Source SINQ in Switzerland. (Photo: Paul Scherrer Institute/Markus Fischer) "Superconductivity continues to give new surprises. As its secrets are revealed, we learn more about the quantum world of electrons and can begin

120

Secrets of superconductivity revealed  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Secrets of superconductivity revealed Secrets of superconductivity revealed Secrets of superconductivity revealed The superconducting material Cerium-Colbalt-Indium5 reveals new secrets about how superconductivity and magnetism can be related. January 3, 2014 Simon Gerber, first author of the publication on the superconducting properties of CeCoIn5 at the Morpheus instrument of the Spallation Neutron Source SINQ in Switzerland. (Photo: Paul Scherrer Institute/Markus Fischer) Simon Gerber, first author of the publication on the superconducting properties of CeCoIn5 at the Morpheus instrument of the Spallation Neutron Source SINQ in Switzerland. (Photo: Paul Scherrer Institute/Markus Fischer) "Superconductivity continues to give new surprises. As its secrets are revealed, we learn more about the quantum world of electrons and can begin

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121

Quantum melting of charge ice and non-Fermi-liquid behavior: An exact solution for the extended Falicov-Kimball model in the ice-rule limit  

E-Print Network [OSTI]

An exact solution is obtained for a model of itinerant electrons coupled to ice-rule variables on the tetrahedron Husimi cactus, an analogue of the Bethe lattice of corner-sharing tetrahedra. It reveals a quantum critical point with the emergence of non-Fermi-liquid behavior in melting of the "charge ice" insulator. The electronic structure is compared with the numerical results for the pyrochlore-lattice model to elucidate the physics of electron systems interacting with the tetrahedron ice rule.

Masafumi Udagawa; Hiroaki Ishizuka; Yukitoshi Motome

2010-06-04T23:59:59.000Z

122

Quantum melting of charge ice and non-Fermi-liquid behavior: An exact solution for the extended Falicov-Kimball model in the ice-rule limit  

E-Print Network [OSTI]

An exact solution is obtained for a model of itinerant electrons coupled to ice-rule variables on the tetrahedron Husimi cactus, an analogue of the Bethe lattice of corner-sharing tetrahedra. It reveals a quantum critical point with the emergence of non-Fermi-liquid behavior in melting of the "charge ice" insulator. The electronic structure is compared with the numerical results for the pyrochlore-lattice model to elucidate the physics of electron systems interacting with the tetrahedron ice rule.

Udagawa, Masafumi; Motome, Yukitoshi

2010-01-01T23:59:59.000Z

123

Secrets of superconductivity revealed  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

material Cerium-Colbalt-Indium5 reveals new secrets about how superconductivity and magnetism can be related. January 3, 2014 Simon Gerber, first author of the publication on the...

124

Fermi Site Office Homepage | U.S. DOE Office of Science (SC)  

Office of Science (SC) Website

Home Home Fermi Site Office (FSO) FSO Home About Current Projects Contract Management Environment, Safety and Health (ES&H) Resources Contact Information Fermi Site Office U.S. Department of Energy MS 118 P.O. Box 2000 Kirk Road and Pine Street Batavia, IL 60510 P: (630) 840-3281 F: (630) 840-3285 Fermi Site Office Pictured Right: Fermi view to the Northeast Fermi View to Northeast 1 of 2 Print Text Size: A A A RSS Feeds FeedbackShare Page The Fermi Site Office (FSO) is an organization within the U.S. Department of Energy's Office of Science with responsibility to oversee and manage the Management and Operating (M&O) contract for the Fermi National Accelerator Laboratory (FNAL) in Batavia, Illinois. FNAL is one of ten Office of Science Laboratories and is a single-program

125

The Centennial Celebrations of the Birth of the Physicist Enrico Fermi  

Office of Scientific and Technical Information (OSTI)

Centennial Celebrations of the Birth of the Physicist Enrico Fermi Centennial Celebrations of the Birth of the Physicist Enrico Fermi The Department of Energy's Fermi National Laboratory, the University of Chicago, and the University of Pisa in Italy will celebrate Enrico Fermi's 100th birthday on September 28 and 29 with symposiums on the universality of his physics and birthday cake. Enrico Fermi Enrico Fermi September 24-"The Italian navigator has landed" was the wartime-coded message announcing the successful first operation of a nuclear reactor on December 2, 1942. The expression refers to Columbus's exploration of continents previously unknown to Europeans, but also could apply to the exploration of another unknown continent, the atomic nucleus. The "Italian navigator" in this case was Enrico Fermi-the man who achieved the first

126

Fermi facts, fables: Colleagues and friends share memories  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Fermi facts, fables: Colleagues and friends Fermi facts, fables: Colleagues and friends share memories About Director's Welcome Organization Achievements Highlights Fact Sheets, Brochures & Other Documents Multimedia Library Visit Argonne Work with Argonne Contact us Nuclear Energy Why Nuclear Energy? Why are some people afraid of Nuclear Energy? How do nuclear reactors work? Cheaper & Safer Nuclear Energy Helping to Solve the Nuclear Waste Problem Nuclear Reactors Nuclear Reactors Early Exploration Training Reactors Basic and Applied Science Research LWR Technology Development BORAX-III lighting Arco, Idaho (Press Release) Heavy Water and Graphite Reactors Fast Reactor Technology Integral Fast Reactor Argonne Reactor Tree CP-1 70th Anniversary CP-1 70th Anniversary Argonne's Nuclear Science and Technology Legacy

127

Highly polarized Fermi gases across a narrow Feshbach resonance  

Science Journals Connector (OSTI)

We address the phase of a highly polarized Fermi gases across a narrow Feshbach resonance starting from the problem of a single down-spin fermion immersed in a Fermi sea of up spins. Both polaron and pairing states are considered using the variational wave function approach, and we find that the polaron-to-pairing transition will take place on the BCS side of the resonance, strongly in contrast to a wide resonance where the transition is located at the BEC side. For the pairing phase, we find the critical strength of the repulsive interaction between pairs above which the mixture of pairs and fermions will not phase separate. Therefore, nearby a narrow resonance, it is quite likely that magnetism can coexist with s-wave BCS superfluidity at large Zeeman fields, which is a remarkable property absent in conventional BCS superconductors (or fermion-pair superfluids).

Ran Qi and Hui Zhai

2012-04-13T23:59:59.000Z

128

Absorption by cold Fermi atoms in a harmonic trap  

E-Print Network [OSTI]

We study the absorption spectrum for a strongly degenerate Fermi gas confined in a harmonic trap. The spectrum is calculated using both the exact summation and also the Thomas-Fermi (TF) approximation. In the latter case, relatively simple analytical expressions are obtained for the absorption lineshape at large number of trapped atoms. At zero temperature, the approximated lineshape is characterized by a $(1-z^2)^{5/2}$ dependence which agrees well with the exact numerical calculations. At non-zero temperature, the spectrum becomes broader, although remains non-Gaussian as long as the fermion gas is degenerate. The changes in the trap frequency for an electronically excited atom can introduce an additional line broadening.

Gediminas Juzeliunas; Marius Masalas

2000-11-10T23:59:59.000Z

129

Neutrino events at IceCube and the Fermi bubbles  

Science Journals Connector (OSTI)

We discuss the possibility that the IceCube neutrino telescope might be observing the Fermi bubbles. If the bubbles discovered in gamma rays originate from accelerated protons, they should be strong emitters of high energy (?GeV) neutrinos. These neutrinos are detectable as showerlike or tracklike events at a Km3 neutrino observatory. For a primary cosmic ray flux with spectrum ?E?2.1 and cutoff energy at or above 10 PeV, the Fermi bubble flux substantially exceeds the atmospheric background, and could account for up to ?4–5 of the 28 events detected above ?30??TeV at IceCube. Running the detector for ?5–7 more years should be sufficient to discover this flux at high significance. For a primary cosmic ray flux with steeper spectrum, and/or lower cutoff energy, longer running times will be required to overcome the background.

Cecilia Lunardini; Soebur Razzaque; Kristopher T. Theodoseau; Lili Yang

2014-07-21T23:59:59.000Z

130

Polarized Fermi Condensates with Unequal Masses: Tuning the Tricritical Point  

Science Journals Connector (OSTI)

We consider a two-component atomic Fermi gas within a mean-field, single-channel model, where both the mass and population of each component are unequal. We show that the tricritical point at zero temperature evolves smoothly from the BEC to BCS side of the resonance as a function of mass ratio r. We find that the interior gap state proposed by Liu and Wilczek is always unstable to phase separation, while the breached pair state with one Fermi surface for the excess fermions exhibits differences in its density of states and pair correlation functions depending on which side of the resonance it lies. Finally, we show that, when r?3.95, the finite-temperature phase diagram of trapped gases at unitarity becomes topologically distinct from the equal mass system.

M. M. Parish; F. M. Marchetti; A. Lamacraft; B. D. Simons

2007-04-18T23:59:59.000Z

131

Instanton Effects in ABJM Theory from Fermi Gas Approach  

E-Print Network [OSTI]

We study the instanton effects of the ABJM partition function using the Fermi gas formalism. We compute the exact values of the partition function at the Chern-Simons levels k=1,2,3,4,6 up to N=44,20,18,16,14 respectively, and extract non-perturbative corrections from these exact results. Fitting the resulting non-perturbative corrections by their expected forms from the Fermi gas, we determine unknown parameters in them. After separating the oscillating behavior of the grand potential, which originates in the periodicity of the grand partition function, and the worldsheet instanton contribution, which is computed from the topological string theory, we succeed in proposing an analytical expression for the leading D2-instanton correction. Just as the perturbative result, the instanton corrections to the partition function are expressed in terms of the Airy function.

Hatsuda, Yasuyuki; Okuyama, Kazumi

2012-01-01T23:59:59.000Z

132

THE FIRST FERMI-LAT GAMMA-RAY BURST CATALOG  

SciTech Connect (OSTI)

In three years of observations since the beginning of nominal science operations in 2008 August, the Large Area Telescope (LAT) on board the Fermi Gamma-Ray Space Telescope has observed high-energy (?> 20 MeV) ?-ray emission from 35 gamma-ray bursts (GRBs). Among these, 28 GRBs have been detected above 100 MeV and 7 GRBs above ?20 MeV. The first Fermi-LAT catalog of GRBs is a compilation of these detections and provides a systematic study of high-energy emission from GRBs for the first time. To generate the catalog, we examined 733 GRBs detected by the Gamma-Ray Burst Monitor (GBM) on Fermi and processed each of them using the same analysis sequence. Details of the methodology followed by the LAT collaboration for the GRB analysis are provided. We summarize the temporal and spectral properties of the LAT-detected GRBs. We also discuss characteristics of LAT-detected emission such as its delayed onset and longer duration compared with emission detected by the GBM, its power-law temporal decay at late times, and the fact that it is dominated by a power-law spectral component that appears in addition to the usual Band model.

Ackermann, M. [Deutsches Elektronen Synchrotron DESY, D-15738 Zeuthen (Germany); Ajello, M. [Space Sciences Laboratory, 7 Gauss Way, University of California, Berkeley, CA 94720-7450 (United States); Asano, K. [Interactive Research Center of Science, Tokyo Institute of Technology, Meguro City, Tokyo 152-8551 (Japan); Axelsson, M. [Department of Astronomy, Stockholm University, SE-106 91 Stockholm (Sweden); Baldini, L. [Università di Pisa and Istituto Nazionale di Fisica Nucleare, Sezione di Pisa I-56127 Pisa (Italy); Ballet, J. [Laboratoire AIM, CEA-IRFU/CNRS/Université Paris Diderot, Service d'Astrophysique, CEA Saclay, 91191 Gif sur Yvette (France); Barbiellini, G. [Istituto Nazionale di Fisica Nucleare, Sezione di Trieste, I-34127 Trieste (Italy); Bastieri, D. [Istituto Nazionale di Fisica Nucleare, Sezione di Padova, I-35131 Padova (Italy); Bechtol, K.; Bloom, E. D. [W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States); Bellazzini, R.; Bregeon, J. [Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, I-56127 Pisa (Italy); Bhat, P. N. [Center for Space Plasma and Aeronomic Research (CSPAR), University of Alabama in Huntsville, Huntsville, AL 35899 (United States); Bissaldi, E. [Institut für Astro- und Teilchenphysik and Institut für Theoretische Physik, Leopold-Franzens-Universität Innsbruck, A-6020 Innsbruck (Austria); Bonamente, E. [Istituto Nazionale di Fisica Nucleare, Sezione di Perugia, I-06123 Perugia (Italy); Bonnell, J.; Brandt, T. J. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Bouvier, A., E-mail: nicola.omodei@stanford.edu, E-mail: giacomov@slac.stanford.edu [Santa Cruz Institute for Particle Physics, Department of Physics and Department of Astronomy and Astrophysics, University of California at Santa Cruz, Santa Cruz, CA 95064 (United States); and others

2013-11-01T23:59:59.000Z

133

Clustering of gamma-ray selected 2LAC Fermi Blazars  

E-Print Network [OSTI]

We present the first measurement of the projected correlation function of 485 gamma-ray selected Blazars, divided in 175 BLLacertae (BL Lacs) and 310 Flat Spectrum Radio Quasars (FSRQs) detected in the 2-year all-sky survey by Fermi-Large Area Telescope. We find that Fermi BL Lacs and FSRQs reside in massive dark matter halos (DMHs) with logMh=13.35+0.20/-0.14 and logMh = 13.40+0.15/-0.19 Msun/h, respectively, at low (z=0.4) and high (z =1.2) redshift. In terms of clustering properties, these results suggest that BL Lacs and FSRQs are similar objects residing in the same dense environment typical of galaxy groups, despite their different spectral energy distribution, power and accretion rate. We find no difference in the typical bias and hosting halo mass between Fermi Blazars and radio-loud AGN, supporting the unifcation scheme simply equating radio-loud objects with misaligned Blazar counterparts. This similarity in terms of typical environment they preferentially live in, suggests that Blazars preferential...

Allevato, Viola; Cappelluti, Nico

2014-01-01T23:59:59.000Z

134

CONSTRAINING THE HIGH-ENERGY EMISSION FROM GAMMA-RAY BURSTS WITH FERMI  

SciTech Connect (OSTI)

We examine 288 gamma-ray bursts (GRBs) detected by the Fermi Gamma-ray Space Telescope's Gamma-ray Burst Monitor (GBM) that fell within the field of view of Fermi's Large Area Telescope (LAT) during the first 2.5 years of observations, which showed no evidence for emission above 100 MeV. We report the photon flux upper limits in the 0.1-10 GeV range during the prompt emission phase as well as for fixed 30 s and 100 s integrations starting from the trigger time for each burst. We compare these limits with the fluxes that would be expected from extrapolations of spectral fits presented in the first GBM spectral catalog and infer that roughly half of the GBM-detected bursts either require spectral breaks between the GBM and LAT energy bands or have intrinsically steeper spectra above the peak of the {nu}F{sub {nu}} spectra (E{sub pk}). In order to distinguish between these two scenarios, we perform joint GBM and LAT spectral fits to the 30 brightest GBM-detected bursts and find that a majority of these bursts are indeed softer above E{sub pk} than would be inferred from fitting the GBM data alone. Approximately 20% of this spectroscopic subsample show statistically significant evidence for a cutoff in their high-energy spectra, which if assumed to be due to {gamma}{gamma} attenuation, places limits on the maximum Lorentz factor associated with the relativistic outflow producing this emission. All of these latter bursts have maximum Lorentz factor estimates that are well below the minimum Lorentz factors calculated for LAT-detected GRBs, revealing a wide distribution in the bulk Lorentz factor of GRB outflows and indicating that LAT-detected bursts may represent the high end of this distribution.

Ackermann, M. [Deutsches Elektronen Synchrotron DESY, D-15738 Zeuthen (Germany); Ajello, M.; Bechtol, K.; Blandford, R. D.; Bloom, E. D.; Borgland, A. W.; Bottacini, E.; Buehler, R.; Cameron, R. A.; Charles, E. [W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States); Baldini, L.; Bellazzini, R. [Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, I-56127 Pisa (Italy); Barbiellini, G. [Istituto Nazionale di Fisica Nucleare, Sezione di Trieste, I-34127 Trieste (Italy); Baring, M. G. [Department of Physics and Astronomy, Rice University, MS-108, P.O. Box 1892, Houston, TX 77251 (United States); Bonamente, E.; Cecchi, C. [Istituto Nazionale di Fisica Nucleare, Sezione di Perugia, I-06123 Perugia (Italy); Bouvier, A. [Santa Cruz Institute for Particle Physics, Department of Physics and Department of Astronomy and Astrophysics, University of California at Santa Cruz, Santa Cruz, CA 95064 (United States); Brigida, M. [Dipartimento di Fisica 'M. Merlin' dell'Universita e del Politecnico di Bari, I-70126 Bari (Italy); Buson, S. [Istituto Nazionale di Fisica Nucleare, Sezione di Padova, I-35131 Padova (Italy); Caliandro, G. A., E-mail: jchiang@slac.stanford.edu, E-mail: kocevski@slac.stanford.edu, E-mail: moretti@particle.kth.se, E-mail: connauv@uah.edu, E-mail: valerie@nasa.gov, E-mail: michael.briggs@nasa.gov [Institut de Ciencies de l'Espai (IEEE-CSIC), Campus UAB, E-08193 Barcelona (Spain); Collaboration: Fermi Large Area Telescope Team; Fermi Gamma-ray Burst Monitor Team; and others

2012-08-01T23:59:59.000Z

135

E-Print Network 3.0 - atic fermi egret Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Gamma-ray Burst Monitor (GBM) - Large Area Telescope (LAT) The High... -Energy Gamma-ray Sky Bursts, blazars, pulsars, and more Fermi LAT Searches ... Source: Maryland at...

136

Bose-Fermi solid and its quantum melting in a one-dimensional optical lattice  

Science Journals Connector (OSTI)

We investigate the quantum phase diagram of Bose-Fermi mixtures of ultracold dipolar particles trapped in one-dimensional optical lattices in the thermodynamic limit. With the presence of nearest-neighbor (NN) interactions, a long-ranged ordered crystalline phase (Bose-Fermi solid) is found stabilized in the limit of weak intersite tunneling (J). When J is increased, such a Bose-Fermi solid can be quantum melted into a Bose-Fermi liquid through different procedures, depending on whether the crystalline order is dominated by the NN interaction between fermions or bosons. These properties are qualitatively different from the classical picture of solid-liquid phase transition.

Bin Wang; Daw-Wei Wang; S. Das Sarma

2010-08-10T23:59:59.000Z

137

Fermi Site Office CX Determinations | U.S. DOE Office of Science...  

Office of Science (SC) Website

Fermi Site Office CX Determinations Safety and Security Policy (SSP) SSP Home About Frequently Used Resources Categorical Exclusion Determinations Continuity of Operations (COOP)...

138

Enrico Fermi and the First Self-Sustaining Nuclear Chain Reaction  

Office of Scientific and Technical Information (OSTI)

the first self-sustaining chain reaction and thereby initiated the controlled release of nuclear energy." Fermi's momentous accomplishments caused him to be recognized as one of...

139

PHOTOMETRICALLY TRIGGERED KECK SPECTROSCOPY OF FERMI BL LACERTAE OBJECTS  

SciTech Connect (OSTI)

We report on Keck spectra of 10 Fermi blazars. J0622+3326, previously unobserved, is shown to be a flat-spectrum radio quasar at redshift z = 1.062. The others are known BL Lac type objects that have resisted previous attempts to secure redshifts. Using a photometric monitoring campaign with the 0.76 m Katzman Automatic Imaging Telescope at Lick Observatory, we identified epochs when the relativistic jet emission was fainter than usual, thus triggering the Keck spectroscopy. This strategy gives improved sensitivity to stars and ionized gas in the host galaxy, thereby providing improved redshift constraints for seven of these sources.

Shaw, Michael S.; Romani, Roger W. [Department of Physics/KIPAC, Stanford University, Stanford, CA 94305 (United States); Filippenko, Alexei V.; Cenko, S. Bradley; Li, Weidong [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States)

2013-11-01T23:59:59.000Z

140

Isospin-mixing corrections for fp-shell Fermi transitions  

Science Journals Connector (OSTI)

Isospin-mixing corrections for superallowed Fermi transitions in fp-shell nuclei are computed within the framework of the shell model. The study includes three nuclei that are part of the set of nine accurately measured transitions as well as five cases that are expected to be measured in the future at radioactive-beam facilities. We also include some new calculations for C10. With the isospin-mixing corrections applied to the nine accurately measured ft values, the conserved-vector-current hypothesis and the unitarity condition of the Cabbibo-Kobayashi-Maskawa matrix are tested.

W. E. Ormand and B. A. Brown

1995-11-01T23:59:59.000Z

Note: This page contains sample records for the topic "fermi reveals entire" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

Zero sound modes of dilute Fermi gases with arbitrary spin  

Science Journals Connector (OSTI)

Motivated by the recent success of optical trapping of alkali-metal bosons, we have studied the zero sound modes of dilute Fermi gases with arbitrary spin-f, which are spin-S excitations (0<~S<~2f). The dispersion of the mode (S) depends on a single Landau parameter F(S), which is related to the scattering lengths of the system through a simple formula. Measurement of (even a subset of) these modes in finite magnetic fields will enable one to determine all the interaction parameters of the system.

S.-K. Yip and Tin-Lun Ho

1999-06-01T23:59:59.000Z

142

Quantum thermodynamic fluctuations of a chaotic Fermi-gas model  

E-Print Network [OSTI]

We investigate the thermodynamics of a Fermi gas whose single-particle energy levels are given by the complex zeros of the Riemann zeta function. This is a model for a gas, and in particular for an atomic nucleus, with an underlying fully chaotic classical dynamics. The probability distributions of the quantum fluctuations of the grand potential and entropy of the gas are computed as a function of temperature and compared, with good agreement, with general predictions obtained from random matrix theory and periodic orbit theory (based on prime numbers). In each case the universal and non--universal regimes are identified.

P. Leboeuf; A. G. Monastra

2003-02-28T23:59:59.000Z

143

The Entire Zoology Archive  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Zoology Archives Zoology Archives Zoology Archives, Since May 2000 Table of Contents: Bat Pets Insect Bites Earthworms and Soil Wren House Jumping Insects Killdeer Nesting Intolerance or Allergy to Milk Art and Mitosis Injured Animals Junebug Food Swans and Eggs Cat Eye Pupils Cob Web Origin Bee Sting Venom Appendix Function Stingrays Arm Pit Hair Function Deer Senses Tick Safety Palefaced Hornets and Risk Punnett Square Lettering Tick Types Hornet Behavior King Snakes Piercing Cartilidge American Kestrel Hawk Cottonmouths in Illinois Bees and flight Big Woodpeckers Crayfish Burrows June Bugs, Wasps and Hornets Waterdogs Moths and Metamorphosis Red Wasp Food Waterdogs Swan Eggs Dove Nesting Deer at Night Illinois Snakes Worm Teeth Housefly Napping Raising Ducks Scorpion Prevention Multiple Moths Young Birds

144

The Entire Engineering Archive  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Engineering Archives Engineering Archives Engineering Archives, Since November 1991 Table of Contents: Strongest geometric figure Geometric figures - bridges High school preparation for engineering Engineering fields and mathematics Future of mechanical engineering Absorbing energy in a crash Braking force of automobiles US fast-breeder policy Fusion energy to power Electricity generation Photovoltaic motors Variable speed motor Space plane Building on the moon Why does the Shuttle turn on launch? Gyroscopes Triangulation Magnets in speakers Speaker impedance Permanent magnet manufacture E/M interference FM modulation Pressure rise in pipe expansion Drag coefficient and Reynolds' Number Boundary layers Cavitation Is it more efficient to turn off fluorescent Uninterruptable power supply Electrical current

145

The Entire Chemistry Archive  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Chemistry Archives Chemistry Archives Chemistry Archives, Since November 1991 Table of Contents: When entropy = 0, does atomic motion stop? When H2O and methanol mix Heavy element names Radon Bee's wax CFC's and ozone depletion Solar cells and Phosphorous vs Chlorophyll B Aromaticity Hypercolor t-shirt Bonds for tie dye Soda POP General chemistry questions Tyndall Effect Silicon chips Molecules and cancer Acetylene safety Picric acid Buckyballs Piezoelectric Weak pennies Extracting fats Anti-oxidants Batteries & chemicals Hydrogen, can it be an isotope? Can soda conduct electricity? pH What is the biggest molecule? Smallest molecule Metallic zinc as catalyst Bond order in carbon bonds Packing of crystal structure Advantages, disadvantages of chloroform Coloring oil Free-radicals Acid-Base reaction

146

The Entire Botany Archive  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Botany Archives Botany Archives Botany Archives, Since May 2000 Table of Contents: Ginseng Caterpillars and Pin Oaks Seaweed and Nutrition Blue Leaves Walnut Problems Italian Trees Purple Plants Poplar Up-date European Tree Design Planting Magnolia Trees Schoolyard Plants Poplar Droppings Fungi Spores Woodland Adaptations Growing Lichen Apple Tree Maturity Horse Poison Plants Honeysuckle Poison Old Trees Leaking Popular Cottonwood Infestation Tulip Tree Seeds Bald Cypress Ecology Maple Recovery Leaf Minors Catalpa Problem Berm Enhancement Organic Gardening Ailing Burr Oak Damaged Cypress Tree Reed Ridding Berm Enhancement Tulip Tree Flowering Lichens Weed Seeds Plants at Night Kombu Seaweed Plants at Night Crab Grass Phloem Physiology Elm Disease Bark Thickness Poison Sumac Growing Fields Killing Pine Trees

147

Properties of Entire Functions  

E-Print Network [OSTI]

(z ) in RE mEOHEM (1-2). L*t (f ( 1) ( =1. 2, " ~ ) b q * of functions such that (1) f (z) (n=li2~ ~ ~ ~ ) is analytic in the region R, (2) the sequence converges uniformly to f(z) in RE Then f(z) is analytic in R, THEOREM (1-3) (Principle... of the argument). Let f(z) be analytic within and on a simple closed curve C, except possibly for poles. Suppose f(z) has no zeros on CD Then N-P=? arg f(z), 1 where N and P denote the number of zeros and polesi respectively, within Ci and M arg f(z) denotes...

Hunkler, Richard F

2012-06-07T23:59:59.000Z

148

The Entire Astronomy Archive  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

St@rl1ng St@rl1ng NEWTON's HOME PAGE Privacy Policy NEWTON, Ask A Scientist! Department of Energy Argonne National Laboratory Office of Science NEWTON's Homepage NEWTON's Homepage NEWTON Home Page NEWTON Teachers Visit Our Archives Ask A Question How To Ask A Question Question of the Week Our Expert Scientists Volunteer at NEWTON! Frequently Asked Questions Referencing NEWTON About NEWTON About Ask A Scientist Education At Argonne Astronomy Archives Astronomy Archives, Since November 1991 Table of Contents: Liquid mirror telescopes Astronomy instrument usage for object identification Condensed optics telescope repair Why do we not feel the Earth turning? Two high tides Turning Earth and distance to Sun Our speed through space Distance from center of Milky Way to Sun

149

Simulating strongly correlated electrons with a strongly interacting Fermi gas  

SciTech Connect (OSTI)

The quantum many-body physics of strongly-correlated fermions is studied in a degenerate, strongly- interacting atomic Fermi gas, first realized by our group with DOE support in 2002. This system, which exhibits strong spin pairing, is now widely studied and provides an important paradigm for testing predictions based on state-of-the-art many-body theory in fields ranging from nuclear matter to high temperature superfluidity and superconductivity. As the system is strongly interacting, both the superfluid and the normal fluid are nontrivial and of great interest. A central part of our program on Fermi gases is the connection between the study of thermodynamics, supported by DOE and the study of hydrodynamic transport, supported by NSF. This connection is especially interesting in view of a recent conjecture from the string theory community on the concept of nearly perfect normal fluids, which exhibit a minimum ratio of shear viscosity to entropy density in strongly-interacting, scale-invariant systems.

Thomas, John E. [North Carolina State University

2013-05-28T23:59:59.000Z

150

Spectral properties of Fermi/GBM gamma-ray bursts and the GeV emission detection rate with Fermi/LAT  

Science Journals Connector (OSTI)

With a sample of 58 Fermi/GBM GRBs detected before 2009 May, we compare the spectral properties of GBM GRBs with those detected by CGRO/BTASE and HETE-2. Our results show that the spectral index distributions ...

HouJun Lv; EnWei Liang; XiaoFeng Tong

2010-01-01T23:59:59.000Z

151

ccsd00000540 Production of Long-Lived Ultracold Li 2 Molecules from a Fermi gas  

E-Print Network [OSTI]

and sign of the scattering length. In bosonic samples, the collapse of Bose-Einstein condensates (BEC a Fermi gas J. Cubizolles 1 , T. Bourdel 1 , S. J. J. M. F. Kokkelmans 1 , G.V. Shlyapnikov 1;2;3 and C-bound Li2 molecules from a degenerate two component Fermi gas by sweeping a magnetic #12;eld across

152

PHYSICAL REVIEW A 87, 012703 (2013) Feshbach-molecule formation in a Bose-Fermi mixture  

E-Print Network [OSTI]

-degenerate Fermi gas of polar molecules would be an important step toward achieving novel quantum phases of matter molecules with a conversion efficiency as high as 45%. In the limit of fast magnetic sweeps and small of bosonic molecules from either Bose or Fermi gases. However, for quantum degenerate atom gas mixtures, we

Jin, Deborah

153

In-medium effects for nuclear matter in the Fermi energy domain D. Durand,1  

E-Print Network [OSTI]

In-medium effects for nuclear matter in the Fermi energy domain O. Lopez,1 D. Durand,1 G. Lehaut,1 of nuclear reactions in the Fermi energy domain. I. INTRODUCTION Transport properties in nuclear matter energy domain, transport features should exhibit the in- terplay between mean-field (nuclear degrees

Boyer, Edmond

154

Secretary Chu Names 2009 Enrico Fermi Award Winners | Department of Energy  

Broader source: Energy.gov (indexed) [DOE]

Names 2009 Enrico Fermi Award Winners Names 2009 Enrico Fermi Award Winners Secretary Chu Names 2009 Enrico Fermi Award Winners September 17, 2009 - 12:00am Addthis WASHINGTON, DC - US Energy Secretary Steven Chu has named Dr. John Bannister Goodenough and Dr. Siegfried S. Hecker as the winners of the Enrico Fermi Award, one of the most prestigious science and technology awards awarded by the U.S. Government. The Presidential award carries an honorarium of $375,000, which will be shared equally, and a gold medal. The award is administered on behalf of the White House by the U.S. Department of Energy. "The 2009 Enrico Fermi Award will go to two scientists who have selflessly devoted themselves to our nation's energy and national security challenges," said Secretary Chu. "These two individuals are pioneers in

155

Adaptation of the Landau-Migdal quasiparticle pattern to strongly correlated Fermi systems  

SciTech Connect (OSTI)

A quasiparticle pattern advanced in Landau's first article on Fermi-liquid theory is adapted to elucidate the properties of a class of strongly correlated Fermi systems characterized by a Lifshitz phase diagram featuring a quantum critical point (QCP) where the density of states diverges. The necessary condition for stability of the Landau Fermi-Liquid state is shown to break down in such systems, triggering a cascade of topological phase transitions that lead, without symmetry violation, to states with multi-connected Fermi surfaces. The end point of this evolution is found to be an exceptional state whose spectrum of single-particle excitations exhibits a completely flat portion at zero temperature. Analysis of the evolution of the temperature dependence of the single-particle spectrum yields results that provide a natural explanation of classical behavior of this class of Fermi systems in the QCP region.

Khodel, V. A. [Russian Research Centre Kurchatov Institute (Russian Federation); Clark, J. W. [Washington University, McDonnell Center for the Space Sciences and Department of Physics (United States); Zverev, M. V., E-mail: zverev@mbslab.kiae.ru [Russian Research Centre Kurchatov Institute (Russian Federation)

2011-09-15T23:59:59.000Z

156

Gamma-ray halo around the M31 galaxy as seen by the Fermi LAT  

E-Print Network [OSTI]

Theories of galaxy formation predict the existence of extended gas halo around spiral galaxies. If there are 10-100 nG magnetic fields at several ten kpc distances from the galaxies, extended galactic cosmic ray (CR) haloes could also exist. Galactic CRs could interact with the tenuous hot halo gas to produce observable $\\gamma$-rays. In this paper we have performed search for such a halo around the M31 galaxy -- the closest large spiral galaxy. Our analysis of 5.5 years of the Fermi LAT data revealed the presence of a spatially extended emission excess around M31. The data can be fitted using the simplest morphology of a uniformly bright circle. The best fit gave a 4.4$\\sigma$ significance for a $3^{\\circ}$ (40 kpc) halo with photon flux of $\\sim (1.9\\pm1.1)\\times 10^{-9} ~\\mathrm{cm^{-2}s^{-1}}$ and luminosity $(8.4\\pm4.6)\\times 10^{38} ~\\mathrm{erg~s^{-1}}$ in the energy range 0.3--100 GeV. The presence of such a halo compellingly shows that a 10-100 nG magnetic field should extend around M31 up to a 40 kp...

Pshirkov, M S; Postnov, K A

2015-01-01T23:59:59.000Z

157

GRB 110709A, 111117A, AND 120107A: FAINT HIGH-ENERGY GAMMA-RAY PHOTON EMISSION FROM FERMI-LAT OBSERVATIONS AND DEMOGRAPHIC IMPLICATIONS  

SciTech Connect (OSTI)

Launched on 2008 June 11, the Large Area Telescope (LAT) instrument on board the Fermi Gamma-ray Space Telescope has provided a rare opportunity to study high-energy photon emission from gamma-ray bursts (GRBs). Although the majority of such events (27) have been identified by the Fermi-LAT Collaboration, four were uncovered by using more sensitive statistical techniques. In this paper, we continue our earlier work by finding three more GRBs associated with high-energy photon emission, GRB 110709A, 111117A, and 120107A. To systematize our matched filter approach, a pipeline has been developed to identify these objects in nearly real time. GRB 120107A is the first product of this analysis procedure. Despite the reduced threshold for identification, the number of GRB events has not increased significantly. This relative dearth of events with low photon number prompted a study of the apparent photon number distribution. We find an extremely good fit to a simple power law with an exponent of -1.8 {+-} 0.3 for the differential distribution. As might be expected, there is a substantial correlation between the number of lower energy photons detected by the Gamma-ray Burst Monitor (GBM) and the number observed by LAT. Thus, high-energy photon emission is associated with some but not all of the brighter GBM events. Deeper studies of the properties of the small population of high-energy emitting bursts may eventually yield a better understanding of these entire phenomena.

Zheng Weikang; Akerlof, Carl W.; McKay, Timothy A. [Department of Physics, University of Michigan, 450 Church Street, Ann Arbor, MI 48109 (United States); Pandey, Shashi B. [Aryabhatta Research Institute of Observational Sciences, Manora Peak, Nainital 263129 (India); Zhang Binbin [Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States); Zhang Bing [Department of Physics and Astronomy, University of Nevada, Las Vegas, NV 89154 (United States); Sakamoto, Takanori, E-mail: zwk@umich.edu [Center for Research and Exploration in Space Science and Technology (CRESST), NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

2012-09-01T23:59:59.000Z

158

Calibration of the interaction energy between Bose and Fermi superfluids  

Science Journals Connector (OSTI)

In this paper we study the interaction energy in a mixture of Bose and Fermi superfluids realized in recent cold atom experiments. On the Bose-Einstein-condensate (BEC) side of a Feshbach resonance between fermionic atoms, this interaction energy can be directly related to the scattering length between a bosonic atom and a dimer composed of fermions. We calculate the atom-dimer scattering length from a three-body analysis with both a zero-range model and a separable model, including the van der Waals length scale, and we find significant deviation from the result given by a mean-field approach. We also find that the multiple scattering between atom and dimer can account for such a deviation. Our results provide a calibration to the mean-field interaction energy, which can be verified by measuring the shift of collective oscillation frequency.

Ren Zhang; Wei Zhang; Hui Zhai; Peng Zhang

2014-12-08T23:59:59.000Z

159

SLAC All Access: Fermi Gamma-ray Space Telescope  

SciTech Connect (OSTI)

Three hundred and fifty miles overhead, the Fermi Gamma-ray Space Telescope silently glides through space. From this serene vantage point, the satellite's instruments watch the fiercest processes in the universe unfold. Pulsars spin up to 700 times a second, sweeping powerful beams of gamma-ray light through the cosmos. The hyperactive cores of distant galaxies spew bright jets of plasma. Far beyond, something mysterious explodes with unfathomable power, sending energy waves crashing through the universe. Stanford professor and KIPAC member Roger W. Romani talks about this orbiting telescope, the most advanced ever to view the sky in gamma rays, a form of light at the highest end of the energy spectrum that's created in the hottest regions of the universe.

Romani, Roger

2013-05-31T23:59:59.000Z

160

FERMI LARGE AREA TELESCOPE OBSERVATIONS OF GRB 110625A  

SciTech Connect (OSTI)

Gamma-ray bursts (GRBs) that emit photons at GeV energies form a small but significant population of GRBs. However, the number of GRBs whose GeV-emitting period is simultaneously observed in X-rays remains small. We report {gamma}-ray observations of GRB 110625A using Fermi's Large Area Telescope in the energy range 100 MeV-20 GeV. Gamma-ray emission at these energies was clearly detected using data taken between 180 s and 580 s after the burst, an epoch after the prompt emission phase. The GeV light curve differs from a simple power-law decay, and probably consists of two emission periods. Simultaneous Swift X-Ray Telescope observations did not show flaring behaviors as in the case of GRB 100728A. We discuss the possibility that the GeV emission is the synchrotron self-Compton radiation of underlying ultraviolet flares.

Tam, P. H. T.; Kong, A. K. H. [Institute of Astronomy and Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Fan Yizhong, E-mail: phtam@phys.nthu.edu.tw [Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China)

2012-08-01T23:59:59.000Z

Note: This page contains sample records for the topic "fermi reveals entire" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

PROBING CURVATURE EFFECTS IN THE FERMI GRB 110920  

SciTech Connect (OSTI)

Curvature effects in gamma-ray bursts (GRBs) have long been a source of considerable interest. In a collimated relativistic GRB jet, photons that are off-axis relative to the observer arrive at later times than on-axis photons and are also expected to be spectrally softer. In this work, we invoke a relatively simple kinematic two-shell collision model for a uniform jet profile and compare its predictions to GRB prompt-emission data for observations that have been attributed to curvature effects such as the peak-flux-peak-frequency relation, i.e., the relation between the ?F{sub ?} flux and the spectral peak, E{sub pk} in the decay phase of a GRB pulse, and spectral lags. In addition, we explore the behavior of pulse widths with energy. We present the case of the single-pulse Fermi GRB 110920 as a test for the predictions of the model against observations.

Shenoy, A.; Maximon, L. C.; Dhuga, K. S.; Parke, W. C.; Maclachlan, G. A.; Eskandarian, Ali [Department of Physics, The George Washington University, Washington, DC 20052 (United States); Sonbas, E. [Department of Physics, University of Adiyaman, 02040 Adiyaman (Turkey); Dermer, C. [Space Science Division, Code 7653, Naval Research Laboratory, Washington, DC 20375 (United States); Bhat, P. N. [CSPAR, University of Alabama in Huntsville, Huntsville, AL 35805 (United States); Hakkila, J. [Department of Physics and Astronomy, College of Charleston, Charleston, SC 29424 (United States); Ukwatta, T. N., E-mail: ashwinsp469@gmail.com [Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States)

2013-11-20T23:59:59.000Z

162

Fermi GBM Observations of Terrestrial Gamma-ray Flashes  

SciTech Connect (OSTI)

Terrestrial Gamma-ray Flashes are short pulses of energetic radiation associated with thunderstorms and lightning. While the Gamma-ray Burst Monitor (GBM) on Fermi was designed to observe gamma-ray bursts, its large BGO detectors are excellent for observing TGFs. Using GBM, TGF pulses are seen to either be symmetrical or have faster rise time than fall times. Some TGFs are resolved into double, partially overlapping pulses. Using ground-based radio observations of lightning from the World Wide Lightning Location Network (WWLLN), TGFs and their associated lightning are found to be simultaneous to {approx_equal}40 {mu} s. The lightning locations are typically within 300 km of the sub-spacecraft point.

Briggs, Michael S. [CSPAR, NSSTC, 320 Sparkman Drive, Huntsville, AL 35805 (United States)

2011-09-21T23:59:59.000Z

163

Engineering superfluidity in Bose-Fermi mixtures of ultracold atoms  

Science Journals Connector (OSTI)

We investigate many-body phase diagrams of atomic boson-fermion mixtures loaded in the two-dimensional optical lattice. Bosons mediate an attractive, finite-range interaction between fermions, leading to fermion pairing phases of different orbital symmetries. Specifically, we show that by properly tuning atomic and lattice parameters it is possible to create superfluids with s-, p-, and d-wave pairing symmetry as well as spin and charge density wave phases. These phases and their stability are analyzed within the mean-field approximation for systems of K40-Rb87 and K40-Na23 mixtures. For the experimentally accessible regime of parameters, superfluids with unconventional fermion pairing have transition temperature around a percent of the Fermi energy.

D.-W. Wang; M. D. Lukin; E. Demler

2005-11-17T23:59:59.000Z

164

SLAC All Access: Fermi Gamma-ray Space Telescope  

ScienceCinema (OSTI)

Three hundred and fifty miles overhead, the Fermi Gamma-ray Space Telescope silently glides through space. From this serene vantage point, the satellite's instruments watch the fiercest processes in the universe unfold. Pulsars spin up to 700 times a second, sweeping powerful beams of gamma-ray light through the cosmos. The hyperactive cores of distant galaxies spew bright jets of plasma. Far beyond, something mysterious explodes with unfathomable power, sending energy waves crashing through the universe. Stanford professor and KIPAC member Roger W. Romani talks about this orbiting telescope, the most advanced ever to view the sky in gamma rays, a form of light at the highest end of the energy spectrum that's created in the hottest regions of the universe.

Romani, Roger

2014-06-24T23:59:59.000Z

165

Finite-size energy of non-interacting Fermi gases  

E-Print Network [OSTI]

We prove the asymptotics of the difference of the ground-state energies of two non-interacting $N$-particle Fermi gases on the half line of length $L$ in the thermodynamic limit up to order $1/L$. We are particularly interested in subdominant terms proportional to $1/L$, called finite-size energy. In the nineties Affleck and co-authors [Aff97, ZA97, AL94] claimed that the finite-size energy equals the decay exponent occuring in Anderson's orthogonality catastrophe. It turns out that the finite-size energy depends on the details of the thermodynamic limit and typically also includes a linear term in the scattering phase shift.

Martin Gebert

2014-06-14T23:59:59.000Z

166

Neutralino dark matter and the Fermi gamma-ray lines  

SciTech Connect (OSTI)

Motivated by recent claims of lines in the Fermi gamma-ray spectrum, we critically examine means of enhancing neutralino annihilation into neutral gauge bosons. The signal can be boosted while remaining consistent with continuum photon constraints if a new singlet-like pseudoscalar is present. We consider singlet extensions of the MSSM, focusing on the NMSSM, where a 'well-tempered' neutralino can explain the lines while remaining consistent with current constraints. We adopt a complementary numerical and analytic approach throughout in order to gain intuition for the underlying physics. The scenario requires a rich spectrum of light neutralinos and charginos leading to characteristic phenomenological signatures at the LHC whose properties we explore. Future direct detection prospects are excellent, with sizeable spin-dependent and spin-independent cross-sections.

Chalons, Guillaume [Institut für Theoretische Teilchenphysik, Karlsruhe Institute of Technology, Universität Karlsruhe Engesserstraße 7, 76128 Karlsruhe (Germany); Dolan, Matthew J.; McCabe, Christopher, E-mail: guillaume.chalons@kit.edu, E-mail: m.j.dolan@durham.ac.uk, E-mail: christopher.mccabe@durham.ac.uk [Institute for Particle Physics Phenomenology, Durham University, South Road, Durham, DH1 3LE (United Kingdom)

2013-02-01T23:59:59.000Z

167

Effective interaction approach to the Fermi hard-sphere system  

E-Print Network [OSTI]

The formalism based on correlated basis functions and the cluster expansion technique has been recently employed to derive an effective interaction from a realistic nuclear hamiltonian. To gauge the reliability of this scheme, we perform a systematic comparison between the results of its application to the Fermi hard-sphere system and the predictions obtained from low-density expansions, as well as from other many-body techniques. The analysis of a variety of properties, including the ground state energy, the effective mass and the momentum distribution, shows that the effective interaction approach is remarkably accurate, thus suggesting that it may be employed to achieve a consistent description of the structure and dynamics of nuclear matter in the density region relevant to astrophysical applications.

Angela Mecca; Alessandro Lovato; Omar Benhar; Artur Polls

2014-10-31T23:59:59.000Z

168

Effective interaction approach to the Fermi hard-sphere system  

E-Print Network [OSTI]

The formalism based on correlated basis functions and the cluster expansion technique has been recently employed to derive an effective interaction from a realistic nuclear hamiltonian. To gauge the reliability of this scheme, we perform a systematic comparison between the results of its application to the Fermi hard-sphere system and the predictions obtained from low-density expansions, as well as from other many-body techniques. The analysis of a variety of properties, including the ground state energy, the effective mass and the momentum distribution, shows that the effective interaction approach is remarkably accurate, thus suggesting that it may be employed to achieve a consistent description of the structure and dynamics of nuclear matter in the density region relevant to astrophysical applications.

Mecca, Angela; Benhar, Omar; Polls, Artur

2014-01-01T23:59:59.000Z

169

On the thermalization of the $?$-Fermi-Pasta-Ulam system  

E-Print Network [OSTI]

We study theoretically the original $\\alpha$-Fermi-Pasta-Ulam (FPU) system with $N=16,32$ and $64$ masses connected by a nonlinear quadratic spring. Our approach is based on resonant wave-wave interaction theory. We show that the route to thermalization consists of three stages. The first one is associated with non-resonant three-wave interactions. At this short time scale, the dynamics is reversible; this stage coincides with the observation of recurrent phenomena in numerical simulations of the $\\alpha$-FPU. On a larger time scale, exact four-wave resonant interactions start to take place; however, we find that all quartets are isolated, preventing a full mixing of energy in the spectrum and thermalization. The last stage corresponds to six-wave resonant interactions. Those are responsible for the energy equipartition recently observed in numerical simulations. A key role in our finding is played by the {\\it Umklapp} (flip over) resonant interactions, typical of discrete systems.

Miguel Onorato; Lara Vozella; Davide Proment; Yuri V. Lvov

2014-02-07T23:59:59.000Z

170

Common non-Fermi liquid phases in quantum impurity physics  

Science Journals Connector (OSTI)

We study correlated quantum impurity models that undergo a local quantum phase transition (QPT) from a strong coupling, Fermi liquid phase to a non-Fermi liquid phase with a globally doubly degenerate ground state. Our aim is to establish what can be shown exactly about such “local moment” (LM) phases, of which the permanent (zero-field) local magnetization is a hallmark, and an order parameter for the QPT. A description of the zero-field LM phase is shown to require two distinct self-energies, which reflect the broken symmetry nature of the phase and together determine the single self-energy of standard field theory. Distinct Friedel sum rules for each phase are obtained, via a Luttinger theorem embodied in the vanishing of appropriate Luttinger integrals. By contrast, the standard Luttinger integral is nonzero in the LM phase but found to have universal magnitude. A range of spin susceptibilites are also considered, including that corresponding to the local order parameter, whose exact form is shown to be RPA-like, and to diverge as the QPT is approached. Particular attention is given to the pseudogap Anderson model, including the basic physical picture of the transition, the low-energy behavior of single-particle dynamics, the quantum critical point itself, and the rather subtle effect of an applied local field. A two-level impurity model that undergoes a QPT (“singlet-triplet”) to an underscreened LM phase is also considered, for which we derive on general grounds some key results for the zero-bias conductance in both phases.

David E. Logan; Adam P. Tucker; Martin R. Galpin

2014-08-28T23:59:59.000Z

171

Deuterium-Tritium Pulse Propulsion with Hydrogen as Propellant and the Entire Spacecraft as a Gigavolt Capacitor for Ignition  

E-Print Network [OSTI]

A deuterium-tritium (DT) nuclear pulse propulsion concept for fast interplanetary transport is proposed utilizing almost all the energy for thrust and without the need for a large radiator: 1. By letting the thermonuclear micro-explosion take place in the center of a liquid hydrogen sphere with the radius of the sphere large enough to slow down and absorb the neutrons of the DT fusion reaction, heating the hydrogen to a fully ionized plasma at a temperature of ~ 105 K. 2. By using the entire spacecraft as a magnetically insulated gigavolt capacitor, igniting the DT micro-explosion with an intense GeV ion beam discharging the gigavolt capacitor, possible if the space craft has the topology of a torus.

Friedwardt Winterberg

2012-07-31T23:59:59.000Z

172

Strong-Coupling Theory for the Superfluidity of Bose-Fermi Mixtures  

Science Journals Connector (OSTI)

We develop a strong-coupling theory for the superfluidity of fermion pairing phase in a Bose-Fermi mixture. Dynamical screening, self-energy renormalization, and a pairing gap function are included self-consistently within the adiabatic limit (i.e., the phonon velocity is much smaller than the Fermi velocity). An analytical solution for the transition temperature (Tc) is derived within reasonable approximations. Using typical parameters of a K40-Rb87 mixture, we find that the calculated Tc is several times larger than that obtained in the weak coupling theory, and can be up to several percent of the Fermi temperature.

Daw-Wei Wang

2006-04-13T23:59:59.000Z

173

President Obama Names Scientists Bard and Sessler as Enrico Fermi Award  

Broader source: Energy.gov (indexed) [DOE]

President Obama Names Scientists Bard and Sessler as Enrico Fermi President Obama Names Scientists Bard and Sessler as Enrico Fermi Award Recipients President Obama Names Scientists Bard and Sessler as Enrico Fermi Award Recipients January 13, 2014 - 1:43pm Addthis NEWS MEDIA CONTACT (202)586-4940 WASHINGTON - President Obama has named Dr. Allen J. Bard and Dr. Andrew Sessler as recipients of the Enrico Fermi Award, one of the government's oldest and most prestigious awards for scientific achievement. The Presidential award carries an honorarium of $50,000, shared equally, and a medal. The award is administered on behalf of the White House by the U.S. Department of Energy. "Allen Bard and Andy Sessler have advanced the science and technology frontier throughout their distinguished careers and, in doing so, have contributed greatly to sustained US leadership in research and

174

Coordinate-Space Hartree-Fock-Bogoliubov Solvers for Super fluid Fermi  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Coordinate-Space Hartree-Fock-Bogoliubov Solvers for Super fluid Fermi Coordinate-Space Hartree-Fock-Bogoliubov Solvers for Super fluid Fermi Systems in Large Boxes Submitted by mkaczmar on March 29, 2013 - 12:53 Authors: Pei, J.C., Fann, G.I., Harrison, R.J., Nazarewicz, W., Hill, J., Galindo, D., Jia, J. The self-consistent Hartree-Fock-Bogoliubov problem in large boxes can be solved accurately in the coordinate space with the recently developed solvers HFB-AX (2D) and MADNESS-HFB (3D). This is essential for the description of superfluid Fermi systems with complicated topologies and significant spatial extend, such as fissioning nuclei, weakly-bound nuclei, nuclear matter in the neutron star rust, and ultracold Fermi atoms in elongated traps. The HFB-AX solver based on B-spline techniques uses a hybrid MPI and OpenMP programming model for parallel computation for

175

Converting an atomic Fermi gas into a long-lived molecular Bose gas  

Science Journals Connector (OSTI)

A quantum degenerate Fermi gas of 6Li atoms is converted into an ultracold gas of 6Li2 molecules using a Feshbach resonance. Up to 1.5 x 105 molecules are produced and trapped for up...

Strecker, Kevin E; Partridge, Guthrie B; Hulet, Randall G

176

Beam energy spread in FERMI@elettra gun and linac induced by intrabeam scattering  

E-Print Network [OSTI]

spread in FERMI@elettra gun and linac induced by intrabeamcathode area in the electron guns know in the literature asmost visible within the electron gun where the electron beam

Zholents, Alexander A

2008-01-01T23:59:59.000Z

177

Fermi Site Office CX Determinations | U.S. DOE Office of Science...  

Office of Science (SC) Website

IL 60439 P: (630) 252-2110 Larry Kelly U.S. Department of Energy 200 Administration Road Oak Ridge, TN 37830 P: (865) 576-0885 Categorical Exclusion (CX) Determinations Fermi Site...

178

Improved Measurement of the Muon Lifetime and Determination of the Fermi Constant  

E-Print Network [OSTI]

The MuLan collaboration has measured the lifetime of the positve muon to a precision of 1.0 parts per million. The Fermi constant is determined to a precision of 0.6 parts per million.

P. T. Debevec

2011-08-22T23:59:59.000Z

179

E-Print Network 3.0 - anisotropic fermi surfaces Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

PAGE1481 Classification Summary: the jump in the momentum distribution of such a gas at the Fermi surface deperlds on the filling factor v... of the position k on the...

180

Fermi-Energy-Dependent Structural Deformation of Chiral Single-Wall Carbon Nanotubes  

E-Print Network [OSTI]

In this work, we use an extended tight-binding approach for calculating the Fermi-energy dependence of the structural deformation of chiral single-wall carbon nanotubes (SWNTs). We show that, in general, nanotube strains ...

Vieira, Bruno G.?M.

Note: This page contains sample records for the topic "fermi reveals entire" from the National Library of EnergyBeta (NLEBeta).
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We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

Roton collective mode observed in a two-dimensional Fermi liquid  

E-Print Network [OSTI]

was the direct observation of the collective "phonon-roton" mode in liquid 4 He by neutron scattering, verifying in a Fermi liquid, obtained in a monolayer of liquid 3 He, studied by inelastic neutron scattering. We find

Boyer, Edmond

182

Gamma-ray bursts in the Swift-Fermi era: Confronting data with theory  

Science Journals Connector (OSTI)

With the prompt slewing capability of the X-ray and UV-optical telescopes onboard the Swift mission and with the gamma-ray large area telescope onboard the Fermi mission, gamma-ray bursts (GRBs) are now accessibl...

EnWei Liang

2010-01-01T23:59:59.000Z

183

Nonadiabatic phenomenology in small Fermi energy superconductors L. Pietronero a,b  

E-Print Network [OSTI]

Nonadiabatic phenomenology in small Fermi energy superconductors L. Pietronero a,b , E. Cappelluti hypothesis is of fundamental importance in the standard electron­phonon phenomenology, since it not only

Cappelluti, Emmanuele

184

Temperature dependence of the gaps of high-temperature superconductors in the Fermi-arc region  

Science Journals Connector (OSTI)

It is shown how in a high-temperature superconductor, the length of the Fermi arc can be obtained from the doping dependence of the pseudogap and the superconducting gap. In the momentum region spanned by the Fermi arc, the pseudogap temperature dependence follows that of the superconducting gap. The close interconnection of the two gaps suggests that they are both an essential part of the high-temperature superconductivity.

S. Hüfner and F. Müller

2008-07-23T23:59:59.000Z

185

Implementation of an iterative technique for a solution of the Thomas-Fermi equation  

E-Print Network [OSTI]

IMPLEMENTATION OF AN ITERATIVE TECHNIQUE FOR A SOLUTION OF THE THOMAS-FERMI EQUATION A Thesis by RAYMOND CALVERT FLAGG Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement for the degree... of MASTER OF SCIENCE August 1978 Major Subject: Mathematics IMPLEMENTATION OF AN ITERATIVE TECHNIQUE FOR A SOLUTION OF THE THOMAS-FERMI EQUATION A Thesis by RAYMOND CALVERT FLAGG Approved as to sryle and content by: (Chairman of Committeeee ( ead...

Flagg, Raymond Calvert

2012-06-07T23:59:59.000Z

186

Multiple-Vacancy Production in the Independent-Fermi-Particle Model  

E-Print Network [OSTI]

PHYSICAL REVIEW A VOLUME 29, NUMBER 6 JUNE 1984 Multiple-vacancy production in the independent-Fermi-particle model R. L. Becker Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 A. L. Ford and J. F. Reading Physics...-vacancy distributions in the independent-Fermi-particle collision model, based on the Hartree-Fock description of the target, which contains Pauli correlations. Our coupled- channels calculations employing these expressions have shown that the electron exchange terms...

Becker, R. L.; Ford, A. Lewis; Reading, John F.

1984-01-01T23:59:59.000Z

187

Viscosity and scale invariance in the unitary Fermi gas  

E-Print Network [OSTI]

We compute the shear viscosity of the unitary Fermi gas above the superfluid transition temperature, using a diagrammatic technique that starts from the exact Kubo formula. The formalism obeys a Ward identity associated with scale invariance which guarantees that the bulk viscosity vanishes identically. For the shear viscosity, vertex corrections and the associated Aslamazov-Larkin contributions are shown to be crucial to reproduce the full Boltzmann equation result in the high-temperature, low fugacity limit. The frequency dependent shear viscosity $\\eta(\\omega)$ exhibits a Drude-like transport peak and a power-law tail at large frequencies which is proportional to the Tan contact. The weight in the transport peak is given by the equilibrium pressure, in agreement with a sum rule due to Taylor and Randeria. Near the superfluid transition the peak width is of the order of $0.5 T_F$, thus invalidating a quasiparticle description. The ratio $\\eta/s$ between the static shear viscosity and the entropy density exhibits a minimum near the superfluid transition temperature whose value is larger than the string theory bound $\\hbar/(4\\pi k_B)$ by a factor of about seven.

Tilman Enss; Rudolf Haussmann; Wilhelm Zwerger

2010-07-30T23:59:59.000Z

188

Viscosity and scale invariance in the unitary Fermi gas  

SciTech Connect (OSTI)

We compute the shear viscosity of the unitary Fermi gas above the superfluid transition temperature, using a diagrammatic technique that starts from the exact Kubo formula. The formalism obeys a Ward identity associated with scale invariance which guarantees that the bulk viscosity vanishes identically. For the shear viscosity, vertex corrections and the associated Aslamazov-Larkin contributions are shown to be crucial to reproduce the full Boltzmann equation result in the high-temperature, low fugacity limit. The frequency dependent shear viscosity {eta}({omega}) exhibits a Drude-like transport peak and a power-law tail at large frequencies which is proportional to the Tan contact. The weight in the transport peak is given by the equilibrium pressure, in agreement with a sum rule due to Taylor and Randeria. Near the superfluid transition the peak width is of the order of 0.5T{sub F}, thus invalidating a quasiparticle description. The ratio {eta}/s between the static shear viscosity and the entropy density exhibits a minimum near the superfluid transition temperature whose value is larger than the string theory bound h/(4{pi}k{sub B}) by a factor of about seven.

Enss, Tilman, E-mail: Tilman.Enss@ph.tum.de [Technische Universitaet Muenchen, James-Franck-Strasse, D-85747 Garching (Germany); Haussmann, Rudolf [Fachbereich Physik, Universitaet Konstanz, D-78457 Konstanz (Germany); Zwerger, Wilhelm [Technische Universitaet Muenchen, James-Franck-Strasse, D-85747 Garching (Germany)

2011-03-15T23:59:59.000Z

189

Quantifying the Fermi paradox in the local Solar neighborhood  

E-Print Network [OSTI]

The Fermi paradox highlights the dichotomy between the lack of physical contact with other civilizations and the expectation that technological civilizations are assumed likely to evolve in many locations in the Milky Way galaxy, given the large number of planetary systems within this galaxy. Work by Landis and others has modeled this question in terms of percolation theory and cellular automata, using this method to parametrize our ignorance about possible other civilizations as a function of the probability of one system to colonize another, and the maximum number of systems reachable from each starting location (i.e. the degree in the network used for percolation). These models used a fixed lattice of sites to represent a stellar region, so the degree of all sites were identical. In this paper, the question is examined again, but instead of using a pre-determined lattice, the actual physical positions of all known star systems within 40 parsecs of the Solar System are used as percolation sites; in addition...

Cartin, Daniel

2014-01-01T23:59:59.000Z

190

Fermi-LAT observations of the Sagittarius B complex  

E-Print Network [OSTI]

Aims: We use 5 years of Fermi data towards the Galactic centre giant molecular cloud complex, Sagittarius B, to test questions of how well-mixed the Galactic component of cosmic rays are and the level of the cosmic-ray sea in different parts of the Galaxy. Methods:We use dust-opacity maps from the PLANCK satellite to obtain independent methods for background subtraction, and an estimate for the mass of the region. We then present high-quality spectrum of emission from 0.3 to 30 GeV, and obtain an estimate of the cosmic-ray spectrum from the regions. Results:We obtain an estimate of the mass of the region of $1.5\\pm0.2\\times10^7$ $\\rm m_{\\odot}$ using the PLANCK data, which agrees well with molecular-line derived estimates for the same region. We find the the gamma-ray flux from this region is well-fit with a cosmic-ray spectrum the same as that observed locally, with evidence of a small over-density at intermediate (1--10 GeV) energies. Conclusions:We conclude that the gamma-ray and cosmic-ray spectrum in the...

Yang, Rui-zhi; Aharonian, Felix

2014-01-01T23:59:59.000Z

191

Effective theory of Fermi pockets in fluctuating antiferromagnets  

Science Journals Connector (OSTI)

We describe fluctuating two-dimensional metallic antiferromagnets by transforming to a rotating reference frame in which the electron spin polarization is measured by its projections along the local antiferromagnetic order. This leads to a gauge-theoretic description of an “algebraic charge liquid” involving spinless fermions and a spin S=1/2 complex scalar. We propose a phenomenological effective lattice Hamiltonian which describes the binding of these particles into gauge-neutral, electronlike excitations, and describe its implications for the electron spectral function across the entire Brillouin zone. We discuss connections of our results to photoemission experiments in the pseudogap regime of the cuprate superconductors.

Yang Qi and Subir Sachdev

2010-03-19T23:59:59.000Z

192

Fermi bubbles as a source of cosmic rays above 10^{15} eV  

E-Print Network [OSTI]

Fermi bubbles are giant gamma-ray structures extended north and south of the Galactic center with characteristic sizes of order of 10 kpc recently discovered by Fermi Large Area Telescope. Good correlation between radio and gamma-ray emission in the region covered by Fermi bubbles implies the presence of high-energy electrons in this region. Since it is relatively difficult for relativistic electrons of this energy to travel all the way from the Galactic sources toward Fermi bubbles one can assume that they accelerated in-situ. The corresponding acceleration mechanism should also affect the distribution of the relativistic protons in the Galaxy. Since protons have much larger lifetimes the effect may even be observed near the Earth. In our model we suggest that Fermi bubbles are created by acceleration of electrons on series of shocks born due to periodic star accretions by supermassive black hole Sgr A*. We propose that hadronic CR within the "knee" of the observed CR spectrum are produced by Galactic supern...

Chernyshov, D O; Dogiel, V A; Ko, C M

2014-01-01T23:59:59.000Z

193

Fermi Site Office CX Determinations | U.S. DOE Office of Science (SC)  

Office of Science (SC) Website

Fermi Site Office CX Determinations Fermi Site Office CX Determinations Safety, Security and Infrastructure (SSI) SSI Home Facilities and Infrastructure Safeguards & Security Environment, Safety and Health (ES&H) Organization Chart .pdf file (82KB) Phone Listing .pdf file (129KB) SC HQ Continuity of Operations (COOP) Implementation Plan .pdf file (307KB) Categorical Exclusion Determinations SLI & SS Budget Contact Information Safety, Security and Infrastructure U.S. Department of Energy SC-31/Germantown Building 1000 Independence Ave., SW Washington, DC 20585 P: (301) 903-4097 F: (301) 903-7047 Categorical Exclusion (CX) Determinations Fermi Site Office CX Determinations Print Text Size: A A A RSS Feeds FeedbackShare Page Categorical Exclusion Determination Documents (CX Determinations): *

194

DOE Science Showcase - 2009 Enrico Fermi Award Winners | OSTI, US Dept of  

Office of Scientific and Technical Information (OSTI)

DOE Science Showcase - 2009 Enrico Fermi Award Winners DOE Science Showcase - 2009 Enrico Fermi Award Winners Find government research information related to 2009 Enrico Fermi Award Winners, including full-text technical reports, citations, project summaries and more. OSTI makes R&D information rapidly available to researchers and the public so that discovery can be accelerated. Dr. Goodenough's Research DOE R&D Accomplishments John B. Goodenough, Cathode Materials, and Rechargeable Lithium-ion Batteries Information Bridge Basic Research Needs for Electrical Energy Storage. Report of the Basic Energy Sciences Workshop on Electrical Energy Storage, April 2-4, 2007 Sign reversal of the MN-O bond compressibility in La{sub 1.2}Sr{sub 1.8}Mn{sub 2}O{sub 7} below T{sub C}: Exchange striction in the ferromagnetic state

195

U.S. Department of Energy, Secretary Chu Names 2009 Enrico Fermi Award  

Office of Scientific and Technical Information (OSTI)

September 17, 2009 September 17, 2009 Secretary Chu Names 2009 Enrico Fermi Award Winners University of Texas and Stanford University Professors to Share Presidential Award WASHINGTON, DC - US Energy Secretary Steven Chu has named Dr. John Bannister Goodenough and Dr. Siegfried S. Hecker as the winners of the Enrico Fermi Award, one of the most prestigious science and technology awards awarded by the U.S. Government. The Presidential award carries an honorarium of $375,000, which will be shared equally, and a gold medal. The award is administered on behalf of the White House by the U.S. Department of Energy. "The 2009 Enrico Fermi Award will go to two scientists who have selflessly devoted themselves to our nation's energy and national security challenges," said Secretary Chu. "These two individuals are

196

Appendices and Risk Assessment Spreadsheet Version No. Fermi National Accelerator Laboratory Engineering Manual  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Links to related documents referenced within the Engineering Manual: Links to related documents referenced within the Engineering Manual: Appendices and Risk Assessment Spreadsheet Version No. Fermi National Accelerator Laboratory Engineering Manual 07/10 Overview i Engineering at Fermilab 4 ii Purpose and Scope 5 iii Responsibilities 7 Fermilab Engineering Process 1 Requirements and Specifications 9 2 Engineering Risk Assessment 10 3 Requirements and Specifications Review 17 4 System Design 18 5 Engineering Design Review 21 6 Procurement and Implementation 23 7 Testing and Validation 26 8 Release to Operations 28 9 Final Documentation 29 Closing Thoughts 31 Appendices 33 Table of Contents Overview Fermi National Accelerator Laboratory Engineering Manual Page No. Version No. Fermi National Accelerator Laboratory Engineering Manual

197

Anomalous Fermi-Surface Dependent Pairing in a Self-Doped High-T(c) Superconductor  

SciTech Connect (OSTI)

We report the discovery of a self-doped multilayer high T{sub c} superconductor Ba{sub 2}Ca{sub 3}Cu{sub 4}O{sub 8}F{sub 2} (F0234) which contains distinctly different superconducting gap magnitudes along its two Fermi-surface sheets. While formal valence counting would imply this material to be an undoped insulator, it is a self-doped superconductor with a T{sub c} of 60 K, possessing simultaneously both electron- and hole-doped Fermi-surface sheets. Intriguingly, the Fermi-surface sheet characterized by the much larger gap is the electron-doped one, which has a shape disfavoring two electronic features considered to be important for the pairing mechanism: the van Hove singularity and the antiferromagnetic ({pi}/{alpha}, {pi}/{alpha}) scattering.

Chen, Yulin; Iyo, Akira; Yang, Wanli; Zhou, Xingjiang; Lu, Donghui; Eisaki, Hiroshi; Devereaux, Thomas P.; Hussain, Zahid; Shen, Z.-X.; /Stanford U., Phys. Dept. /SLAC,

2007-02-12T23:59:59.000Z

198

Matter-wave quantum dots and antidots in ultracold atomic Bose-Fermi mixtures  

Science Journals Connector (OSTI)

The properties of ultracold atomic Bose-Fermi mixtures in external potentials are investigated and the existence of gap solitons of Bose-Fermi mixtures in optical lattices demonstrated. Using a self-consistent approach we compute the energy spectrum and show that gap solitons can be viewed as matter-wave realizations of quantum dots and antidots with the bosonic density playing the role of trapping (expulsive) potential for the fermions. The fermionic states trapped in the condensate are shown to be at the bottom of the Fermi sea and therefore well protected from thermal decoherence. Energy levels, filling factors, and parameters’ dependence of gap soliton quantum dots are also calculated both numerically and analytically.

Mario Salerno

2005-12-02T23:59:59.000Z

199

Simultaneous Planck, Swift, and Fermi observations of X-ray and gamma-ray selected blazars  

E-Print Network [OSTI]

We present simultaneous Planck, Swift, Fermi, and ground-based data for 105 blazars belonging to three samples with flux limits in the soft X-ray, hard X-ray, and gamma-ray bands. Our unique data set has allowed us to demonstrate that the selection method strongly influences the results, producing biases that cannot be ignored. Almost all the BL Lac objects have been detected by Fermi-LAT, whereas ~40% of the flat-spectrum radio quasars (FSRQs) in the radio, soft X-ray, and hard X-ray selected samples are still below the gamma-ray detection limit even after integrating 27 months of Fermi-LAT data. The radio to sub-mm spectral slope of blazars is quite flat up to ~70GHz, above which it steepens to ~-0.65. BL Lacs have significantly flatter spectra than FSRQs at higher frequencies. The distribution of the rest-frame synchrotron peak frequency (\

Giommi, P; Lahteenmaki, A; Thompson, D J; Capalbi, M; Cutini, S; Gasparrini, D; Gonzalez-Nuevo, J; Leon-Tavares, J; Lopez-Caniego, M; Mazziotta, M N; Monte, C; Perri, M; Raino, S; Tosti, G; Tramacere, A; Verrecchia, F; Aller, H D; Aller, M F; Angelakis, E; Bastieri, D; Berdyugin, A; Bonaldi, A; Bonavera, L; Burigana, C; Burrows, D N; Buson, S; Cavazzuti, E; Chincarini, G; Colafrancesco, S; Costamante, L; Cuttaia, F; D'Ammando, F; de Zotti, G; Frailis, M; Fuhrmann, L; Galeotta, S; Gargano, F; Gehrels, N; Giglietto, N; Giordano, F; Giroletti, M; Keihanen, E; King, O; Krichbaum, T P; Lasenby, A; Lavonen, N; Lawrence, C R; Leto, C; Lindfors, E; Mandolesi, N; Massardi, M; Max-Moerbeck, W; Michelson, P F; Mingaliev, M; Natoli, P; Nestoras, I; Nieppola, E; Nilsson, K; Partridge, B; Pavlidou, V; Pearson, T J; Procopio, P; Rachen, J P; Readhead, A; Reeves, R; Reimer, A; Reinthal, R; Ricciardi, S; Richards, J; Riquelme, D; Saarinen, J; Sajina, A; Sandri, M; Savolainen, P; Sievers, A; Sillanpaa, A; Sotnikova, Y; Stevenson, M; Tagliaferri, G; Takalo, L; Tammi, J; Tavagnacco, D; Terenzi, L; Toffolatti, L; Tornikoski, M; Trigilio, C; Turunen, M; Umana, G; Ungerechts, H; Villa, F; Wu, J; Zacchei, A; Zensus, J A; Zhou, X

2011-01-01T23:59:59.000Z

200

Natural orbits of atomic Cooper pairs in a nonuniform Fermi gas  

E-Print Network [OSTI]

We examine the basic mode structure of atomic Cooper pairs in an inhomogeneous Fermi gas. Based on the properties of Bogoliubov quasi-particle vacuum, the single particle density matrix and the anomalous density matrix share the same set of eigenfunctions. These eigenfunctions correspond to natural pairing orbits associated with the BCS ground state. We investigate these orbits for a Fermi gas in a spherical harmonic trap, and construct the wave function of a Cooper pair in the form of Schmidt decomposition. The issue of spatial quantum entanglement between constituent atoms in a pair is addressed.

Y. H. Pong; C. K. Law

2006-05-08T23:59:59.000Z

Note: This page contains sample records for the topic "fermi reveals entire" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

Sensitivity of the FERMI Detectors to Gamma-Ray Bursts from Evaporating Primordial Black Holes (PBHs)  

E-Print Network [OSTI]

Primordial Black Holes (PBHs), which may have been created in the early Universe, are predicted to be detectable by their Hawking radiation. The Fermi Gamma-ray Space Telescope observatory offers increased sensitivity to the gamma-ray bursts produced by PBHs with an initial mass of $\\sim 5\\times 10^{14}$ g expiring today. PBHs are candidate progenitors of unidentified Gamma-Ray Bursts (GRBs) that lack X-ray afterglow. We propose spectral lag, which is the temporal delay between the high and low energy pulses, as an efficient method to identify PBH evaporation events with the Fermi Large Area Telescope (LAT).

T. N. Ukwatta; Jane H. MacGibbon; W. C. Parke; K. S. Dhuga; S. Rhodes; A. Eskandarian; N. Gehrels; L. Maximon; D. C. Morris

2010-03-23T23:59:59.000Z

202

Crossover from 2D to 3D in a Weakly Interacting Fermi Gas  

Science Journals Connector (OSTI)

We have studied the transition from two to three dimensions in a low temperature weakly interacting Li6 Fermi gas. Below a critical atom number N2D only the lowest transverse vibrational state of a highly anisotropic oblate trapping potential is occupied and the gas is two dimensional. Above N2D the Fermi gas enters the quasi-2D regime where shell structure associated with the filling of individual transverse oscillator states is apparent. This dimensional crossover is demonstrated through measurements of the cloud size and aspect ratio versus atom number.

P. Dyke; E. D. Kuhnle; S. Whitlock; H. Hu; M. Mark; S. Hoinka; M. Lingham; P. Hannaford; C. J. Vale

2011-03-11T23:59:59.000Z

203

Symmetry energy of hot nuclei in the relativistic Thomas-Fermi approximation  

E-Print Network [OSTI]

We develop a self-consistent description of hot nuclei within the relativistic Thomas--Fermi approximation using the relativistic mean-field model for nuclear interactions. The temperature dependence of the symmetry energy and other physical quantities of a nucleus are calculated by employing the subtraction procedure in order to isolate the nucleus from the surrounding nucleon gas. It is found that the symmetry energy coefficient of finite nuclei is significantly affected by the Coulomb polarization effect. We also examine the dependence of the results on nuclear interactions and make a comparison between the results obtained from relativistic and nonrelativistic Thomas-Fermi calculations.

Zhang, Z W; Hu, J N; Shen, H

2014-01-01T23:59:59.000Z

204

The Search for Dark Matter with the Fermi Gamma Ray Space Telescope  

SciTech Connect (OSTI)

The Fermi Gamma-Ray Space Telescope has been scanning the gamma ray sky since it was launched by NASA in June 2008 and has a mission lifetime goal of 10 years. Largely due to our particle physics heritage, one of the main physics topics being studied by the Fermi LAT Collaboration is the search for dark matter via indirect detection. My talk will review the progress of these studies, something on how the LAT detector enables them, and expectations for the future. I will discuss both gamma-ray and (electron + positron) searches for dark matter, and some resulting theoretical implications.

Bloom, Elliott (SLAC) [SLAC

2011-03-30T23:59:59.000Z

205

Fermi coordinates and modified Franklin transformation : A comparative study on rotational phenomena  

E-Print Network [OSTI]

Applying a relativistic rotational transformation to study and analyze rotational phenomena, instead of the rotational transformations based on consecutive Lorentz transformations and Fermi coordinates, leads to different predictions. In this article after a comparative study between Fermi metric of a uniformly rotating observer and the spacetime metric in a rotating frame obtained through the modified Franklin transformation, we consider rotational phenomena including transverse Doppler effect and Sagnac effect in both formalisms and compare their predictions. We also discuss length measurements in the two formalisms.

M. Nouri-Zonoz; H. Ramezani-Aval

2014-03-29T23:59:59.000Z

206

Fermi coordinates and modified Franklin transformation : A comparative study on rotational phenomena  

E-Print Network [OSTI]

Applying a relativistic rotational transformation to study and analyze rotational phenomena, instead of the rotational transformations based on consecutive Lorentz transformations and Fermi coordinates, leads to different predictions. In this article after a comparative study between Fermi metric of a uniformly rotating observer and the spacetime metric in a rotating frame obtained through the modified Franklin transformation, we consider rotational phenomena including transverse Doppler effect and Sagnac effect in both formalisms and compare their predictions. We also discuss length measurements in the two formalisms.

Nouri-Zonoz, M

2014-01-01T23:59:59.000Z

207

Chiral liquids in one dimension: A non-Fermi-liquid class of fixed points  

Science Journals Connector (OSTI)

We identify a non-Fermi-liquid class of fixed points describing the infrared behavior of interacting chiral fermions in one dimension. The thermodynamic properties and asymptotic correlation functions are characterized by universal exponents, which we determine by means of conformal and Bethe Ansatz techniques. The mechanism leading to the breakdown of Fermi-liquid theory is quite general and can be expected to be realized in systems with broken T invariance. As an example we study the edge states of interacting quantum Hall effect systems, where we calculate the universal NMR response.

Natan Andrei; Michael R. Douglas; Andrés Jerez

1998-09-15T23:59:59.000Z

208

Transport Anomalies and Marginal-Fermi-Liquid Effects at a Quantum Critical Point  

Science Journals Connector (OSTI)

The conductivity and the tunneling density of states of disordered itinerant electrons in the vicinity of a ferromagnetic transition at low temperature are discussed. Critical fluctuations lead to nonanalytic frequency and temperature dependencies that are distinct from the usual long-time tail effects in a disordered Fermi liquid. The crossover between these two types of behavior is proposed as an experimental check of recent theories of the quantum ferromagnetic critical behavior. In addition, the quasiparticle properties at criticality are shown to be those of a marginal Fermi liquid.

D. Belitz; T. R. Kirkpatrick; R. Narayanan; Thomas Vojta

2000-11-20T23:59:59.000Z

209

NREL researchers are the first to use a high-performance com-puting tool for a large-eddy simulation of an entire wind plant.  

E-Print Network [OSTI]

at least 50% wastepaper, including 10% post consumer waste. NREL Develops Simulations forWind Plant Power-eddy simulation of an entire wind plant. Researchers at the National Renewable Energy Laboratory's (NREL) National an existing wind plant, augmenting previous studies of wind plant subsets. Wind turbines extract energy from

210

Abstract--This paper revisits the possibility of controlling the power system entirely by means of price signals. It expands on  

E-Print Network [OSTI]

Abstract-- This paper revisits the possibility of controlling the power system entirely by means, be made to work with some caveats. Index Terms--Power system control, pricing, market design. I. An important extension of the work of Schweppe was provided by William Hogan, who in 1992 introduced

211

Fermi-LAT Discovery of GeV Gamma-ray Emission from the Young Supernova Remnant Cassiopeia A  

SciTech Connect (OSTI)

We report on the first detection of GeV high-energy gamma-ray emission from a young supernova remnant with the Large Area Telescope aboard the Fermi Gamma-ray Space Telescope. These observations reveal a source with no discernible spatial extension detected at a significance level of 12.2{sigma} above 500 MeV at a location that is consistent with the position of the remnant of the supernova explosion that occurred around 1680 in the Cassiopeia constellation - Cassiopeia A. The gamma-ray flux and spectral shape of the source are consistent with a scenario in which the gamma-ray emission originates from relativistic particles accelerated in the shell of this remnant. The total content of cosmic rays (electrons and protons) accelerated in Cas A can be estimated as W{sub CR} {approx_equal} (1-4) x 10{sup 49} erg thanks to the well-known density in the remnant assuming that the observed gamma-ray originates in the SNR shell(s). The magnetic field in the radio-emitting plasma can be robustly constrained as B {ge} 0.1 mG, providing new evidence of the magnetic field amplification at the forward shock and the strong field in the shocked ejecta.

Abdo, A.A.

2011-08-19T23:59:59.000Z

212

FERMI-LAT DISCOVERY OF GeV GAMMA-RAY EMISSION FROM THE YOUNG SUPERNOVA REMNANT CASSIOPEIA A  

SciTech Connect (OSTI)

We report on the first detection of GeV high-energy gamma-ray emission from a young supernova remnant (SNR) with the Large Area Telescope aboard the Fermi Gamma-ray Space Telescope. These observations reveal a source with no discernible spatial extension detected at a significance level of 12.2{sigma} above 500 MeV at a location that is consistent with the position of the remnant of the supernova explosion that occurred around 1680 in the Cassiopeia constellation-Cassiopeia A (Cas A). The gamma-ray flux and spectral shape of the source are consistent with a scenario in which the gamma-ray emission originates from relativistic particles accelerated in the shell of this remnant. The total content of cosmic rays (electrons and protons) accelerated in Cas A can be estimated as W {sub CR} {approx_equal} (1-4) x 10{sup 49} erg thanks to the well-known density in the remnant assuming that the observed gamma ray originates in the SNR shell(s). The magnetic field in the radio-emitting plasma can be robustly constrained as B {>=} 0.1 mG, providing new evidence of the magnetic field amplification at the forward shock and the strong field in the shocked ejecta.0.

Abdo, A. A. [Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States); Ackermann, M.; Ajello, M.; Allafort, A.; Bechtol, K.; Berenji, B.; Blandford, R. D.; Bloom, E. D.; Borgland, A. W. [W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States); Baldini, L.; Bellazzini, R.; Bregeon, J.; Brez, A. [Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, I-56127 Pisa (Italy); Ballet, J. [Laboratoire AIM, CEA-IRFU/CNRS/Universite Paris Diderot, Service d'Astrophysique, CEA Saclay, 91191 Gif sur Yvette (France); Barbiellini, G. [Istituto Nazionale di Fisica Nucleare, Sezione di Trieste, I-34127 Trieste (Italy); Baring, M. G. [Department of Physics and Astronomy, Rice University, MS-108, P.O. Box 1892, Houston, TX 77251 (United States); Bastieri, D. [Istituto Nazionale di Fisica Nucleare, Sezione di Padova, I-35131 Padova (Italy); Baughman, B. M. [Department of Physics, Center for Cosmology and Astro-Particle Physics, The Ohio State University, Columbus, OH 43210 (United States); Bonamente, E. [Istituto Nazionale di Fisica Nucleare, Sezione di Perugia, I-06123 Perugia (Italy); Brigida, M. [Dipartimento di Fisica 'M. Merlin' dell'Universita e del Politecnico di Bari, I-70126 Bari (Italy)], E-mail: funk@slac.stanford.edu, E-mail: uchiyama@slac.stanford.edu (and others)

2010-02-10T23:59:59.000Z

213

Detection of significant cm to sub-mm band radio and gamma-ray correlated variability in Fermi bright blazars  

E-Print Network [OSTI]

The exact location of the gamma-ray emitting region in blazars is still controversial. In order to attack this problem we present first results of a cross-correlation analysis between radio (11 cm to 0.8 mm wavelength, F-GAMMA program) and gamma-ray (0.1-300 GeV) ~ 3.5 year light curves of 54 Fermi-bright blazars. We perform a source stacking analysis and estimate significances and chance correlations using mixed source correlations. Our results reveal: (i) the first highly significant multi-band radio and gamma-ray correlations (radio lagging gamma rays) when averaging over the whole sample, (ii) average time delays (source frame: 76+/-23 to 7+/-9 days), systematically decreasing from cm to mm/sub-mm bands with a frequency dependence tau_r,gamma (nu) ~ nu^-1, in good agreement with jet opacity dominated by synchrotron self-absorption, (iii) a bulk gamma-ray production region typically located within/upstream of the 3 mm core region (tau_3mm,gamma=12+/-8 days), (iv) mean distances between the region of gamma-...

Fuhrmann, L; Chiang, J; Angelakis, E; Zensus, J A; Nestoras, I; Krichbaum, T P; Ungerechts, H; Sievers, A; Pavlidou, V; Readhead, A C S; Max-Moerbeck, W; Pearson, T J

2014-01-01T23:59:59.000Z

214

Suzaku Observation of the Fermi Cygnus Cocoon: Search for a Signature of Young Cosmic-Ray Electrons  

E-Print Network [OSTI]

The origin of Galactic cosmic rays remains unconfirmed, but promising candidates for their sources are found in star-forming regions. We report a series of X-ray observations, with Suzaku, toward the nearby star-forming region of Cygnus X. They aim at comparing diffuse X-ray emissions on and off the $\\gamma$-ray cocoon of hard cosmic rays revealed by Fermi LAT. After excluding point sources and small-scale structures and subtracting the non-X-ray and cosmic X-ray backgrounds, the 2--10~keV X-ray intensity distribution is found to monotonically decrease with increasing Galactic latitude. This indicates that most of the extended emission detected by Suzaku originates from the Galactic ridge. In two observations, we derive upper limits of $3.4 \\times 10^{-8}~{\\rm erg~s^{-1}~cm^{-2}~sr^{-1}}$ and $1.3 \\times 10^{-8}~{\\rm erg~s^{-1}~cm^{-2}~sr^{-1}}$ to X-ray emission in the 2--10 keV range from the gamma-ray cocoon. These limits exclude the presence of cosmic-ray electrons with energies above about 50 TeV at a fl...

Mizuno, T; Takahashi, H; Hayashi, K; Yamazaki, R; Grenier, I; Tibaldo, L

2015-01-01T23:59:59.000Z

215

The Fermi Large Area gamma ray Telescope and the current searches for dark matter in space  

E-Print Network [OSTI]

production [6],[7] [9]. The temptation to claim the discovery of dark matter is strongThe Fermi Large Area gamma ray Telescope and the current searches for dark matter in space Aldo Gamma-ray Space Telescope, has detected the largest amount of gamma rays, in the 20MeV 300GeV energy

Morselli, Aldo

216

The Fermi And Gamov-Teller {beta}-Decay Excitations Of The Scissors Mode 1+ States  

SciTech Connect (OSTI)

In this study, the allowed Gamov-Teller (GT) and Fermi {beta} transitions from 1+-state of the odd-odd nuclei to 1+-states are considered. Calculation of the {beta} transition matrix elements is performed in the phonon description and an analytical expressions for MF and MGT matrix elements are obtained for the first time.

Yildirm, Z.; Ertugral, F.; Kuliev, A. A. [Sakarya University, Physics Department, Adapazari (Turkey); Guliyev, E. [Institute of Physics, National Academy of Sciences, Baku (Azerbaijan)

2007-04-23T23:59:59.000Z

217

Establishing Site X: Letter, Arthur H. Compton to Enrico Fermi, September 14, 1942  

DOE R&D Accomplishments [OSTI]

This letter from Compton to Fermi describes developments bearing on the establishment of site X (which, as of the letter date, is definitely determined as at the Tennessee Valley) for the construction of a pile and associated pilot plant buildings, describes the situation as of the letter date, and offers counsel as to how to proceed.

Compton, A. H.

1942-09-00T23:59:59.000Z

218

ccsd00001419, Coherence and correlation properties of a one-dimensional attractive Fermi gas  

E-Print Network [OSTI]

-dimensional attractive Fermi gas Iacopo Carusotto 1, 2 and Yvan Castin 1, #3; 1 Laboratoire Kastler Brossel, #19; Ecole approaches. The crossover to a condensate of pairs can be identi#12;ed as the #12;rst-order pair coherence atomic samples at temperatures well below the degeneracy temperature [1]. This suggests that atomic gases

219

Study of nuclear giant resonances using a Fermi-liquid method  

E-Print Network [OSTI]

The nuclear giant resonances are studied by using a Fermi-liquid method, and the nuclear collective excitation energies of different values of $l$ are obtained, which are fitted with the centroid energies of the giant resonances of spherical nuclei, respectively. In addition, the relation between the isovector giant resonance and the corresponding isoscalar giant resonance is discussed.

Bao-Xi Sun

2012-01-27T23:59:59.000Z

220

Solitary waves in Galilean covariant Fermi field theories with self-interaction  

E-Print Network [OSTI]

The generalized Levy-Leblond equation for a $(3+1)$-dimensional self-interacting Fermi field is considered. Spin up solitary wave solutions with space oscillations in the $x^3$-coordinate are constructed. The solutions are shown to accumulate non-equal amounts of inertial and rest masses.

Saradzhev, Fuad M

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "fermi reveals entire" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

Fermi National Accelerator Laboratory FERMILAB-Pub-99/354-E  

E-Print Network [OSTI]

Fermi National Accelerator Laboratory FERMILAB-Pub-99/354-E D0 The Isolated Photon Cross Section Purposes. #12;Fermilab-Pub-99 354-E The Isolated Photon Cross Section in pp Collisions at ps = 1.8 TeV B

222

Extending the Fermi-LAT Data Processing Pipeline to the Grid  

E-Print Network [OSTI]

The Data Handling Pipeline ("Pipeline") has been developed for the Fermi Gamma-Ray Space Telescope (Fermi) Large Area Telescope (LAT) which launched in June 2008. Since then it has been in use to completely automate the production of data quality monitoring quantities, reconstruction and routine analysis of all data received from the satellite and to deliver science products to the collaboration and the Fermi Science Support Center. Aside from the reconstruction of raw data from the satellite (Level 1), data reprocessing and various event-level analyses are also reasonably heavy loads on the pipeline and computing resources. These other loads, unlike Level 1, can run continuously for weeks or months at a time. In addition it receives heavy use in performing production Monte Carlo tasks. The software comprises web-services that allow online monitoring and provides charts summarizing work flow aspects and performance information. The server supports communication with several batch systems such as LSF and BQS and recently also Sun Grid Engine and Condor. This is accomplished through dedicated job control services that for Fermi are running at SLAC and the other computing site involved in this large scale framework, the Lyon computing center of IN2P3. While being different in the logic of a task, we evaluate a separate interface to the Dirac system in order to communicate with EGI sites to utilize Grid resources, using dedicated Grid optimized systems rather than developing our own. (abstract abridged)

Stephan Zimmer; Luisa Arrabito; Tom Glanzman; Tony Johnson; Claudia Lavalley; Andrei Tsaregorodtsev

2012-12-17T23:59:59.000Z

223

Mean-field analysis of the stability of a K-Rb Fermi-Bose mixture  

Science Journals Connector (OSTI)

We compare the experimental stability diagram of a Fermi-Bose mixture of 40K and 87Rb atoms with attractive interaction to the predictions of a mean-field theoretical model. We discuss how this comparison can be used to give a better estimate of the interspecies scattering length, which is currently known from collisional measurements with larger uncertainty.

M. Modugno; F. Ferlaino; F. Riboli; G. Roati; G. Modugno; M. Inguscio

2003-10-29T23:59:59.000Z

224

Large Fermi energy modulation in graphene transistors with high-pressure O{sub 2}-annealed Y{sub 2}O{sub 3} topgate insulators  

SciTech Connect (OSTI)

We demonstrate a considerable suppression of the low-field leakage through a Y{sub 2}O{sub 3} topgate insulator on graphene by applying high-pressure O{sub 2} at 100?atm during post-deposition annealing (HP-PDA). Consequently, the quantum capacitance measurement for the monolayer graphene reveals the largest Fermi energy modulation (E{sub F}?=??0.52?eV, i.e., the carrier density of ?2?×?10{sup 13}?cm{sup ?2}) in the solid-state topgate insulators reported so far. HP-PDA is the robust method to improve the electrical quality of high-k insulators on graphene.

Kanayama, Kaoru; Nagashio, Kosuke, E-mail: nagashio@material.t.u-tokyo.ac.jp; Nishimura, Tomonori; Toriumi, Akira [Department of Materials Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan)

2014-02-24T23:59:59.000Z

225

Christmas burst reveals neutron star collision  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Christmas burst reveals neutron star collision Christmas burst reveals neutron star collision Called the Christmas Burst, GRB 101225A was freakishly lengthy and it produced...

226

The Entire General Science Archive  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

General Topics Archives General Topics Archives General Topics Archives, Since November 1991 Table of Contents: What Sciences are included in Earth Science? Magnetosphere Magnetic Compasses Aftershocks vs. Earthquakes Illinois Earthquakes Center of the Earth Why is the Earth round? Project Mohole Minerals, Rocks, or not? Water Origin of Saltwater Weight of Clouds Barometers Chaos and Weather Forecasting Lightning Strikes Tornado Spinning Tornado Safety in a Building Tornadoes and High Rise Structures Tornadoes Avoiding Downtown Chicago Coldest Temperature? Thermal Inversions Fog Blue Sky Gravitational pull vs. Atmospheric pressure Weights and Measures Science Demonstrations Cyanide Gas Bermuda Triangle X-30 Flower colors Ice Cream Headaches Rubber Egg Silver Dental Fillings and Aluminum Foil Birds and Wires

227

The Entire Molecular Biology Archive  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Molecular Biology Archives Molecular Biology Archives Molecular Biology, Since May 2000 Table of Contents: Blood pH and Oxygen DNA Extraction Flesh Eating Bacteria Amino Acid Differences Lyme Disease Effects Vinegar and Alcohol Mosquito and Blood Caffeine and Smoking Bread Mold and pH Hemocyanin and Hemerythrin Hodospin Man-made Bacteria Pregnancy Tips mRNA Killing Bacteria Gram Stain Milk Bacteria Denatured Protein Pseudmands Bacteria Nucleotide Order Bacteria Resistance Albinism Genes DNA Healing Re-constitution of Proteins H. pylori and Multiple sclerosis Smallest Organism Sugars and Fats Bacteria Systematics Slow Regeneration Media Cultures Butter and Bacteria AIDS and Survival in Air Cell Intelligence Giardia gingivalis Meat Bacteria Pus and Immune Cells Chalones Culture of T. ferrooxisans Amphibian E. coli

228

Towards understanding the entire universe  

Science Journals Connector (OSTI)

......laboratory magnetohydrodynamics (MHD) in controlled thermonuclear fusion. The overall aim was to produce a plasma hot enough...supernova stages of massive star evo- lution, and to thermonuclear explosions of white dwarf material in supernovae......

Leon Mestel

1999-12-01T23:59:59.000Z

229

Electron momentum density and the Fermi surface of ?-PdH0.84 by Compton scattering  

Science Journals Connector (OSTI)

The geometry of the Fermi surface of ?-PdH0.84 has been determined by the synchrotron-based Compton scattering experiment with 115keV x rays. The Fermi surface is mapped out from the electron momentum density which is three-dimensionally reconstructed from 12 directional Compton profiles. It is found that the Fermi surface is a deformed electron sphere with a neck along the [111] direction like a noble metal. The Fermi momenta are 0.63±0.02atomicunits in the [100] direction and 0.65±0.16atomicunits in the [110] direction, and the neck radius is 0.18±0.03atomicunits around the [111] direction. This result agrees satisfactorily with that of first-principles band structure calculations within the effective experimental momentum resolution.

S. Mizusaki; T. Miyatake; N. Sato; I. Yamamoto; M. Yamaguchi; M. Itou; Y. Sakurai

2006-03-06T23:59:59.000Z

230

Ground Broken for New Job-Creating Accelerator Research Facility at DOE’s Fermi National Accelerator Laboratory in Illinois  

Broader source: Energy.gov [DOE]

WASHINGTON, D.C. – Today, ground was broken for a new accelerator research facility being built at the Department of Energy’s (DOE’s) Fermi National Accelerator Laboratory (Fermilab) in Batavia,...

231

Polaron-molecule transitions in a two-dimensional Fermi gas  

SciTech Connect (OSTI)

We address the problem of a single 'spin-down' impurity atom interacting attractively with a spin-up Fermi gas in two dimensions (2D). We consider the case where the mass of the impurity is greater than or equal to the mass of a spin-up fermion. Using a variational approach, we resolve the questions raised by previous studies and show that there is, in fact, a transition between polaron and molecule (dimer) ground states in 2D. For the molecule state, we use a variational wave function with a single particle-hole excitation on the Fermi sea and we find that its energy matches that of the exact solution in the limit of infinite impurity mass. Thus, we expect the variational approach to provide a reliable tool for investigating 2D systems.

Parish, Meera M. [Cavendish Laboratory, JJ Thomson Avenue, Cambridge, CB3 0HE (United Kingdom)

2011-05-15T23:59:59.000Z

232

Phenomenological theory of non-Fermi-liquid heavy-fermion alloys  

Science Journals Connector (OSTI)

We propose a phenomenological theory for heavy-fermion metallic allows U0.2Y0.8Pd3 and UCu3.5Pd1.5 whose behavior demonstrates strong deviations from the Landau Fermi-liquid theory. The theory implies that the alloys have a critical point at T=0 and therefore their low-temperature thermodynamics is determined not by single-particle fermion excitations, as in the Fermi liquid, but by the collective modes corresponding to fluctuations of the order parameter in the vicinity of the critical point. The observed properties are consistent with the fluctuation spectrum ??q3. Both quantum spin-glass transition and quadrupolar ordering are ruled out by the scaling analysis.

A. M. Tsvelik and M. Reizer

1993-10-01T23:59:59.000Z

233

Optical properties of quantum wires: Fermi-edge singularity exponents and the low-density limit  

Science Journals Connector (OSTI)

A simple many-body treatment of the Fermi-edge singularities in absorption and photoemission in quasi-one-dimensional quantum wires is presented. The problem of calculating the transition probabilities is reduced to numerically evaluating a sufficient number of determinants describing the overlap of the appropriate many-body wave functions. It is found that the edge singularity exponents can be determined from the size dependence of these determinants. The well-known connection between these exponents and the phase shifts at the Fermi surface are explicitly checked for one-dimensional quantum wires. The singular edge behavior is interpreted in terms of Friedel’s replacement transitions and is found to be due to a replacement transition to the bound state, a result confirmed by considering the evolution of the spectra in the low-density limit. © 1996 The American Physical Society.

H. H. von Grünberg; K. P. Jain; R. J. Elliott

1996-07-15T23:59:59.000Z

234

Phase separation and collapse in Bose-Fermi mixtures with a Feshbach resonance  

Science Journals Connector (OSTI)

We consider a mixture of single-component bosonic and fermionic atoms with an interspecies interaction that is varied using a Feshbach resonance. By performing a mean-field analysis of a two-channel model, which describes both narrow and broad Feshbach resonances, we find an unexpectedly rich phase diagram at zero temperature: Bose-condensed and non-Bose-condensed phases form a variety of phase-separated states that are accompanied by both critical and tricritical points. We discuss the implications of our results for the experimentally observed collapse of Bose-Fermi mixtures on the attractive side of the Feshbach resonance, and we make predictions for future experiments on Bose-Fermi mixtures close to a Feshbach resonance.

Francesca M. Marchetti; Charles J. M. Mathy; David A. Huse; Meera M. Parish

2008-10-14T23:59:59.000Z

235

Transverse Collective Flow and Emission Order of Mid-Rapidity Fragments in Fermi Energy Heavy Ion Collisions  

E-Print Network [OSTI]

TRANSVERSE COLLECTIVE FLOW AND EMISSION ORDER OF MID-RAPIDITY FRAGMENTS IN FERMI ENERGY HEAVY ION COLLISIONS A Dissertation by ZACHARY WAYNE KOHLEY Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment... of the requirements for the degree of DOCTOR OF PHILOSOPHY August 2010 Major Subject: Chemistry TRANSVERSE COLLECTIVE FLOW AND EMISSION ORDER OF MID-RAPIDITY FRAGMENTS IN FERMI ENERGY HEAVY ION COLLISIONS A Dissertation by ZACHARY WAYNE KOHLEY Submitted...

Kohley, Zachary Wayne

2011-10-21T23:59:59.000Z

236

Hybrid Monte Carlo with Wilson Dirac operator on the Fermi GPU  

E-Print Network [OSTI]

In this article we present our implementation of a Hybrid Monte Carlo algorithm for Lattice Gauge Theory using two degenerate flavours of Wilson-Dirac fermions on a Fermi GPU. We find that using registers instead of global memory speeds up the code by almost an order of magnitude. To map the array variables to scalars, so that the compiler puts them in the registers, we use code generators. Our final program is more than 10 times faster than a generic single CPU.

Abhijit Chakrabarty; Pushan Majumdar

2012-07-10T23:59:59.000Z

237

Accurate calculation of the solutions to the Thomas-Fermi equations  

E-Print Network [OSTI]

We obtain highly accurate solutions to the Thomas-Fermi equations for atoms and atoms in very strong magnetic fields. We apply the Pad\\'e-Hankel method, numerical integration, power series with Pad\\'e and Hermite-Pad\\'e approximants and Chebyshev polynomials. Both the slope at origin and the location of the right boundary in the magnetic-field case are given with unprecedented accuracy.

Paolo Amore; John P. Boyd; Francisco M. Fernández

2012-05-08T23:59:59.000Z

238

Swift and Fermi observations of X-ray flares: the case of Late Internal Shock  

E-Print Network [OSTI]

Simultaneous Swift and Fermi observations of gamma-ray bursts (GRBs) offer a unique broadband view of their afterglow emission, spanning more than ten decades in energy. We present the sample of X-ray flares observed by both Swift and Fermi during the first three years of Fermi operations. While bright in the X-ray band, X-ray flares are often undetected at lower (optical), and higher (MeV to GeV) energies. We show that this disfavors synchrotron self-Compton processes as origin of the observed X-ray emission. We compare the broadband properties of X-ray flares with the standard late internal shock model, and find that, in this scenario, X-ray flares can be produced by a late-time relativistic (Gamma>50) outflow at radii R~10^13-10^14 cm. This conclusion holds only if the variability timescale is significantly shorter than the observed flare duration, and implies that X-ray flares can directly probe the activity of the GRB central engine.

Troja, E; Vasileiou, V; Omodei, N; Burgess, J M; Cutini, S; Connaughton, V; McEnery, J E

2014-01-01T23:59:59.000Z

239

In-medium effects for nuclear matter in the Fermi energy domain  

E-Print Network [OSTI]

We study nuclear stopping in central collisions for heavy-ion induced reactions in the Fermi energy domain, between $15$ and $100$ A\\,\\textrm{MeV}. Using the large dataset of exclusive measurements provided by the $4\\pi$ array \\emph{INDRA}, we determine the relative degree of stopping as a function of system mass and bombarding energy. We show that the stopping can be directly related to the transport properties in the nuclear medium. By looking specifically at free nucleons (here protons), we present for the first time a comprehensive body of experimental results concerning the mean free path, the nucleon-nucleon cross-section and in-medium effects in nuclear matter. It is shown that the mean free path exhibits a maximum at $\\lambda_{NN}=9.5 \\pm 2$ \\textrm{fm}, around $E_{inc}=35-40$ A\\,\\textrm{MeV} incident energy and decreases toward an asymptotic value $\\lambda_{NN}= 4.5 \\pm 1$ \\textrm{fm} at $E_{inc} = 100$ A\\,\\textrm{MeV}. After accounting for Pauli blocking of elastic nucleon-nucleon collisions, it is shown that the effective in-medium \\emph{NN} cross section is further reduced compared to the free value in this energy range. Therefore, in-medium effects cannot be neglected in the Fermi energy range. These results bring new fundamental inputs for microscopic descriptions of nuclear reactions in the Fermi energy domain.

O. Lopez; D. Durand; G. Lehaut; B. Borderie; M. F. Rivet; R. Bougault; E. Galichet; D. Guinet; N. Le Neindre; P. Marini; P. Napolitani; M. Pârlog; E. Rosato; G. Spadaccini; E. Vient; M. Vigilante

2014-09-02T23:59:59.000Z

240

Collective ferromagnetism in two-component Fermi-degenerate gas trapped in a finite potential  

Science Journals Connector (OSTI)

Spin asymmetry of ground states is studied in trapped spin-degenerate (two-component) gases of fermionic atoms with repulsive interaction between different components; and, for a large particle number, the asymmetric (collective ferromagnetic) states are shown to be stable because it can be energetically favorable to increase the Fermi energy of one component rather than increase the interaction energy between up-down components. We formulate the Thomas-Fermi equations and give algebraic methods to solve them. From the Thomas-Fermi solutions, we find three kinds of ground states in the finite system: (1) paramagnetic (spin-symmetric), (2) ferromagnetic (equilibrium), and (3) ferromagnetic (nonequilibrium) states. We present the density profiles and the critical atom numbers for these states obtained analytically, and, in ferromagnetic states, the spin asymmetries are shown to occur in the central region of the trapped gas, and increase with increasing particle number. Based on the obtained results, we discuss the experimental conditions and current difficulties in realizing the ferromagnetic states of the trapped atom gas, which should be overcome.

T. Sogo and H. Yabu

2002-10-21T23:59:59.000Z

Note: This page contains sample records for the topic "fermi reveals entire" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

Broad Line Radio Galaxies Observed with Fermi-LAT: The Origin of the GeV Gamma-Ray Emission  

SciTech Connect (OSTI)

We report on a detailed investigation of the {gamma}-ray emission from 18 broad line radio galaxies (BLRGs) based on two years of Fermi Large Area Telescope (LAT) data. We confirm the previously reported detections of 3C 120 and 3C 111 in the GeV photon energy range; a detailed look at the temporal characteristics of the observed {gamma}-ray emission reveals in addition possible flux variability in both sources. No statistically significant {gamma}-ray detection of the other BLRGs was however found in the considered dataset. Though the sample size studied is small, what appears to differentiate 3C 111 and 3C 120 from the BLRGs not yet detected in {gamma}-rays is the particularly strong nuclear radio flux. This finding, together with the indications of the {gamma}-ray flux variability and a number of other arguments presented, indicate that the GeV emission of BLRGs is most likely dominated by the beamed radiation of relativistic jets observed at intermediate viewing angles. In this paper we also analyzed a comparison sample of high accretion-rate Seyfert 1 galaxies, which can be considered radio-quiet counterparts of BLRGs, and found none were detected in {gamma}-rays. A simple phenomenological hybrid model applied for the broad-band emission of the discussed radio-loud and radio-quiet type 1 active galaxies suggests that the relative contribution of the nuclear jets to the accreting matter is {ge} 1% on average for BLRGs, while {le} 0.1% for Seyfert 1 galaxies.

Kataoka, J.; /Waseda U., RISE; Stawarz, L.; /JAXA, Sagamihara /Jagiellonian U., Astron. Observ.; Takahashi, Y.; /Waseda U., RISE; Cheung, C.C.; /Natl. Acad. Sci. /Naval Research Lab, Wash., D.C.; Hayashida, M.; /SLAC /Stanford U., HEPL /KIPAC, Menlo Park; Grandi, P.; /Bologna Observ.; Burnett, T.H.; /Washington U., Seattle; Celotti, A.; /SISSA, Trieste; Fegan, S.J.; Fortin, P.; /Ecole Polytechnique; Maeda, K.; Nakamori, T.; /Waseda U., RISE; Taylor, G.B.; /New Mexico U.; Tosti, G.; /INFN, Perugia /Perugia U.; Digel, S.W.; /SLAC /Stanford U., HEPL /KIPAC, Menlo Park; McConville, W.; /NASA, Goddard /Maryland U.; Finke, J.; /Naval Research Lab, Wash., D.C.; D'Ammando, F.; /IASF, Palermo /INAF, Rome

2012-06-07T23:59:59.000Z

242

Fermi LAT detection of two high Galactic latitude gamma-ray sources, Fermi J1049.7+0435 and J1103.2+1145  

E-Print Network [OSTI]

The Second Fermi LAT source catalog (Nolan et al. 2012) includes as many as 1,873 sources, but initial attempts to identify counterparts at other wavelengths resulted in 575 sources remaining unidentified. The 2FGL catalog is based on the first 24 months of LAT observation since its launch in 2008, but the LAT has now accumulated more than 5 years of high-energy gamma-ray data almost flawlessly, presenting the possibility of finding new sources which were too faint to be detected in the first two years of data or showed flaring activity after the catalog was created. In this paper we report on two new gamma-ray sources serendipitously discovered in the constellation Leo and discuss possible counterparts based on radio observations.

Nishimichi, Masaki; Mori, Masaki; Edwards, Philip G; Stevens, Jamie

2014-01-01T23:59:59.000Z

243

ON THE FERMI LARGE AREA TELESCOPE SURPLUS OF DIFFUSE GALACTIC GAMMA-RAY EMISSION  

SciTech Connect (OSTI)

Recent observations of diffuse Galactic ?-ray emission (DGE) by the Fermi Large Area Telescope (Fermi-LAT) have shown significant deviations, above a few GeV to about 100 GeV, from DGE models that use the GALPROP code for the propagation of cosmic ray (CR) particles outside their sources in the Galaxy and their interaction with the target distributions of the interstellar gas and radiation fields. The surplus of radiation observed is most pronounced in the inner Galaxy, where the concentration of CR sources is strongest. The present study investigates this 'Fermi-LAT Galactic Plane Surplus' by estimating the ?-ray emission from the sources themselves, which is disregarded in the above DGE models. It is shown that the expected hard spectrum of CRs, still confined in their sources (source cosmic rays, SCRs), can indeed explain this surplus. The method is based on earlier studies regarding the so-called EGRET GeV excess, which by now is generally interpreted as an instrumental effect. The contribution from SCRs is also predicted to increasingly exceed the DGE models above 100 GeV, up to ?-ray energies of about 10 TeV, where the corresponding surplus exceeds the hadronic part of the DGE by about one order of magnitude. Above such energies, the emission surplus should decrease again with energy due to the finite lifetime of the assumed supernova remnant sources. Observations of the DGE in the inner Galaxy at 15 TeV with the ground-based Milagro ?-ray detector and, at TeV energies, with the ARGO-YBJ detector are interpreted to provide confirmation of a significant SCR contribution to the DGE.

Völk, H. J. [Max-Planck-Institut für Kernphysik, P.O. Box 103980, D-69029 Heidelberg (Germany); Berezhko, E. G., E-mail: Heinrich.Voelk@mpi-hd.mpg.de [Yu. G. Shafer Institute of Cosmophysical Research and Aeronomy, 31 Lenin Avenue, 677980 Yakutsk (Russian Federation)

2013-11-10T23:59:59.000Z

244

Shear viscosity and spin sum rules in strongly interacting Fermi gases  

E-Print Network [OSTI]

Fermi gases with short-range interactions are ubiquitous in ultracold atomic systems. In the absence of spin-flipping processes the number of atoms in each spin species is conserved separately, and we discuss the associated Ward identities. For contact interactions the spin conductivity spectral function sigma_s(omega) has universal power-law tails at high frequency. We derive the spin f-sum rule and show that it is not affected by these tails in dviscosity spectral function eta(omega) has universal tails; in contrast they modify the viscosity sum rule in a characteristic way.

Tilman Enss

2012-09-14T23:59:59.000Z

245

Nuclear symmetry energy from the Fermi-energy difference in nuclei  

E-Print Network [OSTI]

The neutron-proton Fermi-energy difference and the correlation to nucleon separation energies for some magic nuclei are investigated with the Skyrme energy density functionals and nuclear masses, with which the nuclear symmetry energy at sub-saturation densities is constrained from 54 Skyrme parameter sets. The extracted nuclear symmetry energy at sub-saturation density of 0.11 fm$^{-3}$ is 26.2 $\\pm$ 1.0 MeV with 1.5 $\\sigma$ uncertainty. By further combining the neutron-skin thickness of 208Pb, ten Skyrme forces with slope parameter of 28energy around saturation densities.

Ning Wang; Li Ou; Min Liu

2013-03-15T23:59:59.000Z

246

Superscaling in Nuclei: A Search for Scaling Function Beyond the Relativistic Fermi Gas Model  

E-Print Network [OSTI]

We construct a scaling function $f(\\psi^{\\prime})$ for inclusive electron scattering from nuclei within the Coherent Density Fluctuation Model (CDFM). The latter is a natural extension to finite nuclei of the Relativistic Fermi Gas (RFG) model within which the scaling variable $\\psi^{\\prime}$ was introduced by Donnelly and collaborators. The calculations show that the high-momentum components of the nucleon momentum distribution in the CDFM and their similarity for different nuclei lead to quantitative description of the superscaling in nuclei. The results are in good agreement with the experimental data for different transfer momenta showing superscaling for negative values of $\\psi^{\\prime}$, including those smaller than -1.

A. N. Antonov; M. K. Gaidarov; D. N. Kadrev; M. V. Ivanov; E. Moya de Guerra; J. M. Udias

2004-02-25T23:59:59.000Z

247

Superscaling and Neutral Current Quasielastic Neutrino-Nucleus Scattering beyond the Relativistic Fermi Gas Model  

E-Print Network [OSTI]

The superscaling analysis is extended to include quasielastic (QE) scattering via the weak neutral current of neutrinos and antineutrinos from nuclei. The scaling function obtained within the coherent density fluctuation model (used previously in calculations of QE inclusive electron and charge-changing (CC) neutrino scattering) is applied to neutral current neutrino and antineutrino scattering with energies of 1 GeV from $^{12}$C with a proton and neutron knockout (u-channel inclusive processes). The results are compared with those obtained using the scaling function from the relativistic Fermi gas model and the scaling function as determined from the superscaling analysis (SuSA) of QE electron scattering.

A. N. Antonov; M. V. Ivanov; M. B. Barbaro; J. A. Caballero; E. Moya de Guerra; M. K. Gaidarov

2007-06-01T23:59:59.000Z

248

Fermi-liquid interactions and the superfluid density in d-wave superconductors  

Science Journals Connector (OSTI)

We construct a phenomenological superfluid Fermi-liquid-theory for a two-dimensional d-wave superconductor on a square lattice, and study the effect of quasiparticle interactions on the superfluid density. Using simple models for the dispersion and the Landau interaction function, we illustrate the deviation of these results from those for the isotropic superfluid. This allows us to reconcile the value and doping dependence of the superfluid density slope at low temperature obtained from penetration depth measurements, with photoemission data on nodal quasiparticles.

Arun Paramekanti and Mohit Randeria

2002-12-20T23:59:59.000Z

249

Theory of hybrid state in a metal with a small Fermi surface and strong collective excitations  

Science Journals Connector (OSTI)

We develop a theory of a hybrid state, where quasiparticles coexist with strong collective modes, taking as a starting point a model of infinitely many one-dimensional Mott insulators weakly coupled by interchain tunneling. This state exists at an intermediate temperature range and undergoes an antiferromagnetic phase transition at temperatures much smaller than the Mott-Hubbard gap. The most peculiar feature of the hybrid state is that its Fermi surface volume is unrelated to the electron density. We present a self-consistent derivation of the low-energy effective action for our model.

F. H. L. Essler and A. M. Tsvelik

2005-05-26T23:59:59.000Z

250

Hall effect in the marginal Fermi liquid regime of high-Tc superconductors  

Science Journals Connector (OSTI)

The detailed derivation of a theory for transport in quasi-two-dimensional metals, with small-angle elastic scattering and angle-independent inelastic scattering is presented. The transport equation is solved for a model Fermi surface representing a typical cuprate superconductor. Using the small-angle elastic and the inelastic scattering rates deduced from angle-resolved photoemission experiments, good quantitative agreement with the observed anomalous temperature dependence of the Hall angle in optimally doped cuprates is obtained, while the resistivity remains linear in temperature. The theory is also extended to the frequency-dependent complex Hall angle.

Elihu Abrahams and C. M. Varma

2003-09-04T23:59:59.000Z

251

Fermi Observations  

Office of Scientific and Technical Information (OSTI)

Sander 40 , J. D. Scargle 57 , T. L. Schalk 3 , C. Sgr o 7 , E. J. Siskind 58 , P. D. Smith 40 , G. Spandre 7 , P. Spinelli 18,19 , M. Stamatikos 23,40 , F. W. Stecker 23 , M. S....

252

Elastic constants and Fermi surface topology change in Calaverite AuTe{sub 2}: A density functional study  

SciTech Connect (OSTI)

Structural, elastic, electronic and Fermi surface studies of AuTe{sub 2} have been carried out by means of first principles calculations based on density functional theory. The calculated ground state properties agree well with the experiment. Fermi surface and elastic constants are predicted for the first time and from the calculated elastic constants we find the compound to be mechanically stable satisfying the stability criteria of monoclinic structure. In addition, we also find the c-axis to be more compressible than the other two which is also speculated from the present work. The metallic behaviour of this compound is confirmed from the electronic band structure calculation as we find the bands to cross the Fermi level (E{sub F}). In addition, we also observe a FS topology change under pressure which is also explained in the present work.

Gudelli, Vijay Kumar, E-mail: kanchana@iith.ac.in; Kanchana, V., E-mail: kanchana@iith.ac.in [Department of Physics, Indian Institute of Technology Hyderabad, Ordnance Factory Estate, Yeddumailaram-502205, Andhra Pradesh (India)

2014-04-24T23:59:59.000Z

253

Bounds on Spectral Dispersion from Fermi-Detected Gamma Ray Bursts  

Science Journals Connector (OSTI)

Data from four Fermi-detected gamma-ray bursts (GRBs) are used to set limits on spectral dispersion of electromagnetic radiation across the Universe. The analysis focuses on photons recorded above 1 GeV for Fermi-detected GRB 080916C, GRB 090510A, GRB 090902B, and GRB 090926A because these high-energy photons yield the tightest bounds on light dispersion. It is shown that significant photon bunches in GRB 090510A, possibly classic GRB pulses, are remarkably brief, an order of magnitude shorter in duration than any previously claimed temporal feature in this energy range. Although conceivably a>3? fluctuation, when taken at face value, these pulses lead to an order of magnitude tightening of prior limits on photon dispersion. Bound of ?c/c<6.94×10-21 is thus obtained. Given generic dispersion relations where the time delay is proportional to the photon energy to the first or second power, the most stringent limits on the dispersion strengths were k1<1.61×10-5??sec?Gpc-1?GeV-1 and k2<3.57×10-7??sec?Gpc-1?GeV-2, respectively. Such limits constrain dispersive effects created, for example, by the spacetime foam of quantum gravity. In the context of quantum gravity, our bounds set M1c2 greater than 525 times the Planck mass, suggesting that spacetime is smooth at energies near and slightly above the Planck mass.

Robert J. Nemiroff; Ryan Connolly; Justin Holmes; Alexander B. Kostinski

2012-06-08T23:59:59.000Z

254

The Fermi blazars' divide based on the diagnostic of the SEDs peak frequencies  

E-Print Network [OSTI]

We have studied the quasi-simultaneous Spectral Energy Distributions (SED) of 48 LBAS blazars, detected within the three months of the LAT Bright AGN Sample (LBAS) data taking period, combining Fermi and Swift data with radio NIR-Optical and hard-X/gamma-ray data. Using these quasi-simultaneous SEDs, sampling both the low and the high energy peak of the blazars broad band emission, we were able to apply a diagnostic tool based on the estimate of the peak frequencies of the synchrotron (S) and Inverse Compton (IC) components. Our analysis shows a Fermi blazars' divide based on the peak frequencies of the SED. The robust result is that the Synchrotron Self Compton (SSC) region divides in two the plane were we plot the peak frequency of the synchrotron SED vs the typical Lorentz factor of the electrons most contributing to the synchrotron emission and to the inverse Compton process. Objects within or below this region, radiating likely via the SSC process, are high-frequency-peaked BL Lac object (HBL), or low/in...

Tramacere, A; Giommi, P; Mazziotta, N; Monte, C

2010-01-01T23:59:59.000Z

255

THE SECOND FERMI LARGE AREA TELESCOPE CATALOG OF GAMMA-RAY PULSARS  

SciTech Connect (OSTI)

This catalog summarizes 117 high-confidence ?0.1 GeV gamma-ray pulsar detections using three years of data acquired by the Large Area Telescope (LAT) on the Fermi satellite. Half are neutron stars discovered using LAT data through periodicity searches in gamma-ray and radio data around LAT unassociated source positions. The 117 pulsars are evenly divided into three groups: millisecond pulsars, young radio-loud pulsars, and young radio-quiet pulsars. We characterize the pulse profiles and energy spectra and derive luminosities when distance information exists. Spectral analysis of the off-peak phase intervals indicates probable pulsar wind nebula emission for four pulsars, and off-peak magnetospheric emission for several young and millisecond pulsars. We compare the gamma-ray properties with those in the radio, optical, and X-ray bands. We provide flux limits for pulsars with no observed gamma-ray emission, highlighting a small number of gamma-faint, radio-loud pulsars. The large, varied gamma-ray pulsar sample constrains emission models. Fermi's selection biases complement those of radio surveys, enhancing comparisons with predicted population distributions.

Abdo, A. A. [Center for Earth Observing and Space Research, College of Science, George Mason University, Fairfax, VA 22030 (United States); Ajello, M. [Space Sciences Laboratory, 7 Gauss Way, University of California, Berkeley, CA 94720-7450 (United States); Allafort, A.; Bloom, E. D.; Bottacini, E. [W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States); Baldini, L. [Università di Pisa and Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, I-56127 Pisa (Italy); Ballet, J. [Laboratoire AIM, CEA-IRFU/CNRS/Université Paris Diderot, Service d'Astrophysique, CEA Saclay, F-91191 Gif sur Yvette (France); Barbiellini, G. [Istituto Nazionale di Fisica Nucleare, Sezione di Trieste, I-34127 Trieste (Italy); Baring, M. G. [Rice University, Department of Physics and Astronomy, MS-108, P.O. Box 1892, Houston, TX 77251 (United States); Bastieri, D. [Istituto Nazionale di Fisica Nucleare, Sezione di Padova, I-35131 Padova (Italy); Belfiore, A. [Santa Cruz Institute for Particle Physics, Department of Physics and Department of Astronomy and Astrophysics, University of California at Santa Cruz, Santa Cruz, CA 95064 (United States); Bellazzini, R.; Bregeon, J. [Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, I-56127 Pisa (Italy); Bhattacharyya, B. [National Centre for Radio Astrophysics, Tata Institute of Fundamental Research, Pune 411 007 (India); Bissaldi, E. [Istituto Nazionale di Fisica Nucleare, Sezione di Trieste, and Università di Trieste, I-34127 Trieste (Italy); Bonamente, E. [Istituto Nazionale di Fisica Nucleare, Sezione di Perugia, I-06123 Perugia (Italy); Brandt, T. J. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Brigida, M., E-mail: hartog@stanford.edu [Dipartimento di Fisica ''M. Merlin'' dell'Università e del Politecnico di Bari, I-70126 Bari (Italy); and others

2013-10-01T23:59:59.000Z

256

Localization of Gamma-Ray Bursts using the Fermi Gamma-Ray Burst Monitor  

E-Print Network [OSTI]

The Fermi Gamma-ray Burst Monitor (GBM) has detected over 1400 Gamma-Ray Bursts (GRBs) since it began science operations in July, 2008. We use a subset of over 300 GRBs localized by instruments such as Swift, the Fermi Large Area Telescope, INTEGRAL, and MAXI, or through triangulations from the InterPlanetary Network (IPN), to analyze the accuracy of GBM GRB localizations. We find that the reported statistical uncertainties on GBM localizations, which can be as small as 1 degree, underestimate the distance of the GBM positions to the true GRB locations and we attribute this to systematic uncertainties. The distribution of systematic uncertainties is well represented (68% confidence level) by a 3.7 degree Gaussian with a non-Gaussian tail that contains about 10% of GBM-detected GRBs and extends to approximately 14 degrees. A more complex model suggests that there is a dependence of the systematic uncertainty on the position of the GRB in spacecraft coordinates, with GRBs in the quadrants on the Y-axis better l...

Connaughton, V; Goldstein, A; Meegan, C A; Paciesas, W S; Preece, R D; Wilson-Hodge, C A; Gibby, M H; Greiner, J; Gruber, D; Jenke, P; Kippen, R M; Pelassa, V; Xiong, S; Yu, H -F; Bhat, P N; Burgess, J M; Byrne, D; Fitzpatrick, G; Foley, S; Giles, M M; Guiriec, S; van der Horst, A J; von Kienlin, A; McBreen, S; McGlynn, S; Tierney, D; Zhang, B -B

2014-01-01T23:59:59.000Z

257

Dark matter and pulsar model constraints from Galactic Center Fermi-LAT gamma-ray observations  

Science Journals Connector (OSTI)

Employing Fermi-LAT gamma-ray observations, several independent groups have found excess extended gamma-ray emission at the Galactic Center (GC). Both annihilating dark matter (DM) or a population of ?103 unresolved millisecond pulsars (MSPs) are regarded as well-motivated possible explanations. However, there are significant uncertainties in the diffuse galactic background at the GC. We have performed a revaluation of these two models for the extended gamma-ray source at the GC by accounting for the systematic uncertainties of the Galactic diffuse emission model. We also marginalize over point-source and diffuse background parameters in the region of interest. We show that the excess emission is significantly more extended than a point source. We find that the DM (or pulsar-population) signal is larger than the systematic errors and therefore proceed to determine the sectors of parameter space that provide an acceptable fit to the data. We find that a population of 1000–2000 MSPs with parameters consistent with the average spectral shape of Fermi-LAT measured MSPs is able to fit the GC excess emission. For DM, we find that a pure ?+?- annihilation channel is not a good fit to the data. But a mixture of ?+?- and bb¯ with a ??v? of order the thermal relic value and a DM mass of around 20 to 60 GeV provides an adequate fit.

Chris Gordon and Oscar Macías

2013-10-21T23:59:59.000Z

258

The Third Catalog of Active Galactic Nuclei Detected by the Fermi Large Area Telescope  

E-Print Network [OSTI]

The third catalog of active galactic nuclei (AGNs) detected by the Fermi-LAT (3LAC) is presented. It is based on the third Fermi-LAT catalog (3FGL) of sources detected with a test statistic (TS) greater than 25, using the first 4 years of data. The 3LAC includes 1591 AGNs located at high Galactic latitudes (|b|>10{\\deg}), which is a 71% increase over the second catalog that was based on 2 years of data. There are 28 duplicate associations (two counterparts to the same gamma-ray source), thus 1563 of the 2192 high-latitude gamma-ray sources of the 3FGL catalog are AGNs. A very large majority of these AGNs (98%) are blazars. About half of the newly detected blazars are of unknown type, i.e., they lack spectroscopic information of sufficient quality to determine the strength of their emission lines. Based on their spectral properties, these sources are evenly split between FSRQs and BL~Lacs. The general properties of the 3LAC sample confirm previous findings from earlier catalogs, but some new subclasses (e.g., ...

Ackermann, M; Atwood, W; Baldini, L; Ballet, J; Barbiellini, G; Bastieri, D; Gonzalez, J; Bellazzini, R; Bissaldi, E; Blandford, R; Bloom, E; Bonino, R; Bottacini, E; Brandt, T; Bregeon, J; Britto, R; Bruel, P; Buehler, R; Buson, S; Caliandro, G; Cameron, R; Caragiulo, M; Caraveo, P; Casandjian, J; Cavazzuti, E; Cecchi, C; Charles, E; Chekhtman, A; Cheung, C; Chiang, J; Chiaro, G; Ciprini, S; Claus, R; Cohen-Tanugi, J; Cominsky, L; Conrad, J; Cutini, S; D'Abrusco, R; D'Ammando, F; Angelis, A; Desiante, R; Digel, S; Venere, L; Drell, P; Favuzzi, C; Fegan, S; Ferrara, E; Finke, J; Focke, W; Franckowiak, A; Fuhrmann, L; Furniss, A; Fusco, P; Gargano, F; Gasparrini, D; Giglietto, N; Giommi, P; Giordano, F; Giroletti, M; Glanzman, T; Godfrey, G; Grenier, I; Grove, J; Guiriec, S; Hewitt, J W; Hill, A; Horan, D; J'ohannesson, G; Johnson, A; Johnson, W; Kataoka, J; Kuss, M; Mura, G; Larsson, S; Latronico, L; Leto, C; Li, J; Li, L; Longo, F; Loparco, F; Lott, B; Lovellette, M; Lubrano, P; Madejski, G; Mayer, M; Mazziotta, M; McEnery, J; Michelson, P; Mizuno, T; Moiseev, A; Monzani, M; Morselli, A; Moskalenko, I; Murgia, S; Nuss, E; Ohno, M; Ohsugi, T; Ojha, R; Omodei, N; Orienti, M; Orlando, E; Paggi, A; Paneque, D; Perkins, J; Pesce-Rollins, M; Piron, F; Pivato, G; Porter, T; Rain`o, S; Rando, R; Razzano, M; Razzaque, S; Reimer, A; Reimer, O; Romani, R; Salvetti, D; Schaal, M; Schinzel, F; Schulz, A; Sgr`o, C; Siskind, E; Sokolovsky, K; Spada, F; Spandre, G; Spinelli, P; Stawarz, L; Suson, D; Takahashi, H; Takahashi, T; Tanaka, Y; Thayer, J; Thayer, J; Tibaldo, L; Torres, D; Torresi, E; Tosti, G; Troja, E; Uchiyama, Y; Vianello, G; Winer, B; Wood, K; Zimmer, S

2015-01-01T23:59:59.000Z

259

Multi-wavelength Emission from the Fermi Bubble I. Stochastic acceleration from Background Plasma  

E-Print Network [OSTI]

We analyse processes of electron acceleration in the Fermi Bubbles in order to define parameters and restrictions of the models, which are suggested for the origin of these giant radio and gamma-ray structures. In the case of leptonic origin of the nonthermal radiation from the Bubbles, these electrons should be produced somehow in-situ because of relatively short lifetime of high energy electrons, which lose their energy by synchrotron and inverse Compton processes. It has been suggested that electrons in Bubbles may be accelerated by shocks produced by tidal disruption of star accreting onto the central black hole or a process of re-acceleration of electrons ejected by supernova remnants. These processes will be investigated in subsequent papers. In this paper we focus to study in-situ stochastic (Fermi) acceleration by a hydromagnetic/supersonic turbulence, in which electrons can be directly accelerated from the background plasma. We showed that the acceleration from the background plasma is able to explai...

Cheng, K S; Dogiel, V A; Ko, C M

2014-01-01T23:59:59.000Z

260

ccsd-00000540(version1):1Aug2003 Production of Long-Lived Ultracold Li2 Molecules from a Fermi gas  

E-Print Network [OSTI]

samples, the collapse of Bose-Einstein condensates (BEC) for negative scattering length [4], solitonccsd-00000540(version1):1Aug2003 Production of Long-Lived Ultracold Li2 Molecules from a Fermi gas a degenerate two component Fermi gas by sweeping a magnetic field across a Feshbach resonance. The atom

Paris-Sud XI, Université de

Note: This page contains sample records for the topic "fermi reveals entire" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

The Large Area Telescope on the Fermi Gamma-ray Space Telescope Mission  

SciTech Connect (OSTI)

The Large Area Telescope (Fermi/LAT, hereafter LAT), the primary instrument on the Fermi Gamma-ray Space Telescope (Fermi) mission, is an imaging, wide field-of-view (FoV), high-energy {gamma}-ray telescope, covering the energy range from below 20 MeV to more than 300 GeV. The LAT was built by an international collaboration with contributions from space agencies, high-energy particle physics institutes, and universities in France, Italy, Japan, Sweden, and the United States. This paper describes the LAT, its preflight expected performance, and summarizes the key science objectives that will be addressed. On-orbit performance will be presented in detail in a subsequent paper. The LAT is a pair-conversion telescope with a precision tracker and calorimeter, each consisting of a 4 x 4 array of 16 modules, a segmented anticoincidence detector that covers the tracker array, and a programmable trigger and data acquisition system. Each tracker module has a vertical stack of 18 (x, y) tracking planes, including two layers (x and y) of single-sided silicon strip detectors and high-Z converter material (tungsten) per tray. Every calorimeter module has 96 CsI(Tl) crystals, arranged in an eight-layer hodoscopic configuration with a total depth of 8.6 radiation lengths, giving both longitudinal and transverse information about the energy deposition pattern. The calorimeter's depth and segmentation enable the high-energy reach of the LAT and contribute significantly to background rejection. The aspect ratio of the tracker (height/width) is 0.4, allowing a large FoV (2.4 sr) and ensuring that most pair-conversion showers initiated in the tracker will pass into the calorimeter for energy measurement. Data obtained with the LAT are intended to (1) permit rapid notification of high-energy {gamma}-ray bursts and transients and facilitate monitoring of variable sources, (2) yield an extensive catalog of several thousand high-energy sources obtained from an all-sky survey, (3) measure spectra from 20 MeV to more than 50 GeV for several hundred sources, (4) localize point sources to 0.3-2 arcmin, (5) map and obtain spectra of extended sources such as SNRs, molecular clouds, and nearby galaxies, (6) measure the diffuse isotropic {gamma}-ray background up to TeV energies, and (7) explore the discovery space for dark matter.

Atwood, W.B.; /UC, Santa Cruz; Abdo, Aous A.; /Naval Research Lab, Wash., D.C.; Ackermann, M.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Anderson, B. /UC, Santa Cruz; Axelsson, M.; /Stockholm U.; Baldini, L.; /INFN, Pisa; Ballet, J.; /DAPNIA, Saclay; Band, D.L.; /NASA, Goddard /NASA, Goddard; Barbiellini, Guido; /INFN, Trieste /Trieste U.; Bartelt, J.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bastieri, Denis; /INFN, Padua /Padua U.; Baughman, B.M.; /Ohio State U.; Bechtol, K.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bederede, D.; /DAPNIA, Saclay; Bellardi, F.; /INFN, Pisa; Bellazzini, R.; /INFN, Pisa; Berenji, B.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bignami, G.F.; /Pavia U.; Bisello, D.; /INFN, Padua /Padua U.; Bissaldi, E.; /Garching, Max Planck Inst., MPE; Blandford, R.D.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /INFN, Perugia /Perugia U. /NASA, Goddard /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /INFN, Pisa /INFN, Pisa /Bari U. /INFN, Bari /Ecole Polytechnique /Washington U., Seattle /INFN, Padua /Padua U. /Bari U. /INFN, Bari /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /IASF, Milan /IASF, Milan /Kalmar U. /Royal Inst. Tech., Stockholm /DAPNIA, Saclay /ASI, Rome /INFN, Pisa /INFN, Perugia /Perugia U. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /George Mason U. /Naval Research Lab, Wash., D.C. /NASA, Goddard /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /DAPNIA, Saclay /NASA, Goddard /INFN, Perugia /Perugia U. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Montpellier U. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; /more authors.; ,

2009-05-15T23:59:59.000Z

262

Observations of MilkyWay Dwarf Spheroidal galaxies with the Fermi-LAT detector and  

SciTech Connect (OSTI)

We report on the observations of 14 dwarf spheroidal galaxies with the Fermi Gamma-Ray Space Telescope taken during the first 11 months of survey mode operations. The Fermi telescope, which is conducting an all-sky {gamma}-ray survey in the 20 MeV to >300 GeV energy range, provides a new opportunity to test particle dark matter models through the expected {gamma}-ray emission produced by pair annihilation of weakly interacting massive particles (WIMPs). Local Group dwarf spheroidal galaxies, the largest galactic substructures predicted by the cold dark matter scenario, are attractive targets for such indirect searches for dark matter because they are nearby and among the most extreme dark matter dominated environments. No significant {gamma}-ray emission was detected above 100 MeV from the candidate dwarf galaxies. We determine upper limits to the {gamma}-ray flux assuming both power-law spectra and representative spectra from WIMP annihilation. The resulting integral flux above 100 MeV is constrained to be at a level below around 10{sup -9} photons cm{sup -2}s{sup -1}. Using recent stellar kinematic data, the {gamma}-ray flux limits are combined with improved determinations of the dark matter density profile in 8 of the 14 candidate dwarfs to place limits on the pair annihilation cross-section ofWIMPs in several widely studied extensions of the standard model, including its supersymmetric extension and other models that received recent attention. With the present data, we are able to rule out large parts of the parameter space where the thermal relic density is below the observed cosmological dark matter density and WIMPs (neutralinos here) are dominantly produced non-thermally, e.g. in models where supersymmetry breaking occurs via anomaly mediation. The {gamma}-ray limits presented here also constrain some WIMP models proposed to explain the Fermi and PAMELA e{sup +}e{sup -} data, including low-mass wino-like neutralinos and models with TeV masses pair-annihilating into muon-antimuon pairs.

Abdo, A.A.; Ackermann, M.; Ajello, M.; Atwood, W.B.; Baldini, L.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Bechtol, K.; Bellazzini, R.; Berenji, B.; Bloom, E.D.; Bonamente, E.; Borgland, A.W.; Bregeon, J.; Brez, A.; Brigida, M.; Bruel, P.; Burnett, T.H.; Buson, S.; Caliandro, G.A.; /Naval Research Lab, Wash., D.C. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /SLAC /UC, Santa Cruz /INFN, Pisa /DAPNIA, Saclay /INFN, Trieste /Trieste U. /INFN, Padua /Padua U. /INFN, Perugia /Perugia U. /Bari Polytechnic /INFN, Bari /Ecole Polytechnique /Washington U., Seattle /IASF, Milan /George Mason U. /NASA, Goddard

2010-05-26T23:59:59.000Z

263

Fermi edge singularities in the mesoscopic regime: Anderson orthogonality catastrophe Martina Hentschel,1,2 Denis Ullmo,1,  

E-Print Network [OSTI]

, such as quantum dots or nanoparticles, we study the Anderson orthogo- nality catastrophe AOC and Fermi-edge singularities in photoabsorption spectra in a series of two papers. In the present paper we focus on AOC for a finite number of particles in discrete energy levels where, in contrast to the bulk situation, AOC

Baranger, Harold U.

264

ccsd-00001419,version1-5Apr2004 Coherence and correlation properties of a one-dimensional attractive Fermi gas  

E-Print Network [OSTI]

-dimensional attractive Fermi gas Iacopo Carusotto1, 2 and Yvan Castin1, 1 Laboratoire Kastler Brossel, ´Ecole Normale to a condensate of pairs can be identified as the first-order pair coherence extending throughout the whole size of neutral atoms have opened the way to the realization of fermionic atomic samples at temperatures well

Paris-Sud XI, Université de

265

Self-Consistent Fermi-Liquid Properties and Density of States for Nuclear Many-Body Approximations  

Science Journals Connector (OSTI)

......Properties and Density of States for Nuclear Many-Body Approximations...compression modulus, symmetry energy and Landau parameters. We...Fermi surface by discussing nuclear matter approximations in terms...observable to be determined from nuclear many-body approximations......

Hiroshi Uechi

1991-07-01T23:59:59.000Z

266

Condition on the KohnSham kinetic energy and modern parametrization of the ThomasFermi density  

E-Print Network [OSTI]

; published online 20 January 2009 We study the asymptotic expansion of the neutral-atom energy as the atomic-correlation energy, EXC n , must be approximated. But a direct, orbital-free DFT could be constructed if onlyCondition on the Kohn­Sham kinetic energy and modern parametrization of the Thomas­Fermi density

Burke, Kieron

267

Dipole oscillations in Bose-Fermi mixtures in the time-dependent Gross-Pitaevskii and Vlasov equations  

E-Print Network [OSTI]

Dipole oscillations in Bose-Fermi mixtures in the time-dependent Gross-Pitaevskii and Vlasov equations Tomoyuki Maruyama1,2,3 and George F. Bertsch1 1 Institute for Nuclear Theory, University with the time-dependent Gross-Pitaevskii equation and the Vlasov equation. While the Bose gas oscillates

Bertsch George F.

268

Low-energy effective theory of Fermi surface coupled with U(1) gauge field in 2+1 dimensions  

SciTech Connect (OSTI)

We study the low-energy effective theory for a non-Fermi-liquid state in 2+1 dimensions, where a transverse U(1) gauge field is coupled with a patch of Fermi surface with N flavors of fermion in the large N limit. In the low-energy limit, quantum corrections are classified according to the genus of the two-dimensional surface on which Feynman diagrams can be drawn without a crossing in a double line representation and all planar diagrams are important in the leading order. The emerging theory has the similar structure to the four-dimensional SU(N) gauge theory in the large N limit. Because of strong quantum fluctuations caused by the abundant low-energy excitations near the Fermi surface, low-energy fermions remain strongly coupled even in the large N limit. As a result, there are infinitely many quantum corrections that contribute to the leading frequency dependence of the Green's function of fermion on the Fermi surface. On the contrary, the boson self-energy is not modified beyond the one-loop level and the theory is stable in the large N limit. The nonperturbative nature of the theory also shows up in correlation functions of gauge-invariant operators.

Lee, Sung-Sik [Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, L8S 4M1 (Canada)

2009-10-15T23:59:59.000Z

269

The Needle in the 100 deg2 Haystack: Uncovering Afterglows of Fermi GRBs with the Palomar Transient Factory  

E-Print Network [OSTI]

The Fermi Gamma-Ray Space Telescope has greatly expanded the number and energy window of observations of gamma-ray bursts (GRBs). However, the coarse localizations of tens to a hundred square degrees provided by the Fermi Gamma-ray Burst Monitor (GBM) instrument have posed a formidable obstacle to locating the bursts' host galaxies, measuring their redshifts, and tracking their panchromatic afterglows. We have built a target of opportunity mode for the intermediate Palomar Transient Factory (iPTF) in order to perform targeted searches for Fermi afterglows. Here, we present the results of one year of this program: eight afterglow discoveries, two of which (GRBs 130702A and 140606B) were at low redshift (z=0.145 and 0.384 respectively) and had spectroscopically confirmed broad-line type Ic supernovae. We present our broadband follow-up including spectroscopy as well as X-ray, UV, optical, millimeter, and radio observations. We study possible selection effects in the context of the total Fermi and Swift GRB samp...

Singer, Leo P; Cenko, S Bradley; Perley, Daniel A; Anderson, Gemma E; Anupama, G C; Arcavi, Iair; Bhalerao, Varun; Bue, Brian D; Cao, Yi; Connaughton, Valerie; Corsi, Alessandra; Cucchiara, Antonino; Fender, Rob P; Fox, Derek B; Gehrels, Neil; Goldstein, Adam; Gorosabel, J; Horesh, Assaf; Hurley, Kevin; Johansson, Joel; Kann, D A; Kouveliotou, Chryssa; Huang, Kuiyun; Kulkarni, S R; Masci, Frank; Nugent, Peter; Rau, Arne; Rebbapragada, Umaa D; Staley, Tim D; Svinkin, Dmitry; Thöne, C C; Postigo, A de Ugarte; Urata, Yuji; Weinstein, Alan

2015-01-01T23:59:59.000Z

270

Production of bosonic molecules in the nonequilibrium dynamics of a degenerate Fermi gas across a Feshbach resonance  

E-Print Network [OSTI]

In this thesis I present a nonequilibrium quantum field theory that describes the production of molecular dimers from a two-component quantum-degenerate atomic Fermi gas, via a linear downward sweep of a magnetic field across an s-wave Feshbach...

Dobrescu, Bogdan E.

2009-06-02T23:59:59.000Z

271

Neutron Physics A Revision of I. Halpern's Notes on E. Fermi's Lectures in 1945  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

'.. '.. iJNCLASSIFIED . UNITED x STATES ATOMIC ENERGY COMMISSION . 1 I~, ., AECD-2664 ,# NEUTRON PHYSICS A Revision of I. Halpern's Notes on E. Fermi's Lectures in 1945 BY J. G. Beckerley October 16, 1951 [TIS Issuance Date] Atomic Energy Commission New York Operations :L : 't to TIC ;iiiii *=c; Technical Information Service, Oak Ridge, Tennessee . _ .._ U,NCLASSlFIEB DISCLAIMER This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, make any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that

272

Fermi National Accelerator Laboratory FERMILAB-Conf-94/419-E  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Laboratory Laboratory FERMILAB-Conf-94/419-E CDF The Top.. . is it There? A Survey of the CDF and DO Experiments A.V. Tollestrup Fermi National Accelerator Laboratory P.O. Box 500, Batauia, Illinois 60510 December 1994 Published Proceedings Frontiers in Particle Physics, Cargese 94, Institu D'Etudes Scientifiques de Cargese, Cargese, Corsica, August l-13, 1994 e Operated by Universities Research Association Inc. under Contract No. DE-AC02-76CH03000 with Uw United States DepMnent of Energy Disclaimer This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information,

273

Anomalous Fermi-Surface Dependent Pairing in a Self-Doped High-Tc Superconductor  

SciTech Connect (OSTI)

We report the discovery of a self-doped multi-layer high T{sub c} superconductor Ba{sub 2}Ca{sub 3}Cu{sub 4}O{sub 8}F{sub 2} (F0234) which contains distinctly different superconducting gap magnitudes along its two Fermi surface(FS) sheets. While formal valence counting would imply this material to be an undoped insulator, it is a self-doped superconductor with a T{sub c} of 60K, possessing simultaneously both electron- and hole-doped FS sheets. Intriguingly, the FS sheet characterized by the much larger gap is the electron-doped one, which has a shape disfavoring two electronic features considered to be important for the pairing mechanism: the van Hove singularity and the antiferromagnetic ({pi}/a, {pi}/a) scattering.

Chen, Y.

2010-05-03T23:59:59.000Z

274

Medium effects and the shear viscosity of the dilute Fermi gas away from the conformal limit  

E-Print Network [OSTI]

We study the shear viscosity of a dilute Fermi gas as a function of the scattering length in the vicinity of the unitarity limit. The calculation is based on kinetic theory, which provides a systematic approach to transport properties in the limit in which the fugacity $z=n\\lambda^3/2$ is small. Here, $n$ is the density of the gas and $\\lambda$ is the thermal wave length of the fermions. At leading order in the fugacity expansion the shear viscosity is independent of density, and the minimum shear viscosity is achieved at unitarity. At the next order medium effects modify the scattering amplitude as well as the quasi-particle energy and velocity. We show that these effects shift the minimum of the shear viscosity to the Bose-Einstein condensation (BEC) side of the resonance, in agreement with the result of recent experiments.

Bluhm, Marcus

2014-01-01T23:59:59.000Z

275

Holographic Thermalization, stability of AdS, and the Fermi-Pasta-Ulam-Tsingou paradox  

E-Print Network [OSTI]

For a real massless scalar field in general relativity with a negative cosmological constant, we uncover a large class of spherically symmetric initial conditions that are close to AdS, but whose numerical evolution does not result in black hole formation. According to the AdS/CFT dictionary, these bulk solutions are dual to states of a strongly interacting boundary CFT that fail to thermalize at late times. Furthermore, as these states are not stationary, they define dynamical CFT configurations that do not equilibrate. We develop a two-timescale perturbative formalism that captures both direct and inverse cascades of energy and agrees with our fully nonlinear evolutions in the appropriate regime. We also show that this formalism admits a large class of quasi-periodic solutions. Finally, we demonstrate a striking parallel between the dynamics of AdS and the classic Fermi-Pasta-Ulam-Tsingou problem.

Venkat Balasubramanian; Alex Buchel; Stephen R. Green; Luis Lehner; Steven L. Liebling

2014-03-25T23:59:59.000Z

276

FERMI LIMIT ON THE NEUTRINO FLUX FROM GAMMA-RAY BURSTS  

SciTech Connect (OSTI)

If gamma-ray bursts (GRBs) produce high-energy cosmic rays, neutrinos are expected to be generated in GRBs via photo-pion productions. However, we stress that the same process also generates electromagnetic (EM) emission induced by the secondary electrons and photons, and that the EM emission is expected to be correlated with neutrino flux. Using Fermi/Large Area Telescope results on gamma-ray flux from GRBs, the GRB neutrino emission is limited to be <20 GeV m{sup -2} per GRB event on average, which is independent of the unknown GRB proton luminosity. This neutrino limit suggests that IceCube, operating at full scale, requires stacking of more than 130 GRBs in order to detect one GRB muon neutrino.

Li Zhuo [Department of Astronomy and Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing (China); Key Laboratory for the Structure and Evolution of Celestial Objects, Chinese Academy of Sciences, Kunming (China)

2013-06-20T23:59:59.000Z

277

MAGNETICALLY AND BARYONICALLY DOMINATED PHOTOSPHERIC GAMMA-RAY BURST MODEL FITS TO FERMI-LAT OBSERVATIONS  

SciTech Connect (OSTI)

We consider gamma-ray burst models where the radiation is dominated by a photospheric region providing the MeV Band spectrum, and an external shock region responsible for the GeV radiation via inverse Compton scattering. We parameterize the initial dynamics through an acceleration law {Gamma}{proportional_to}r {sup {mu}}, with {mu} between 1/3 and 1 to represent the range between an extreme magnetically dominated and a baryonically dominated regime, depending also on the magnetic field configuration. We compare these models to several bright Fermi-LAT bursts, and show that both the time-integrated and the time-resolved spectra, where available, can be well described by these models. We discuss the parameters which result from these fits, and discuss the relative merits and shortcomings of the two models.

Veres, Peter; Meszaros, Peter [Department of Astronomy and Astrophysics, Department of Physics, and Center for Particle and Gravitational Astrophysics, Pennsylvania State University, 525 Davey Lab, University Park, PA 16802 (United States)] [Department of Astronomy and Astrophysics, Department of Physics, and Center for Particle and Gravitational Astrophysics, Pennsylvania State University, 525 Davey Lab, University Park, PA 16802 (United States); Zhang, Bin-Bin, E-mail: veresp@psu.edu [Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Lab, University Park, PA 16802 (United States)] [Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Lab, University Park, PA 16802 (United States)

2013-02-10T23:59:59.000Z

278

Phase diagrams of one-dimensional Bose-Fermi mixtures of ultracold atoms  

Science Journals Connector (OSTI)

We study the quantum phase diagrams of Bose-Fermi mixtures of ultracold atoms confined to one dimension in an optical lattice. For systems with incommensurate densities, various quantum phases, e.g., spin- or charge-density waves, pairing, phase separation, and the Wigner crystal, are found to be dominant in different parameter regimes within a bosonization approach. The structure of the phase diagram leads us to propose that the system is best understood as a Luttinger liquid of polarons (i.e., atoms of one species surrounded by screening clouds of the other species). Special fillings, half filling for fermions, and unit filling for bosons, and the resulting gapped phases are also discussed, as well as the properties of the polarons and the experimental realization of these phases.

L. Mathey and D.-W. Wang

2007-01-10T23:59:59.000Z

279

Fermi Limit on the Neutrino Flux from Gamma-ray Bursts  

E-Print Network [OSTI]

If gamma-ray bursts (GRBs) produce high energy cosmic rays, neutrinos are expected to be generated in GRBs due to photo-pion productions. However we stress that the same process also generates electromagnetic (EM) emission induced by the production of secondary electrons and photons, and that the EM emission is expected to be correlated to the neutrino flux. Using the Fermi/LAT observational results on gamma-ray flux from GRBs, the GRB neutrino emission is limited to be below ~20 GeV/m^2 per GRB event on average, which is independent of the unknown GRB proton luminosity. This neutrino limit suggests that the full IceCube needs stacking more than 130 GRBs in order to detect one GRB muon neutrino.

Zhuo Li

2012-10-24T23:59:59.000Z

280

Bloch band and Bloch waves of superfluid Fermi gases in optical lattices  

Science Journals Connector (OSTI)

Bloch band and stabilities of Bloch waves of superfluid Fermi gases in one-dimensional (1D) periodic optical lattices are discussed. Within the hydrodynamical theory and the two-mode approximation, the Bloch band structure, the energetic and dynamical instabilities of Bloch waves at the first Brilliouin zone are presented. The results show that, when the atom density is beyond a critical value, a loop structure in the Bloch band at the zone edge is developed along the BEC-BCS crossover. The Bloch band structure and the stabilities of Bloch waves are modified dramatically when the system crosses from the BEC side to the BCS side, and they can be adjusted to the required characteristics by changing the atom’s interaction (with the Feshbach resonance technique), the atom density, and the lattice parameters. The analytical expressions of the critical atom density for exciting the loop structure and maintaining the stabilities of Bloch waves are obtained.

Wei Qi and Ju-Kui Xue

2010-01-12T23:59:59.000Z

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281

Spectrometer for X-ray emission experiments at FERMI free-electron-laser  

SciTech Connect (OSTI)

A portable and compact photon spectrometer to be used for photon in-photon out experiments, in particular x-ray emission spectroscopy, is presented. The instrument operates in the 25–800 eV energy range to cover the full emissions of the FEL1 and FEL2 stages of FERMI. The optical design consists of two interchangeable spherical varied-lined-spaced gratings and a CCD detector. Different input sections can be accommodated, with/without an entrance slit and with/without an additional relay mirror, that allow to mount the spectrometer in different end-stations and at variable distances from the target area both at synchrotron and at free-electron-laser beamlines. The characterization on the Gas Phase beamline at ELETTRA Synchrotron (Italy) is presented.

Poletto, L., E-mail: poletto@dei.unipd.it; Frassetto, F.; Miotti, P. [CNR - Institute of Photonics and Nanotechnologies (CNR-IFN), via Trasea 7, I-35131 Padova (Italy); Di Cicco, A.; Iesari, F. [Physics Division, School of Science and Technology, Università di Camerino, I-62032 Camerino (Italy); Finetti, P. [ELETTRA - Sincrotrone Trieste, Basovizza Area Science Park, S. S. 14 - km 163,5, I-34149, Basovizza (TS) (Italy); Grazioli, C. [Department of Chemical and Pharmaceutical Sciences, University of Trieste, Via L. Giorgieri 1, I-34127 Trieste (Italy); CNR-Istituto Officina dei Materiali (CNR-IOM), Laboratorio TASC, I-34149 Trieste (Italy); Kivimäki, A. [CNR-Istituto Officina dei Materiali (CNR-IOM), Laboratorio TASC, I-34149 Trieste (Italy); Stagira, S. [Politecnico di Milano – Department of Physics, I-20133 Milano (Italy); Coreno, M. [ELETTRA - Sincrotrone Trieste, Basovizza Area Science Park, S. S. 14 - km 163,5, I-34149, Basovizza (TS) (Italy); CNR – Istituto di Struttura della Materia (CNR-ISM), UOS Basovizza, I-34149 Trieste (Italy)

2014-10-15T23:59:59.000Z

282

Superfluidity in a three-flavor Fermi gas with SU(3) symmetry  

SciTech Connect (OSTI)

We investigate the superfluidity and the associated Nambu-Goldstone modes in a three-flavor atomic Fermi gas with SU(3) global symmetry. The s-wave pairing occurs in flavor antitriplet channel due to the Pauli principle, and the superfluid state contains both gapped and gapless fermionic excitations. Corresponding to the spontaneous breaking of the SU(3) symmetry to a SU(2) symmetry with five broken generators, there are only three Nambu-Goldstone modes, one is with linear dispersion law and two are with quadratic dispersion law. The other two expected Nambu-Goldstone modes become massive with a mass gap of the order of the fermion energy gap in a wide coupling range. The abnormal number of Nambu-Goldstone modes, the quadratic dispersion law, and the mass gap have significant effect on the low-temperature thermodynamics of the matter.

He Lianyi; Jin Meng; Zhuang Pengfei [Physics Department, Tsinghua University, Beijing 100084 (China)

2006-09-15T23:59:59.000Z

283

Signals of Bose Einstein condensation and Fermi quenching in the decay of hot nuclear systems  

E-Print Network [OSTI]

We report experimental signals of Bose-Einstein condensation in the decay of hot Ca projectile-like sources produced in mid-peripheral collisions at sub-Fermi energies. The experimental setup, constituted by the coupling of the INDRA 4$\\pi$ detector array to the forward angle VAMOS magnetic spectrometer, allowed us to reconstruct the mass, charge and excitation energy of the decaying hot projectile-like sources. Furthermore, by means of quantum fluctuation analysis techniques, temperatures and mean volumes per particle "as seen by" bosons and fermions separately are correlated to the excitation energy of the reconstructed system. The obtained results are consistent with the production of dilute mixed (bosons/fermions) systems, where bosons experience a smaller volume as compared to the surrounding fermionic gas. Our findings recall similar phenomena observed in the study of boson condensates in atomic traps.

Marini, P; Boisjoli, M; Verde, G; Chbihi, A; Ademard, G; Auger, L; Bhattacharya, C; Borderie, B; Bougault, R; Frankland, J; Galichet, E; Gruyer, D; Kundu, S; La Commara, M; Lombardo, I; Lopez, O; Mukherjee, G; Napolitani, P; Parlog, M; Rivet, M F; Rosato, E; Roy, R; Spadaccini, G; Vigilante, M; Wigg, P C; Bonasera, A

2015-01-01T23:59:59.000Z

284

Microphysics of Neutron Star Outer Envelopes in the Periodized, Magnetic Thomas-Fermi Model  

E-Print Network [OSTI]

Observations of several types of neutron stars indicate surface temperature inhomogeneities. In recent years magneto-thermal simulations have supported the idea that the magnetic field and anisotropic heat conduction play important roles in generating these inhomogeneities. Simulations rely on crustal microphysics input heretofore calculated at the level of a plasma model -- neglecting lattice structure and electron polarizability. We focus on the low density outer envelope, treating both of these elements by a proper periodization of the magnetic Thomas-Fermi model. Our solution method involves a novel domain decomposition and we describe a scalable implementation using \\textit{Hypre}. The method may be seen as a prototype for the general class of problems involving nonlinear charge screening of periodic, quasi-low-dimensionality structures, e.g. liquid crystals. Findings include low density $c'<0$ elastic instabilities for both bcc and fcc lattices, reminiscent of the situation in some light actinides, a...

Engstrom, Tyler A; Owen, Benjamin J; Brannick, James; Hu, Xiaozhe

2014-01-01T23:59:59.000Z

285

Bose and Fermi gases in the early Universe with self-gravitational effect  

SciTech Connect (OSTI)

We study the self-gravitational effect on the equation of state (EoS) of Bose and Fermi gases in thermal equilibrium at the end of reheating, the period after quark-hadron transition and before big bang nucleosynthesis (BBN). After introducing new grand canonical partition functions based on the work of Uhlenbeck and Gropper, we notice some interesting features of the newly developed EoSs with distinct behaviors of relativistic and nonrelativistic gases under self-gravity. The usual negligence of the self-gravitational effect when solving the background expansion of the early Universe is justified with numerical results, showing the magnitude of the self-gravitational modification of the state constant to be less than O(10{sup -78}). This helps us to clarify the background thermal evolution of the primordial patch. Such clarification is crucial in testing gravity theories, evaluating inflation models and determining element abundances in BBN.

Niu Yuezhen; Huang Junwu; Ma Boqiang [School of Physics and State Keye Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China); School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China) and Center for High Energy Physics, Peking University, Beijing 100871 (China) and Center for History and Philosophy of Science, Peking University, Beijing 100871 (China)

2011-03-15T23:59:59.000Z

286

Current Research at the University of Chicago Enrico Fermi Institute and James Franck Institute  

ScienceCinema (OSTI)

These talks will give an overview of physics research at the University of Chicago centered in two research institutes. The Enrico Fermi Institute pursues research in some core areas of the physical sciences. These include cosmology, particle physics, theoretical physics, particle astrophysics, and cosmochemistry. The EFI talk will focus on some examples of these activities which together will provide a broad overview of EFI science. Research at the James Franck Institute centers on the intersection between physics, chemistry and materials science, with the aim to unravel the complex connections between structure and dynamics in condensed matter systems. The JFI is also home to the Chicago Materials Research Science and Engineering Center. The JFI talk will provide highlights of current projects by JFI members.

Simon Swordy

2010-01-08T23:59:59.000Z

287

Signals of Bose Einstein condensation and Fermi quenching in the decay of hot nuclear systems  

E-Print Network [OSTI]

We report experimental signals of Bose-Einstein condensation in the decay of hot Ca projectile-like sources produced in mid-peripheral collisions at sub-Fermi energies. The experimental setup, constituted by the coupling of the INDRA 4$\\pi$ detector array to the forward angle VAMOS magnetic spectrometer, allowed us to reconstruct the mass, charge and excitation energy of the decaying hot projectile-like sources. Furthermore, by means of quantum fluctuation analysis techniques, temperatures and mean volumes per particle "as seen by" bosons and fermions separately are correlated to the excitation energy of the reconstructed system. The obtained results are consistent with the production of dilute mixed (bosons/fermions) systems, where bosons experience a smaller volume as compared to the surrounding fermionic gas. Our findings recall similar phenomena observed in the study of boson condensates in atomic traps.

P. Marini; H. Zheng; M. Boisjoli; G. Verde; A. Chbihi; G. Ademard; L. Auger; C. Bhattacharya; B. Borderie; R. Bougault; J. Frankland; E. Galichet; D. Gruyer; S. Kundu; M. La Commara; I. Lombardo; O. Lopez; G. Mukherjee; P. Napolitani; M. Parlog; M. F. Rivet; E. Rosato; R. Roy; G. Spadaccini; M. Vigilante; P. C. Wigg; A. Bonasera

2015-01-03T23:59:59.000Z

288

Test of the low-energy model for one-dimensional interacting Fermi systems  

Science Journals Connector (OSTI)

Bosonization predicts that the specific heat C(T) of a one-dimensional interacting Fermi system is a sum of the specific heats of free collective charge and spin excitations, plus the term with the running backscattering amplitude which flows to zero logarithmically with decreasing T. We verify whether this result is reproduced in the g-ology model. Of specific interest are the anomalous terms in C(T) that depend on the bare backscattering amplitude. We show that these terms can be incorporated into a renormalized spin velocity. We do this by proving the equivalence of the results for C(T) obtained within the g-ology model and by bosonization with velocities obtained by the numerical solution of the Bethe-ansatz equations for the Hubbard model.

Andrey V. Chubukov; Dmitrii L. Maslov; Fabian H. L. Essler

2008-04-14T23:59:59.000Z

289

Cosmic ray acceleration in supernova remnants and the FERMI/PAMELA data  

Science Journals Connector (OSTI)

We discuss recent observations of high energy cosmic ray positrons and electrons in the context of hadronic interactions in supernova remnants (SNRs), the suspected accelerators of galactic cosmic rays. Diffusive shock acceleration can harden the energy spectrum of secondary positrons relative to that of the primary protons and electrons and thus explain the rise in the positron fraction observed by PAMELA above 10 GeV. We normalize the hadronic interaction rate by holding pion decay to be responsible for the gamma rays detected by HESS from some SNRs. By simulating the spatial and temporal distribution of SNRs in the Galaxy according to their known statistics, we are able to then fit the electron (plus positron) energy spectrum measured by Fermi. It appears that IceCube has good prospects for detecting the hadronic neutrino fluxes expected from nearby SNRs.

Markus Ahlers; Philipp Mertsch; Subir Sarkar

2009-12-29T23:59:59.000Z

290

Phonon contribution to the shear viscosity of a superfluid Fermi gas in the unitarity limit  

SciTech Connect (OSTI)

We present a detailed analysis of the contribution of small-angle Nambu–Goldstone boson (phonon) collisions to the shear viscosity, ?, in a superfluid atomic Fermi gas close to the unitarity limit. We show that the experimental values of the shear viscosity coefficient to entropy ratio, ?/s, obtained at the lowest reached temperature can be reproduced assuming that phonons give the leading contribution to ?. The phonon contribution is evaluated considering 1?2 processes and taking into account the finite size of the experimental system. In particular, for very low temperatures, T?0.1T{sub F}, we find that phonons are ballistic and the contribution of phonons to the shear viscosity is determined by the processes that take place at the interface between the superfluid and the normal phase. This result is independent of the detailed form of the phonon dispersion law and leads to two testable predictions: the shear viscosity should correlate with the size of the optical trap and it should decrease with decreasing temperature. For higher temperatures the detailed form of the phonon dispersion law becomes relevant and, within our model, we find that the experimental data for ?/s can be reproduced assuming that phonons have an anomalous dispersion law. -- Highlights: •We study the contribution of phonons to shear viscosity of a cold Fermi gas at unitary. •The shear viscosity to entropy ratio (?/s) is reproduced for T?0.1T{sub F} assuming an anomalous dispersion law for phonons.

Mannarelli, Massimo [I.N.F.N., Laboratori Nazionali del Gran Sasso, Assergi (AQ) (Italy)] [I.N.F.N., Laboratori Nazionali del Gran Sasso, Assergi (AQ) (Italy); Manuel, Cristina [Instituto de Ciencias del Espacio (IEEC/CSIC), Campus Universitat Autònoma de Barcelona, Facultat de Ciències, Torre C5, E-08193 Bellaterra (Barcelona) (Spain)] [Instituto de Ciencias del Espacio (IEEC/CSIC), Campus Universitat Autònoma de Barcelona, Facultat de Ciències, Torre C5, E-08193 Bellaterra (Barcelona) (Spain); Tolos, Laura, E-mail: tolos@ice.csic.es [Instituto de Ciencias del Espacio (IEEC/CSIC), Campus Universitat Autònoma de Barcelona, Facultat de Ciències, Torre C5, E-08193 Bellaterra (Barcelona) (Spain) [Instituto de Ciencias del Espacio (IEEC/CSIC), Campus Universitat Autònoma de Barcelona, Facultat de Ciències, Torre C5, E-08193 Bellaterra (Barcelona) (Spain); Frankfurt Institute for Advanced Studies, Johann Wolfgang Goethe University, Ruth-Moufang-Str. 1, 60438 Frankfurt am Main (Germany)

2013-09-15T23:59:59.000Z

291

THE LUMINOSITY FUNCTION OF FERMI-DETECTED FLAT-SPECTRUM RADIO QUASARS  

SciTech Connect (OSTI)

Fermi has provided the largest sample of {gamma}-ray-selected blazars to date. In this work we use a complete sample of flat spectrum radio quasars (FSRQs) detected during the first year of operation to determine the luminosity function (LF) and its evolution with cosmic time. The number density of FSRQs grows dramatically up to redshift {approx}0.5-2.0 and declines thereafter. The redshift of the peak in the density is luminosity dependent, with more luminous sources peaking at earlier times; thus the LF of {gamma}-ray FSRQs follows a luminosity-dependent density evolution similar to that of radio-quiet active galactic nuclei. Also, using data from the Swift Burst Alert Telescope we derive the average spectral energy distribution (SED) of FSRQs in the 10 keV-300 GeV band and show that there is no correlation between the luminosity at the peak of the {gamma}-ray emission component and its peak frequency. Using this luminosity-independent SED with the derived LF allows us to predict that the contribution of FSRQs to the Fermi isotropic {gamma}-ray background is 9.3{sup +1.6}{sub -1.0}% ({+-}3% systematic uncertainty) in the 0.1-100 GeV band. Finally we determine the LF of unbeamed FSRQs, finding that FSRQs have an average Lorentz factor of {gamma} = 11.7{sup +3.3}{sub -2.2}, that most are seen within 5 Degree-Sign of the jet axis, and that they represent only {approx}0.1% of the parent population.

Ajello, M.; Shaw, M. S.; Romani, R. W.; Costamante, L.; Reimer, A. [W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States); Dermer, C. D. [Space Science Division, Naval Research Laboratory, Washington, DC 20375-5352 (United States); King, O. G.; Max-Moerbeck, W.; Readhead, A.; Richards, J. L.; Stevenson, M., E-mail: majello@slac.stanford.edu, E-mail: msshaw@stanford.edu, E-mail: rwr@astro.stanford.edu [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States)

2012-06-01T23:59:59.000Z

292

Strong-coupling ansatz for the one-dimensional Fermi gas in a harmonic potential  

E-Print Network [OSTI]

The one-dimensional (1D) Fermi gas with repulsive short-range interactions provides an important model of strong correlations and is often amenable to exact methods. However, in the presence of confinement, no exact solution is known for an arbitrary number of strongly interacting fermions. Here, we propose a novel ansatz for generating the lowest-energy wavefunctions of the repulsive 1D Fermi gas in a harmonic potential near the Tonks-Girardeau (TG) limit of infinite interactions. We specialize to the case of a single impurity interacting with $N$ majority particles, where we may derive analytic forms of the approximate wavefunctions. Comparing with exact numerics, we show that the overlap between the wavefunctions from our ansatz and the exact ones in the ground-state manifold exceeds 0.9997 for $N\\leq8$. Moreover, the overlap for the ground-state wavefunction extrapolates to 0.9999 as $N\\to\\infty$. Thus our ansatz is essentially indistinguishable from numerically exact results in both the few- and many-body limits. In the large $N$ limit, we find that the impurity probability density in the ground state is only slightly perturbed by the infinitely repulsive interactions, while the quasiparticle residue vanishes as the many-body limit is approached, reflecting the Anderson orthogonality catastrophe. We derive an effective Heisenberg spin-chain model for the regime near the TG limit, within which our ansatz is exact. Here, we find that the impurity eigenstates in the spin basis correspond to discrete Chebyshev polynomials. The energy of states in excited manifolds is calculated using a dynamical SO(2,1) symmetry, which provides an exact relation between states related by a scaling transformation. We finally show how our results for the wavefunctions and the energy spectrum can be detected in cold atomic gases via collective-mode, tunneling, and radio-frequency experiments.

Jesper Levinsen; Pietro Massignan; Georg M. Bruun; Meera M. Parish

2014-08-29T23:59:59.000Z

293

Limits on large extra dimensions based on observations of neutron stars with the Fermi-LAT  

SciTech Connect (OSTI)

We present limits for the compactification scale in the theory of Large Extra Dimensions (LED) proposed by Arkani-Hamed, Dimopoulos, and Dvali. We use 11 months of data from the Fermi Large Area Telescope (Fermi-LAT) to set gamma ray flux limits for 6 gamma-ray faint neutron stars (NS). To set limits on LED we use the model of Hannestad and Raffelt (HR) that calculates the Kaluza-Klein (KK) graviton production in supernova cores and the large fraction subsequently gravitationally bound around the resulting NS. The predicted decay of the bound KK gravitons to ?? should contribute to the flux from NSs. Considering 2 to 7 extra dimensions of the same size in the context of the HR model, we use Monte Carlo techniques to calculate the expected differential flux of gamma-rays arising from these KK gravitons, including the effects of the age of the NS, graviton orbit, and absorption of gamma-rays in the magnetosphere of the NS. We compare our Monte Carlo-based differential flux to the experimental differential flux using maximum likelihood techniques to obtain our limits on LED. Our limits are more restrictive than past EGRET-based optimistic limits that do not include these important corrections. Additionally, our limits are more stringent than LHC based limits for 3 or fewer LED, and comparable for 4 LED. We conclude that if the effective Planck scale is around a TeV, then for 2 or 3 LED the compactification topology must be more complicated than a torus.

Ajello, M.; Bechtol, K.; Berenji, B.; Bloom, E.D.; Borgland, A.W.; Buehler, R.; Cameron, R.A. [W.W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States); Baldini, L.; Bellazzini, R.; Bregeon, J. [INFN — Sezione di Pisa, I-56127 Pisa (Italy); Barbiellini, G. [INFN — Sezione di Trieste, I-34127 Trieste (Italy); Bastieri, D.; Buson, S. [INFN — Sezione di Padova, I-35131 Padova (Italy); Bonamente, E.; Cecchi, C. [INFN — Sezione di Perugia, I-06123 Perugia (Italy); Brigida, M. [Dipartimento di Fisica 'M. Merlin' dell'Università e del Politecnico di Bari, I-70126 Bari (Italy); Bruel, P. [Laboratoire Leprince-Ringuet, École polytechnique, CNRS/IN2P3, Palaiseau (France); Caliandro, G.A. [Institut de Ciències de l'Espai (IEEE-CSIC), Campus UAB, 08193 Barcelona (Spain); Caraveo, P.A. [INAF-Istituto di Astrofisica Spaziale e Fisica Cosmica, I-20133 Milano (Italy); Casandjian, J.M., E-mail: bijanb@alumni.stanford.edu, E-mail: elliott@slac.stanford.edu, E-mail: johann.cohen-tanugi@lupm.in2p3.fr [Laboratoire AIM, CEA-IRFU/CNRS/Université Paris Diderot, Service d'Astrophysique, CEA Saclay, 91191 Gif sur Yvette (France); Collaboration: Fermi-LAT collaboration; and others

2012-02-01T23:59:59.000Z

294

Limits on Large Extra Dimensions Based on Observations of Neutron Stars with the Fermi-LAT  

SciTech Connect (OSTI)

We present limits for the compactification scale in the theory of Large Extra Dimensions (LED) proposed by Arkani-Hamed, Dimopoulos, and Dvali. We use 11 months of data from the Fermi Large Area Telescope (Fermi-LAT) to set gamma ray flux limits for 6 gamma-ray faint neutron stars (NS). To set limits on LED we use the model of Hannestad and Raffelt (HR) that calculates the Kaluza-Klein (KK) graviton production in supernova cores and the large fraction subsequently gravitationally bound around the resulting NS. The predicted decay of the bound KK gravitons to {gamma}{gamma} should contribute to the flux from NSs. Considering 2 to 7 extra dimensions of the same size in the context of the HR model, we use Monte Carlo techniques to calculate the expected differential flux of gamma-rays arising from these KK gravitons, including the effects of the age of the NS, graviton orbit, and absorption of gamma-rays in the magnetosphere of the NS. We compare our Monte Carlo-based differential flux to the experimental differential flux using maximum likelihood techniques to obtain our limits on LED. Our limits are more restrictive than past EGRET-based optimistic limits that do not include these important corrections. Additionally, our limits are more stringent than LHC based limits for 3 or fewer LED, and comparable for 4 LED. We conclude that if the effective Planck scale is around a TeV, then for 2 or 3 LED the compactification topology must be more complicated than a torus.

Ajello, M.; /SLAC /KIPAC, Menlo Park; Baldini, L.; /INFN, Pisa; Barbiellini, G.; /INFN, Trieste /Trieste U.; Bastieri, D.; /INFN, Padua /Padua U.; Bechtol, K.; /SLAC /KIPAC, Menlo Park; Bellazzini, R.; /INFN, Pisa; Berenji, B.; /SLAC /KIPAC, Menlo Park; Bloom, E.D.; /SLAC /KIPAC, Menlo Park; Bonamente, E.; /INFN, Perugia /Perugia U.; Borgland, A.W.; /SLAC /KIPAC, Menlo Park; Bregeon, J.; /INFN, Pisa; Brigida, M.; /Bari Polytechnic /INFN, Bari; Bruel, P.; /Ecole Polytechnique; Buehler, R.; /SLAC /KIPAC, Menlo Park; Buson, S.; /INFN, Padua /Padua U.; Caliandro, G.A.; /CSIC, Catalunya; Cameron, R.A.; /SLAC /KIPAC, Menlo Park; Caraveo, P.A.; /Brera Observ.; Casandjian, J.M.; /AIM, Saclay; Cecchi, C.; /INFN, Perugia /Perugia U.; Charles, E.; /SLAC /KIPAC, Menlo Park /Naval Research Lab, Wash., D.C. /SLAC /KIPAC, Menlo Park /ASDC, Frascati /Perugia U. /SLAC /KIPAC, Menlo Park /Montpellier U. /Stockholm U. /Stockholm U., OKC /Royal Swedish Acad. Sci. /ASDC, Frascati /Udine U. /INFN, Trieste /Bari Polytechnic /INFN, Bari /Naval Research Lab, Wash., D.C. /SLAC /KIPAC, Menlo Park /SLAC /KIPAC, Menlo Park /SLAC /KIPAC, Menlo Park /SLAC /KIPAC, Menlo Park /Bari Polytechnic /INFN, Bari /Ecole Polytechnique /NASA, Goddard /Hiroshima U. /Bari Polytechnic /INFN, Bari /INFN, Bari /ASDC, Frascati /INFN, Perugia /Perugia U. /Bari Polytechnic /INFN, Bari /Bari Polytechnic /INFN, Bari /Bologna Observ. /SLAC /KIPAC, Menlo Park /SLAC /KIPAC, Menlo Park /SLAC /KIPAC, Menlo Park /AIM, Saclay /Alabama U., Huntsville /INFN, Padua; /more authors..

2012-08-17T23:59:59.000Z

295

THE FERMI BUBBLES. II. THE POTENTIAL ROLES OF VISCOSITY AND COSMIC-RAY DIFFUSION IN JET MODELS  

SciTech Connect (OSTI)

The origin of the Fermi bubbles recently detected by the Fermi Gamma-ray Space Telescope in the inner Galaxy is mysterious. In the companion paper Guo and Mathews (Paper I), we use hydrodynamic simulations to show that they could be produced by a recent powerful active galactic nucleus (AGN) jet event. Here, we further explore this scenario to study the potential roles of shear viscosity and cosmic-ray (CR) diffusion on the morphology and CR distribution of the bubbles. We show that even a relatively low level of viscosity ({mu}{sub visc} {approx}> 3 g cm{sup -1} s{sup -1}, or {approx}0.1%-1% of Braginskii viscosity in this context) could effectively suppress the development of Kelvin-Helmholtz instabilities at the bubble surface, resulting in smooth bubble edges as observed. Furthermore, viscosity reduces circulating motions within the bubbles, which would otherwise mix the CR-carrying jet backflow near bubble edges with the bubble interior. Thus viscosity naturally produces an edge-favored CR distribution, an important ingredient to produce the observed flat gamma-ray surface brightness distribution. Generically, such a CR distribution often produces a limb-brightened gamma-ray intensity distribution. However, we show that by incorporating CR diffusion that is strongly suppressed across the bubble surface (as inferred from sharp bubble edges) but is close to canonical values in the bubble interior, we obtain a reasonably flat gamma-ray intensity profile. The similarity of the resulting CR bubble with the observed Fermi bubbles strengthens our previous result in Paper I that the Fermi bubbles were produced by a recent AGN jet event. Studies of the nearby Fermi bubbles may provide a unique opportunity to study the potential roles of plasma viscosity and CR diffusion on the evolution of AGN jets and bubbles.

Guo Fulai; Mathews, William G. [UCO/Lick Observatory, Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Dobler, Gregory [Kavli Institute for Theoretical Physics, University of California, Santa Barbara Kohn Hall, Santa Barbara, CA 93106 (United States); Oh, S. Peng, E-mail: fulai@ucolick.org [Department of Physics, University of California, Santa Barbara Kohn Hall, Santa Barbara, CA 93106 (United States)

2012-09-10T23:59:59.000Z

296

Strongly three-dimensional electronic structure and Fermi surfaces of SrFe2(As0.65P0.35)2: Comparison with BaFe2(As1?xPx)2  

Science Journals Connector (OSTI)

The isovalent-substituted iron-pnictide superconductor SrFe2(As1?xPx)2 (x=0.35) has a slightly higher optimum critical temperature than the similar system BaFe2(As1?xPx)2, and its parent compound SrFe2As2 has a much higher Néel temperature than BaFe2As2. We have studied the band structure and the Fermi surfaces of optimally doped SrFe2(As1?xPx)2 by angle-resolved photoemission spectroscopy (ARPES). Three holelike Fermi surfaces (FSs) around (0,0) and two electronlike FSs around (?,?) have been observed as in the case of BaFe2(As1?xPx)2. Measurements with different photon energies have revealed that the outermost hole FS is more strongly warped along the kz direction than the corresponding one in BaFe(As1?xPx)2, and that the innermost one is an ellipsoidal pocket. The electron FSs are almost cylindrical, unlike the corrugated ones in BaFe(As1?xPx)2. A comparison of the ARPES data with a first-principles band-structure calculation revealed that the quasiparticle mass renormalization factors are different not only between bands of different orbital character, but also between the hole and electron FSs of the same orbital character. By examining the nesting conditions between the hole and electron FSs, we conclude that magnetic interactions between FeAs layers rather than FS nesting play an important role in stabilizing the antiferromagnetic order. The insensitivity of superconductivity to the FS nesting can be explained if only the dxy and/or dxz/yz orbitals are active in inducing superconductivity or if FS nesting is not important for superconductivity.

H. Suzuki; T. Kobayashi; S. Miyasaka; T. Yoshida; K. Okazaki; L. C. C. Ambolode; II; S. Ideta; M. Yi; M. Hashimoto; D. H. Lu; Z.-X. Shen; K. Ono; H. Kumigashira; S. Tajima; A. Fujimori

2014-05-30T23:59:59.000Z

297

Christmas burst reveals neutron star collision  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Christmas burst reveals neutron star collision Christmas burst reveals neutron star collision Christmas burst reveals neutron star collision Called the Christmas Burst, GRB 101225A was freakishly lengthy and it produced radiation at unusually varying wavelengths. December 1, 2011 Los Alamos National Laboratory sits on top of a once-remote mesa in northern New Mexico with the Jemez mountains as a backdrop to research and innovation covering multi-disciplines from bioscience, sustainable energy sources, to plasma physics and new materials. Los Alamos National Laboratory sits on top of a once-remote mesa in northern New Mexico with the Jemez mountains as a backdrop to research and innovation covering multi-disciplines from bioscience, sustainable energy sources, to plasma physics and new materials. Contact

298

Fish Population and Behavior Revealed by Instantaneous  

E-Print Network [OSTI]

Fish Population and Behavior Revealed by Instantaneous Continental Shelf­Scale Imaging Nicholas C-transect methods from slow-moving research vessels. These methods significantly undersample fish populations in time and space, leaving an incomplete and ambiguous record of abundance and behavior. We show that fish

299

Computer Simulations Reveal Multiple Functions for Aromatic  

E-Print Network [OSTI]

Computer Simulations Reveal Multiple Functions for Aromatic Residues in Cellulase Enzymes NREL researchers use high-performance computing to demonstrate fundamental roles of aromatic residues in cellulase enzyme tunnels. National Renewable Energy Laboratory (NREL) computer simulations of a key indus- trial

300

Bernard J. Baars How Brain Reveals Mind  

E-Print Network [OSTI]

Bernard J. Baars How Brain Reveals Mind Neural Studies Support the Fundamental Role of Conscious Experience Abstract: In the last decade, careful studies of the living brain have opened the way for human by seven cases: (1) the discovery of widespread brain activation during conscious perception; (2) high

Memphis, University of

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301

Education Office / Fermi National Accelerator Laboratory U. S. Department of Energy's Office of Science / Managed by Universities Research Association, Inc.  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Education Office / Fermi National Accelerator Laboratory Education Office / Fermi National Accelerator Laboratory U. S. Department of Energy's Office of Science / Managed by Universities Research Association, Inc. Kirk Road and Pine Street / M.S. 226 / P.O. Box 500 / Batavia, IL 60510 / 630.840.3092 / www-ed.fnal.gov Physics Workshop and Field Trip for Grades 6-9 Sampler Introduction "Beauty" and "Charm" are the fanciful names of two of six fundamental particles called quarks. Part of the experimental verification for the existence of quarks was carried out at Fermilab. However, this unit was titled Beauty and Charm at Fermilab with a second meaning in mind. Fermilab, as any visitor will attest, is a place of beauty-a high-rise main building with architec- ture inspired by a French cathedral and set on a prairie-like plain reminiscent of early Illinois. In

302

Superfluidity at the BEC-BCS crossover in two-dimensional Fermi gases with population and mass imbalance  

Science Journals Connector (OSTI)

We explore the zero-temperature phase behavior of a two-dimensional two-component atomic Fermi gas with population and mass imbalance in the regime of the BEC-BCS crossover. Working in the mean-field approximation, we show that the normal and homogeneous balanced superfluid phases are separated by an inhomogeneous superfluid phase of Fulde-Ferrel-Larkin-Ovchinnikov (FFLO) type. We obtain an analytical expression for the line of continuous transitions separating the normal and inhomogeneous FFLO phases. We further show that the transition from the FFLO phase to the homogeneous balanced superfluid is discontinuous leading to phase separation. If the species have different masses, the superfluid phase is favored when the lighter species is in excess. We explore the implications of these findings for the properties of the two-component Fermi gas in the atomic trap geometry. Finally, we compare and contrast our findings with the predicted phase behavior of the electron-hole bilayer system.

G. J. Conduit; P. H. Conlon; B. D. Simons

2008-05-29T23:59:59.000Z

303

Scattering of light and atoms in a Fermi-Dirac gas with Bardeen-Cooper-Schrieffer pairing  

Science Journals Connector (OSTI)

We theoretically study the optical properties of a Fermi-Dirac gas in the presence of a superfluid state. We calculate the leading quantum-statistical corrections to the standard column density result of the electric susceptibility. We also consider the Bragg diffraction of atoms by means of light-stimulated transitions of photons between two intersecting laser beams. Bardeen-Cooper-Schrieffer pairing between atoms in different internal levels magnifies incoherent scattering processes. The absorption linewidth of a Fermi-Dirac gas is broadened and shifted. Bardeen-Cooper-Schrieffer pairing introduces a collisional local-field shift that may dramatically dominate the Lorentz-Lorenz shift. For the case of the Bragg spectroscopy the static structure function may be significantly increased due to superfluidity in the near-forward scattering.

J. Ruostekoski

2000-02-10T23:59:59.000Z

304

Superscaling and Charge-Changing Neutrino Scattering from Nuclei in the $\\boldsymbol ?$-Region beyond the Relativistic Fermi Gas Model  

E-Print Network [OSTI]

The superscaling analysis using the scaling function obtained within the coherent density fluctuation model is extended to calculate charge-changing neutrino and antineutrino scattering on $^{12}$C at energies from 1 to 2 GeV not only in the quasielastic but also in the delta excitation region. The results are compared with those obtained using the scaling functions from the relativistic Fermi gas model and from the superscaling analysis of inclusive scattering of electrons from nuclei.

M. V. Ivanov; M. B. Barbaro; J. A. Caballero; A. N. Antonov; E. Moya de Guerra; M. K. Gaidarov

2008-02-29T23:59:59.000Z

305

Test of Fermi Gas Model and Plane-Wave Impulse Approximation Against Electron-Nucleus Scattering Data  

E-Print Network [OSTI]

A widely used relativistic Fermi gas model and plane-wave impulse approximation are tested against electron-nucleus scattering data. Inclusive quasi-elastic cross section are calculated and compared with high-precision data for C, O, and Ca. A dependence of agreement between calculated cross section and data on a momentum transfer is shown. Results for the C(nu_mu,mu) reaction are presented and compared with experimental data of the LSND collaboration.

A. V. Butkevich; S. P. Mikheyev

2005-04-30T23:59:59.000Z

306

Revisiting variable gamma-ray sky at 1 GeV with 6 years of Fermi-LAT data  

E-Print Network [OSTI]

We perform a blind search for the variability of the gamma-ray sky in the energy range E>1 GeV using 308 weeks of the Fermi-LAT data. We use the technique based on the comparison of the weekly photon counts and exposures in sky pixels by means of the Kolmogorov-Smirnov test. We consider the flux variations in the region significant if statistical probability of uniformity is less than $4\\times10^{-6}$, which corresponds to 0.05 false detections in the whole set of 12288 pixels. Close inspection of the detected variable regions result in identification of 8 sources without previous known variability. Two of them are included in the second Fermi LAT source catalogue (FBQS J122424.1+243623 and GB6 J0043+3426) and one (3EG J1424+3734) was reported by EGRET and also was included in the First Fermi LAT source catalogue (1FGL), but is missing in the 2FGL. Possible identifications of five other sources are obtained using NED and SIMBAD databases (1RXS J161939.9+765515, PMN J2320-6447, PKS 0226-559, PKS J0030-0211, PM...

Pshirkov, M S

2015-01-01T23:59:59.000Z

307

Gamma-Ray Observations of the Supernova Remnant RX J0852.0-4622 with the Fermi LAT  

SciTech Connect (OSTI)

We report on gamma-ray observations of the supernova remnant (SNR) RX J0852.0-4622 with the Large Area Telescope (LAT) aboard the Fermi Gamma-ray Space Telescope. In the Fermi LAT data, we find a spatially extended source at the location of the SNR. The extension is consistent with the SNR size seen in other wavelengths such as X-rays and TeV gamma rays, leading to the identification of the gamma-ray source with the SNR. The spectrum is well described as a power law with a photon index of {Lambda} = 1.85 {+-} 0.06 (stat){sub -0.19}{sup +0.18} (sys), which smoothly connects to the H.E.S.S. spectrum in the TeV energy band. We discuss the gamma-ray emission mechanism based on multiwavelength data. The broadband data can be fit well by a model in which the gamma rays are of hadronic origin. We also consider a scenario with inverse Compton scattering of electrons as the emission mechanism of the gamma rays. Although the leptonic model predicts a harder spectrum in the Fermi LAT energy range, the model can fit the data considering the statistical and systematic errors.

Tanaka, T.; Allafort, A.; /Stanford U., HEPL /KIPAC, Menlo Park; Ballet, J.; /Saclay; Funk, S.; /Stanford U., HEPL /KIPAC, Menlo Park; Giordano, F.; /Bari U. /INFN, Bari; Hewitt, J.; /NASA, Goddard; Lemoine-Goumard, M.; /Bordeaux U.; Tajima, H.; /Stanford U., HEPL /KIPAC, Menlo Park /Nagoya U., Solar-terrestrial Environ Lab.; Tibolla, O.; /Wurzburg U.; Uchiyama, Y.; /Stanford U., HEPL /KIPAC, Menlo Park

2011-12-13T23:59:59.000Z

308

The composition of the Fermi-LAT IGRB intensity: emission from extragalactic point sources and dark matter annihilations  

E-Print Network [OSTI]

A new estimation of the isotropic diffuse gamma-ray background (IGRB) observed by the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope (Fermi) has been presented for 50 months of data, in the energy range 100 MeV-820 GeV and for different modelings of the Galactic foreground. We attempt here the interpretation of the Fermi-LAT IGRB data in terms of the gamma-ray unresolved emission from different extragalactic populations. We find very good fits to the experimental IGRB, obtained with theoretical predictions for the emission from active galactic nuclei and star forming galaxies. In addition, we probe a possible emission coming from the annihilation of weakly interacting dark matter (DM) particles in the halo of our Galaxy. We set stringent limits on its annihilation cross section into gamma-rays, which are about the thermal relic value for a wide range of DM masses. We also identify regions in the DM mass and annihilation cross section parameter space which can significantly improve the...

Di Mauro, Mattia

2015-01-01T23:59:59.000Z

309

ALS Reveals New State of Matter  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

ALS Reveals New State of Matter Print ALS Reveals New State of Matter Print ALS user groups from Princeton and Stanford have been making waves this past year with several high-profile papers and extensive news coverage of their work on a new state of matter embodied by "topological insulators," materials that conduct electricity only on their surfaces. First identified at the ALS in 2007 by a Princeton team led by M. Zahid Hasan, topological insulators have been the subject of intense interest, based on unusual quantum properties that manifest themselves macroscopically. The discovery of a "second generation" of topological insulators that robustly retain these properties well above room temperature has spurred a rising tide of theoretical proposals for potential applications in nanoscale spintronic devices and fault-tolerant quantum computers. In addition, it's also been suggested that topological insulators may serve as a test bed for studies of never-before-seen particles predicted by high-energy physics.

310

ALS Reveals New State of Matter  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

ALS Reveals New State of Matter Print ALS Reveals New State of Matter Print ALS user groups from Princeton and Stanford have been making waves this past year with several high-profile papers and extensive news coverage of their work on a new state of matter embodied by "topological insulators," materials that conduct electricity only on their surfaces. First identified at the ALS in 2007 by a Princeton team led by M. Zahid Hasan, topological insulators have been the subject of intense interest, based on unusual quantum properties that manifest themselves macroscopically. The discovery of a "second generation" of topological insulators that robustly retain these properties well above room temperature has spurred a rising tide of theoretical proposals for potential applications in nanoscale spintronic devices and fault-tolerant quantum computers. In addition, it's also been suggested that topological insulators may serve as a test bed for studies of never-before-seen particles predicted by high-energy physics.

311

ALS Reveals New State of Matter  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

ALS Reveals New State of Matter Print ALS Reveals New State of Matter Print ALS user groups from Princeton and Stanford have been making waves this past year with several high-profile papers and extensive news coverage of their work on a new state of matter embodied by "topological insulators," materials that conduct electricity only on their surfaces. First identified at the ALS in 2007 by a Princeton team led by M. Zahid Hasan, topological insulators have been the subject of intense interest, based on unusual quantum properties that manifest themselves macroscopically. The discovery of a "second generation" of topological insulators that robustly retain these properties well above room temperature has spurred a rising tide of theoretical proposals for potential applications in nanoscale spintronic devices and fault-tolerant quantum computers. In addition, it's also been suggested that topological insulators may serve as a test bed for studies of never-before-seen particles predicted by high-energy physics.

312

A new approach to searching for dark matter signals in Fermi-LAT gamma rays  

SciTech Connect (OSTI)

Several cosmic ray experiments have measured excesses in electrons and positrons, relative to standard backgrounds, for energies from ? 10 GeV–1 TeV. These excesses could be due to new astrophysical sources, but an explanation in which the electrons and positrons are dark matter annihilation or decay products is also consistent. Fortunately, the Fermi-LAT diffuse gamma ray measurements can further test these models, since the electrons and positrons produce gamma rays in their interactions in the interstellar medium. Although the dark matter gamma ray signal consistent with the local electron and positron measurements should be quite large, as we review, there are substantial uncertainties in the modeling of diffuse backgrounds and, additionally, experimental uncertainties that make it difficult to claim a dark matter discovery. In this paper, we introduce an alternative method for understanding the diffuse gamma ray spectrum in which we take the intensity ratio in each energy bin of two different regions of the sky, thereby canceling common systematic uncertainties. For many spectra, this ratio fits well to a power law with a single break in energy. The two measured exponent indices are a robust discriminant between candidate models, and we demonstrate that dark matter annihilation scenarios can predict index values that require ''extreme'' parameters for background-only explanations.

Chang, Spencer [Physics Department, University of California Davis, One Shields Avenue, Davis, CA 95616 (United States); Goodenough, Lisa, E-mail: spchang@ucdavis.edu, E-mail: lcg261@nyu.edu [Center for Cosmology and Particle Physics, Department of Physics, New York University, 4 Washington Place, New York, NY 10003 (United States)

2010-08-01T23:59:59.000Z

313

Pulsed Gamma-rays from PSR J2021+3651 with the Fermi Large Area Telescope  

E-Print Network [OSTI]

We report the detection of pulsed gamma-rays from the young, spin-powered radio pulsar PSR J2021+3651 using data acquired with the Large Area Telescope (LAT) on the Fermi Gamma-ray Space Telescope (formerly GLAST). The light curve consists of two narrow peaks of similar amplitude separated by 0.468 +/- 0.002 in phase. The first peak lags the maximum of the 2 GHz radio pulse by 0.162 +/- 0.004 +/- 0.01 in phase. The integral gamma-ray photon flux above 100 MeV is (56 +/- 3 +/- 11) x 10^{-8} /cm2/s. The photon spectrum is well-described by an exponentially cut-off power law of the form dF/dE = kE^{-\\Gamma} e^(-E/E_c) where the energy E is expressed in GeV. The photon index is \\Gamma = 1.5 +/- 0.1 +/- 0.1 and the exponential cut-off is E_c = 2.4 +/- 0.3 +/- 0.5 GeV. The first uncertainty is statistical and the second is systematic. The integral photon flux of the bridge is approximately 10% of the pulsed emission, and the upper limit on off-pulse gamma-ray emission from a putative pulsar wind nebula is <10% o...

Abdo, A A

2009-01-01T23:59:59.000Z

314

Phase structure of mass- and spin-imbalanced unitary Fermi gases  

E-Print Network [OSTI]

We study the phase diagram of mass- and spin-imbalanced unitary Fermi gases, in search for the emergence of spatially inhomogeneous phases. To account for fluctuation effects beyond the mean-field approximation, we employ renormalization group techniques. We thus obtain estimates for critical values of the temperature, mass and spin imbalance, above which the system is in the normal phase. In the unpolarized, equal-mass limit, our result for the critical temperature is in accordance with state-of-the-art Monte Carlo calculations. In addition, we estimate the location of regions in the phase diagram where inhomogeneous phases are likely to exist. We show that an intriguing relation exists between the general structure of the many-body phase diagram and the binding energies of the underlying two-body bound-state problem, which further supports our findings. Our results suggest that inhomogeneous condensates form for mass ratios of the spin-down and spin-up fermions greater than three. The extent of the inhomoge...

Roscher, Dietrich; Drut, Joaquín E

2015-01-01T23:59:59.000Z

315

Relativistic dynamics compels a thermalized Fermi gas to a unique intrinsic parity eigenstate  

E-Print Network [OSTI]

Dirac equation describes the dynamics of a relativistic spin-1/2 particle regarding its spatial motion and intrinsic degrees of freedom. Here we adopt the point of view that the spinors describe the state of a massive particle carrying two qubits of information: helicity and intrinsic parity. We show that the density matrix for a gas of free fermions, in thermal equilibrium, correlates helicity and intrinsic parity. Our results introduce the basic elements for discussing the spin-parity correlation for a Fermi gas: (1) at the ultra-relativistic domains, when the temperature is quite high, $T > 10^{10}\\ K$, the fermions have no definite intrinsic parity (50% : 50%), which is maximally correlated with the helicity; (2) at very low temperature, $T \\approx 3 \\ K$, a unique parity dominates (conventionally chosen positive), by $10^{20}$ to $1$, while the helicity goes into a mixed state for spin up and down, and the quantum correlation decoheres. For the anti-fermions we get the opposite behavior. In the framework of quantum information, our result could be considered as a plausible explanation of why we do accept, as a fact (consistent with the experimental observation), that fermions (and anti-fermions), in our present epoch of a cool universe, have a unique intrinsic parity. The framework for constructing spin-parity entangled states is established.

Alex E. Bernardini; Salomon S. Mizrahi

2014-04-21T23:59:59.000Z

316

Fermi Large Area Telescope Observations of the Cygnus Loop Supernova Remnant  

SciTech Connect (OSTI)

We present an analysis of the gamma-ray measurements by the Large Area Telescope (LAT) onboard the Fermi Gamma-ray Space Telescope in the region of the supernova remnant (SNR) Cygnus Loop (G74.0-8.5). We detect significant gamma-ray emission associated with the SNR in the energy band 0.2-100 GeV. The gamma-ray spectrum shows a break in the range 2-3 GeV. The gamma-ray luminosity is {approx} 1 x 10{sup 33} erg s{sup -1} between 1-100 GeV, much lower than those of other GeV-emitting SNRs. The morphology is best represented by a ring shape, with inner/outer radii 0{sup o}.7 {+-} 0{sup o}.1 and 1{sup o}.6 {+-} 0{sup o}.1. Given the association among X-ray rims, H{alpha} filaments and gamma-ray emission, we argue that gamma rays originate in interactions between particles accelerated in the SNR and interstellar gas or radiation fields adjacent to the shock regions. The decay of neutral pions produced in nucleon-nucleon interactions between accelerated hadrons and interstellar gas provides a reasonable explanation for the gamma-ray spectrum.

Katagiri, H.; /Ibaraki U., Mito; Tibaldo, L.; /INFN, Padua /Padua U. /Paris U., VI-VII; Ballet, J.; /Paris U., VI-VII; Giordano, F.; /Bari U. /Bari Polytechnic /INFN, Bari; Grenier, I.A.; /Paris U., VI-VII; Porter, T.A.; /Stanford U., HEPL /KIPAC, Menlo Park /SLAC; Roth, M.; /Washington U., Seattle; Tibolla, O.; /Wurzburg U.; Uchiyama, Y.; /Stanford U., HEPL /KIPAC, Menlo Park /SLAC; Yamazaki, R.; /Sagamihara, Aoyama Gakuin U.

2011-11-08T23:59:59.000Z

317

FERMI-LAT OBSERVATIONS AND A BROADBAND STUDY OF SUPERNOVA REMNANT CTB 109  

SciTech Connect (OSTI)

CTB 109 (G109.1-1.0) is a Galactic supernova remnant (SNR) with a hemispherical shell morphology in X-rays and in the radio band. In this work, we report the detection of {gamma}-ray emission coincident with CTB 109, using 37 months of data from the Large Area Telescope on board the Fermi Gamma-ray Space Telescope. We study the broadband characteristics of the remnant using a model that includes hydrodynamics, efficient cosmic-ray (CR) acceleration, nonthermal emission, and a self-consistent calculation of the X-ray thermal emission. We find that the observations can be successfully fit with two distinct parameter sets, one where the {gamma}-ray emission is produced primarily by leptons accelerated at the SNR forward shock and the other where {gamma}-rays produced by forward shock accelerated CR ions dominate the high-energy emission. Consideration of thermal X-ray emission introduces a novel element to the broadband fitting process, and while it does not rule out either the leptonic or the hadronic scenarios, it constrains the parameter sets required by the model to fit the observations. Moreover, the model that best fits the thermal and nonthermal emission observations is an intermediate case, where both radiation from accelerated electrons and hadrons contribute almost equally to the {gamma}-ray flux observed.

Castro, Daniel [MIT-Kavli Center for Astrophysics and Space Research, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States); Slane, Patrick; Patnaude, Daniel J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Ellison, Donald C. [Physics Department, North Carolina State University, Box 8202, Raleigh, NC 27695 (United States)

2012-09-01T23:59:59.000Z

318

FERMI-LAT AND WMAP OBSERVATIONS OF THE PUPPIS A SUPERNOVA REMNANT  

SciTech Connect (OSTI)

We report the detection of GeV {gamma}-ray emission from the supernova remnant (SNR) Puppis A with the Fermi Gamma-Ray Space Telescope. Puppis A is among the faintest SNRs yet detected at GeV energies, with a luminosity of only 2.7 Multiplication-Sign 10{sup 34} (D/2.2 kpc){sup 2} erg s{sup -1} between 1 and 100 GeV. The {gamma}-ray emission from the remnant is spatially extended, with a morphology matching that of the radio and X-ray emission, and is well described by a simple power law with an index of 2.1. We attempt to model the broadband spectral energy distribution (SED), from radio to {gamma}-rays, using standard nonthermal emission mechanisms. To constrain the relativistic electron population we use 7 years of Wilkinson Microwave Anisotropy Probe data to extend the radio spectrum up to 93 GHz. Both leptonic- and hadronic-dominated models can reproduce the nonthermal SED, requiring a total content of cosmic-ray electrons and protons accelerated in Puppis A of at least W {sub CR} Almost-Equal-To (1-5) Multiplication-Sign 10{sup 49} erg.

Hewitt, J. W. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Grondin, M.-H. [Max-Planck-Institut fuer Kernphysik, D-69029 Heidelberg (Germany); Lemoine-Goumard, M.; Reposeur, T. [Centre d'Etudes Nucleaires de Bordeaux-Gradignan, Universite Bordeaux 1, CNRS/IN2p3, F-33175 Gradignan (France); Ballet, J. [Laboratoire AIM, CEA-IRFU/CNRS/Universite Paris Diderot, Service d'Astrophysique, CEA Saclay, F-91191 Gif sur Yvette (France); Tanaka, T., E-mail: john.w.hewitt@nasa.gov, E-mail: marie-helene.grondin@mpi-hd.mpg.de, E-mail: lemoine@cenbg.in2p3.fr [W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States)

2012-11-10T23:59:59.000Z

319

IDENTIFYING BREAKS AND CURVATURE IN THE FERMI SPECTRA OF BRIGHT FLAT SPECTRUM RADIO QUASARS  

SciTech Connect (OSTI)

Knowing the site of {gamma}-ray emission in active galactic nucleus jets will do much for our understanding of the physics of the source. In particular, if the emission region is close to the black hole then absorption of {gamma}-rays with photons from the broad-line region could become significant. Such absorption is predicted to produce two specific spectral breaks in the {gamma}-ray spectra of Flat Spectrum Radio Quasars (FSRQs). We test this hypothesis using three years of Fermi observations of nine bright FSRQs. A simple power-law fit to the spectrum of each source can be significantly improved by introducing a break, but the break energies are inconsistent with those predicted by the double-absorber model. In some cases the fit can be further improved by a log-parabola. In addition, by dividing the data from each source into two equal epochs we find that the best description of an object's spectrum often varies between a log-parabola and a broken power law.

Harris, J.; Daniel, M. K.; Chadwick, P. M., E-mail: j.d.harris@durham.ac.uk [Department of Physics, Durham University, South Road, Durham DH1 3LE (United Kingdom)

2012-12-10T23:59:59.000Z

320

RADIO DETECTION OF THE FERMI-LAT BLIND SEARCH MILLISECOND PULSAR J1311-3430  

SciTech Connect (OSTI)

We report the detection of radio emission from PSR J1311-3430, the first millisecond pulsar (MSP) discovered in a blind search of Fermi Large Area Telescope (LAT) gamma-ray data. We detected radio pulsations at 2 GHz, visible for <10% of {approx}4.5 hr of observations using the Green Bank Telescope (GBT). Observations at 5 GHz with the GBT and at several lower frequencies with Parkes, Nancay, and the Giant Metrewave Radio Telescope resulted in non-detections. We also report the faint detection of a steep spectrum continuum radio source (0.1 mJy at 5 GHz) in interferometric imaging observations with the Jansky Very Large Array. These detections demonstrate that PSR J1311-3430 is not radio quiet and provide additional evidence that radio-quiet MSPs are rare. The radio dispersion measure of 37.8 pc cm{sup -3} provides a distance estimate of 1.4 kpc for the system, yielding a gamma-ray efficiency of 30%, typical of LAT-detected MSPs. We see apparent excess delay in the radio pulses as the pulsar appears from eclipse and we speculate on possible mechanisms for the non-detections of the pulse at other orbital phases and observing frequencies.

Ray, P. S.; Wood, K. S. [Space Science Division, Naval Research Laboratory, Washington, DC 20375-5352 (United States); Ransom, S. M. [National Radio Astronomy Observatory (NRAO), Charlottesville, VA 22903 (United States); Cheung, C. C. [National Academy of Sciences, Washington, DC 20001 (United States); Giroletti, M. [INAF Istituto di Radioastronomia, I-40129 Bologna (Italy); Cognard, I. [Laboratoire de Physique et Chimie de l'Environnement, LPCE UMR 6115 CNRS, F-45071 Orleans Cedex 02 (France); Camilo, F. [Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States); Bhattacharyya, B. [Inter-University Centre for Astronomy and Astrophysics, Pune 411 007 (India); Roy, J. [National Centre for Radio Astrophysics, Tata Institute of Fundamental Research, Pune 411 007 (India); Romani, R. W.; Kerr, M. [W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States); Ferrara, E. C. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Guillemot, L.; Kramer, M. [Max-Planck-Institut fuer Radioastronomie, Auf dem Huegel 69, D-53121 Bonn (Germany); Johnston, S.; Keith, M. [CSIRO Astronomy and Space Science, Australia Telescope National Facility, Epping NSW 1710 (Australia); Pletsch, H. J. [Max-Planck-Institut fuer Gravitationsphysik, Albert-Einstein-Institut, D-30167 Hannover (Germany); Saz Parkinson, P. M., E-mail: Paul.Ray@nrl.navy.mil [Santa Cruz Institute for Particle Physics, Department of Physics and Department of Astronomy and Astrophysics, University of California at Santa Cruz, Santa Cruz, CA 95064 (United States)

2013-01-20T23:59:59.000Z

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321

Nonsingular Formulation of the Brueckner Approximation for an Infinite Fermi System  

Science Journals Connector (OSTI)

In the approximation neglecting any but single pair correlations, singularities of the reaction matrix render Brueckner's integral for the average energy per particle a singular integral. Several attempts to overcome this difficulty have been unsuccessful. By considering the infinite Fermi system to be a limit of finite systems, it is shown that the correct result merely involves replacing Brueckner's ordinary integral over diagonal reaction matrix elements by a principal value integral. In a finite system the level shift of a Bethe-Goldstone state differs from the diagonal reaction matrix element by a normalization factor which does not approach unity uniformly in the integration variable as the volume becomes infinite. In the neighborhood of a singularity the expression for the two-particle energy shift takes the form cy(y2+cU-1), where y is the unperturbed energy measured from the singularity, c is the square of a matrix element, and U is the quantization volume. Hence as U?? the sum over the energy y indeed approaches a principal value integral. An alternative derivation, employing a modified reaction matrix for which there is no difference between level shift and matrix element, leads to the same result. The general derivations are preceded by a soluble example.The connection of the Brueckner approximation with a phase-shift approximation for low-density systems is discussed. Some corrections to the higher order terms in existing derivations of the "separation method" expansion of the Brueckner reaction matrix are given.

Richard L. Becker

1962-08-15T23:59:59.000Z

322

Nonlocal extension of the dispersive-optical-model to describe data below the Fermi energy  

E-Print Network [OSTI]

Present applications of the dispersive-optical-model analysis are restricted by the use of a local but energy-dependent version of the generalized Hartree-Fock potential. This restriction is lifted by the introduction of a corresponding nonlocal potential without explicit energy dependence. Such a strategy allows for a complete determination of the nucleon propagator below the Fermi energy with access to the expectation value of one-body operators (like the charge density), the one-body density matrix with associated natural orbits, and complete spectral functions for removal strength. The present formulation of the dispersive optical model (DOM) therefore allows the use of elastic electron-scattering data in determining its parameters. Application to ${}^{40}$Ca demonstrates that a fit to the charge radius leads to too much charge near the origin using the conventional assumptions of the functional form of the DOM. A corresponding incomplete description of high-momentum components is identified, suggesting that the DOM formulation must be extended in the future to accommodate such correlations properly. Unlike the local version, the present nonlocal DOM limits the location of the deeply-bound hole states to energies that are consistent with (\\textit{e,e}$^{\\prime}$\\textit{p}) and (\\textit{p,2p}) data.

W. H. Dickhoff; D. Van Neck; S. J. Waldecker; R. J. Charity; L. G. Sobotka

2010-10-07T23:59:59.000Z

323

Catalog of Isolated Emission Episodes in Gamma-ray Bursts from Fermi, Swift and BATSE  

E-Print Network [OSTI]

We report a comprehensive catalog of emission episodes within long gamma-ray bursts (GRBs) that are separated by a quiescent period during which gamma-ray emission falls below the background level. We use a fully automated identification method for an unbiased, large scale and expandable search. We examine a comprehensive sample of long GRBs from the BATSE, Swift and Fermi missions, assembling a total searched set of 2710 GRBs, the largest catalog of isolated emission episodes so far. Our search extends out to [-1000s,750s] around the burst trigger, expanding the covered time interval beyond previous studies and far beyond the nominal durations (T90) of most bursts. We compare our results to previous works by identifying pre-peak emission (or precursors), defined as isolated emission periods prior to the episode with the highest peak luminosity of the burst. We also systematically search for similarly defined periods after the burst's peak emission. We find that the pre-peak and post-peak emission periods are...

Charisi, Maria; Bartos, Imre

2014-01-01T23:59:59.000Z

324

Measuring the bulk Lorentz factors of gamma-ray bursts with Fermi  

E-Print Network [OSTI]

Gamma-ray bursts (GRBs) are powered by ultra-relativistic jets. Usually a minimum value of the Lorentz factor of the relativistic bulk motion is obtained based on the argument that the observed high energy photons ($\\gg {\\rm MeV}$) can escape without suffering from absorption due to pair production. The exact value, rather than a lower limit, of the Lorentz factor can be obtained if the spectral cutoff due to such absorption is detected. With the good spectral coverage of the Large Area Telescope (LAT) on {\\em Fermi}, measurements of such cutoff become possible, and two cases (GRB 090926A and GRB 100724B) have been reported to have high-energy cutoffs or breaks. We systematically search for such high energy spectral cutoffs/breaks from LAT and GBM observations of the prompt emission of GRBs detected since August 2011. Seven more GRBs are found to have cutoff-like spectral feature at energies of $\\sim20-300$ MeV. Assuming that these cutoffs are caused by pair-production absorption within the source, the bulk L...

Tang, Qing-Wen; Wang, Xiang-Yu; Tam, Pak-Hin Thomas

2014-01-01T23:59:59.000Z

325

Reproducing neutrino effects on the matter power spectrum through a degenerate Fermi gas approach  

E-Print Network [OSTI]

Modifications on the predictions about the matter power spectrum based on the hypothesis of a tiny contribution from a degenerate Fermi gas (DFG) test-fluid to some dominant cosmological scenario are investigated. Reporting about the systematic way of accounting for all the cosmological perturbations, through the Boltzmann equation we obtain the analytical results for density fluctuation, $\\delta$, and fluid velocity divergence, $\\theta$, of the DFG. Small contributions to the matter power spectrum are analytically obtained for the radiation-dominated background, through an ultra-relativistic approximation, and for the matter-dominated and $\\Lambda$-dominated eras, through a non-relativistic approximation. The results can be numerically reproduced and compared with those of considering non-relativistic and ultra-relativistic neutrinos into the computation of the matter power spectrum. Lessons concerning the formation of large scale structures of a DFG are depicted, and consequent deviations from standard $\\Lambda$CDM predictions for the matter power spectrum (with and without neutrinos) are quantified.

E. L. D. Perico; Alex E. Bernardini

2011-04-11T23:59:59.000Z

326

Controlled Population of Floquet-Bloch States via Coupling to Bose and Fermi Baths  

E-Print Network [OSTI]

External driving is emerging as a promising tool for exploring new phases in quantum systems. The intrinsically non-equilibrium states that result, however, are challenging to describe and control. We study the steady states of a periodically driven one-dimensional electronic system, including the effects of radiative recombination, electron-phonon interactions, and the coupling to an external fermionic reservoir. Using a kinetic equation for the populations of the Floquet eigenstates, we show that the steady-state distribution can be controlled using the momentum and energy relaxation pathways provided by the coupling to phonon and Fermi reservoirs. In order to utilize the latter, we propose to couple the system and reservoir via an energy filter which suppresses photon-assisted tunneling. Importantly, coupling to these reservoirs yields a steady state resembling a band insulator in the Floquet basis. The system exhibits incompressible behavior, while hosting a small density of excitations. We discuss transport signatures, and describe the regimes where insulating behavior is obtained. Our results give promise for realizing Floquet topological insulators.

Karthik I. Seetharam; Charles-Edouard Bardyn; Netanel H. Lindner; Mark S. Rudner; Gil Refael

2015-02-09T23:59:59.000Z

327

FERMI @ Elettra -- A Seeded Harmonic Cascade FEL for EUV and SoftX-rays  

SciTech Connect (OSTI)

We describe the machine layout and major performance parameters for the FERMI FEL project funded for construction at Sincrotrone Trieste, Italy, within the next five years. The project will be the first user facility based on seeded harmonic cascade FELs, providing controlled, high peak-power pulses. With a high-brightness rf photocathode gun, and using the existing 1.2 GeV S-band linac, the facility will provide tunable output over a range from {approx}100 nm to {approx}10nm, with pulse duration from 40 fs to {approx} 1 ps, peak power GW, and with fully variable output polarization. Initially, two FEL cascades are planned; a single-stage harmonic generation to operate >40 nm, and a two stage cascade operating from {approx}40 nm to {approx}10 nm or shorter wavelength. The output is spatially and temporally coherent, with peak power in the GW range. Lasers provide modulation to the electron beam, as well as driving the photocathode and other systems, and the facility will integrate laser systems with the accelerator infrastructure, including a state-of-the-art optical timing system providing synchronization of rf signals, lasers, and x-ray pulses. Major systems and overall facility layout are described, and key performance parameters summarized.

Bocchetta, C.; Bulfone, D.; Craievich, P.; Danailov, M.B.; D'Auria,G.; DeNinno, G.; Di Mitri, S.; Diviacco, B.; Ferianis, M.; Gomezel, A.; Iazzourene, F.; Karantzoulis, E.; Parmigiani, F.; Penco, G.; Trovo, M.; Corlett, J.; Fawley, W.; Lidia, S.; Penn, G.; Ratti, A.; Staples, J.; Wilcox, R.; Zholents, A.; Graves, W.; Ilday, F.O.; Kaertner,F.; Wang, D.; Zwart, T.; Cornacchia, M.; Emma, P.; Huang, Z.; Wu, J.

2005-09-01T23:59:59.000Z

328

FERMI@Elettra: A Seeded Harmonic Cascade FEL for EUV and Soft X-Rays  

SciTech Connect (OSTI)

We describe the machine layout and major performance parameters for the FERMI FEL project funded for construction at Sincrotrone Trieste, Italy, within the next five years. The project will be the first user facility based on seeded harmonic cascade FEL's, providing controlled, high peak-power pulses. With a high-brightness rf photocathode gun, and using the existing 1.2 GeV S-band linac, the facility will provide tunable output over a range from {approx}100 nm to {approx}10 nm, with pulse duration from 40 fs to {approx} 1ps, peak power {approx}GW, and with fully variable output polarization. Initially, two FEL cascades are planned; a single-stage harmonic generation to operate > 40 nm, and a two-stage cascade operating from {approx}40 nm to {approx}10 nm or shorter wavelength. The output is spatially and temporally coherent, with peak power in the GW range. Lasers provide modulation to the electron beam, as well as driving the photocathode and other systems, and the facility will integrate laser systems with the accelerator infrastructure, including a state-of-the-art optical timing system providing synchronization of rf signals, lasers, and x-ray pulses. Major systems and overall facility layout are described, and key performance parameters summarized.

Bocchetta, C.J.; Bulfone, D.; Craievich, P.; Danailov, M.B.; D'Auria, G.; De Ninno, G.; Di Mitri, S.; Diviacco, B.; Ferianis, M.; Gomezel, A.; Iazzourene, F.; Karantzoulis, E.; Parmigiani, F.; Penco, G.; Trovo, M.; /Sincrotrone Trieste; Corlett, J.; Fawley, W.; Lidia, S.; Penn, G.; Ratti, A.; Staples, J.; /LBL, Berkeley /MIT /SLAC

2005-12-14T23:59:59.000Z

329

Ground-state and dynamical properties of two-dimensional dipolar Fermi liquids  

SciTech Connect (OSTI)

We study the ground-state properties of a two-dimensional spin-polarized fluid of dipolar fermions within the Euler–Lagrange Fermi-hypernetted-chain approximation. Our method is based on the solution of a scattering Schrödinger equation for the “pair amplitude” ?(g(r)), where g(r) is the pair distribution function. A key ingredient in our theory is the effective pair potential, which includes a bosonic term from Jastrow–Feenberg correlations and a fermionic contribution from kinetic energy and exchange, which is tailored to reproduce the Hartree–Fock limit at weak coupling. Very good agreement with recent results based on quantum Monte Carlo simulations is achieved over a wide range of coupling constants up to the liquid-to-crystal quantum phase transition. Using the fluctuation–dissipation theorem and a static approximation for the effective inter-particle interactions, we calculate the dynamical density–density response function, and furthermore demonstrate that an undamped zero-sound mode exists for any value of the interaction strength, down to infinitesimally weak couplings. -- Highlights: •We have studied the ground state properties of a strongly correlated two-dimensional fluid of dipolar fermions. •We have calculated the effective inter-particle interaction and the dynamical density–density response function. •We have shown that an undamped zero sound mode exists at any value of the interaction strength.

Abedinpour, Saeed H., E-mail: abedinpour@iasbs.ac.ir [Department of Physics, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-66731 (Iran, Islamic Republic of); School of Physics, Institute for Research in Fundamental Sciences (IPM), Tehran 19395-5531 (Iran, Islamic Republic of); Asgari, Reza [School of Physics, Institute for Research in Fundamental Sciences (IPM), Tehran 19395-5531 (Iran, Islamic Republic of)] [School of Physics, Institute for Research in Fundamental Sciences (IPM), Tehran 19395-5531 (Iran, Islamic Republic of); Tanatar, B. [Department of Physics, Bilkent University, Bilkent, 06800 Ankara (Turkey)] [Department of Physics, Bilkent University, Bilkent, 06800 Ankara (Turkey); Polini, Marco [NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, I-56126 Pisa (Italy)] [NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, I-56126 Pisa (Italy)

2014-01-15T23:59:59.000Z

330

Experts reveal catalyst-selection methodologies  

SciTech Connect (OSTI)

Refining catalyst selection procedure were discussed in detail at Oil and Gas Journal`s International Catalyst Conference, Feb. 1--2, in Houston. Marathon Oil Co.`s James P. Wick revealed details of Marathon`s program for review and optimization of fluid catalytic cracking (FCC) and hydrotreating catalysts. And renowned FCC expert Del Tolen outlined a step-by-step procedure for choosing an FCC catalyst. The paper describes Marathon`s program and Tolen`s selection process.

NONE

1996-10-14T23:59:59.000Z

331

ALS Reveals New State of Matter  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

ALS Reveals New State of Matter ALS Reveals New State of Matter ALS Reveals New State of Matter Print Wednesday, 13 October 2010 00:00 ALS user groups from Princeton and Stanford have been making waves this past year with several high-profile papers and extensive news coverage of their work on a new state of matter embodied by "topological insulators," materials that conduct electricity only on their surfaces. First identified at the ALS in 2007 by a Princeton team led by M. Zahid Hasan, topological insulators have been the subject of intense interest, based on unusual quantum properties that manifest themselves macroscopically. The discovery of a "second generation" of topological insulators that robustly retain these properties well above room temperature has spurred a rising tide of theoretical proposals for potential applications in nanoscale spintronic devices and fault-tolerant quantum computers. In addition, it's also been suggested that topological insulators may serve as a test bed for studies of never-before-seen particles predicted by high-energy physics.

332

Detailed photoluminescence studies of thin film Cu{sub 2}S for determination of quasi-Fermi level splitting and defect levels  

SciTech Connect (OSTI)

We have studied chalcocite (Cu{sub 2}S) layers prepared by physical vapor deposition with varying deposition parameters by calibrated spectral photoluminescence (PL) and by confocal PL with lateral resolution of ??x?0.9??m. Calibrated PL experiments as a function of temperature T and excitation fluxes were performed to obtain the absolute PL-yield and to calculate the splitting of the quasi-Fermi levels (QFLs) ?=E{sub f,n}?E{sub f,p} at an excitation flux equivalent to the AM 1.5 spectrum and the absorption coefficient ?(??), both in the temperature range of 20?K?T?400?K. The PL-spectra reveal two peaks at E{sub #1}=1.17?eV and E{sub #2}=1.3?eV. The samples show a QFL-splitting of ?>700?meV associated with a pseudo band gap of E{sub g}=1.25?eV. The high-energy peak shows an unexpected temperature behavior, namely, an increase of PL-yield with rising temperature at variance with the behavior of QFL-splitting that decreases with rising T. Our observations indicate that, contrary to common believe, it is not the PL-yield, but rather the QFL-splitting that is the comprehensive indicator of the quality of the excited state in an illuminated semiconductor. A further examination of the lateral variation of opto-electronic properties by confocal PL and the surface contour shows no detectable correlation between Cu{sub 2}S grains/grain boundaries and the PL-yield or QFL-splitting.

Sträter, H., E-mail: hendrik.straeter@uni-oldenburg.de; Brüggemann, R.; Bauer, G. H. [Institute of Physics, Carl von Ossietzky University Oldenburg, 26111 Oldenburg (Germany); Siol, S.; Klein, A.; Jaegermann, W. [Surface Science Division, Institute of Materials Science, Technische Universität Darmstadt, Petersenstraße 32, 64287 Darmstadt (Germany)

2013-12-21T23:59:59.000Z

333

Single-Molecule Dynamics Reveals Cooperative Binding-Folding...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Molecule Dynamics Reveals Cooperative Binding-Folding in Protein Recognition . Single-Molecule Dynamics Reveals Cooperative Binding-Folding in Protein Recognition . Abstract: The...

334

Computer modeling reveals how surprisingly potent hepatitis C...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Hepatitis C computer modeling Computer modeling reveals how surprisingly potent hepatitis C drug works A study reveals how daclatasvir targets one of its proteins and causes the...

335

Research Led by Sandia Reveals Leading-Edge Erosion Significantly...  

Broader source: Energy.gov (indexed) [DOE]

Research Led by Sandia Reveals Leading-Edge Erosion Significantly Reduces Wind Turbine Performance Research Led by Sandia Reveals Leading-Edge Erosion Significantly Reduces Wind...

336

DOE Testing Reveals Samsung Refrigerator Does Not Meet Energy...  

Broader source: Energy.gov (indexed) [DOE]

Testing Reveals Samsung Refrigerator Does Not Meet Energy Star Requirements DOE Testing Reveals Samsung Refrigerator Does Not Meet Energy Star Requirements March 16, 2010 - 4:28pm...

337

High-Resolution Crack Imaging Reveals Degradation Processes in...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Crack Imaging Reveals Degradation Processes in Nuclear Reactor Structural Materials. High-Resolution Crack Imaging Reveals Degradation Processes in Nuclear Reactor Structural...

338

A Revealing Look Inside Passive and Active DPF Regeneration:...  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

A Revealing Look Inside Passive and Active DPF Regeneration: In-Situ Optical Analysis of Ash Formation and Transport A Revealing Look Inside Passive and Active DPF Regeneration:...

339

THE INTERPLANETARY NETWORK SUPPLEMENT TO THE FERMI GBM CATALOG OF COSMIC GAMMA-RAY BURSTS  

SciTech Connect (OSTI)

We present Interplanetary Network (IPN) data for the gamma-ray bursts in the first Fermi Gamma-Ray Burst Monitor (GBM) catalog. Of the 491 bursts in that catalog, covering 2008 July 12 to 2010 July 11, 427 were observed by at least one other instrument in the nine-spacecraft IPN. Of the 427, the localizations of 149 could be improved by arrival time analysis (or {sup t}riangulation{sup )}. For any given burst observed by the GBM and one other distant spacecraft, triangulation gives an annulus of possible arrival directions whose half-width varies between about 0.'4 and 32 Degree-Sign , depending on the intensity, time history, and arrival direction of the burst, as well as the distance between the spacecraft. We find that the IPN localizations intersect the 1{sigma} GBM error circles in only 52% of the cases, if no systematic uncertainty is assumed for the latter. If a 6 Degree-Sign systematic uncertainty is assumed and added in quadrature, the two localization samples agree about 87% of the time, as would be expected. If we then multiply the resulting error radii by a factor of three, the two samples agree in slightly over 98% of the cases, providing a good estimate of the GBM 3{sigma} error radius. The IPN 3{sigma} error boxes have areas between about 1 arcmin{sup 2} and 110 deg{sup 2}, and are, on the average, a factor of 180 smaller than the corresponding GBM localizations. We identify two bursts in the IPN/GBM sample that did not appear in the GBM catalog. In one case, the GBM triggered on a terrestrial gamma flash, and in the other, its origin was given as ''uncertain''. We also discuss the sensitivity and calibration of the IPN.

Hurley, K. [University of California, Berkeley, Space Sciences Laboratory, 7 Gauss Way, Berkeley, CA 94720-7450 (United States); Pal'shin, V. D.; Aptekar, R. L.; Golenetskii, S. V.; Frederiks, D. D.; Mazets, E. P.; Svinkin, D. S. [Ioffe Physical Technical Institute, St. Petersburg 194021 (Russian Federation); Briggs, M. S.; Connaughton, V. [University of Alabama in Huntsville, NSSTC, 320 Sparkman Drive, Huntsville, AL 35805 (United States); Meegan, C. [Universities Space Research Association, NSSTC, 320 Sparkman Drive, Huntsville, AL 35805 (United States); Goldsten, J. [Applied Physics Laboratory, Johns Hopkins University, Laurel, MD 20723 (United States); Boynton, W.; Fellows, C.; Harshman, K. [University of Arizona, Department of Planetary Sciences, Tucson, AZ 85721 (United States); Mitrofanov, I. G.; Golovin, D. V.; Kozyrev, A. S.; Litvak, M. L.; Sanin, A. B. [Space Research Institute, 84/32, Profsoyuznaya, Moscow 117997 (Russian Federation); Rau, A., E-mail: khurley@ssl.berkeley.edu [Max-Planck-Institut fuer extraterrestrische Physik, Giessenbachstrasse, Postfach 1312, D-85748 Garching (Germany); and others

2013-08-15T23:59:59.000Z

340

THE FERMI BUBBLES AS A SCALED-UP VERSION OF SUPERNOVA REMNANTS  

SciTech Connect (OSTI)

In this study, we treat Fermi bubbles as a scaled-up version of supernova remnants (SNRs). The bubbles are created through activities of the super-massive black hole (SMBH) or starbursts at the Galactic center (GC). Cosmic-rays (CRs) are accelerated at the forward shocks of the bubbles like SNRs, which means that we cannot decide whether the bubbles were created by the SMBH or starbursts from the radiation from the CRs. We follow the evolution of CR distribution by solving a diffusion-advection equation, considering the reduction of the diffusion coefficient by CR streaming. In this model, gamma rays are created through hadronic interaction between CR protons and the gas in the Galactic halo. In the GeV band, we can well reproduce the observed flat distribution of gamma-ray surface brightness because some amount of gas is left behind the shock. The edge of the bubbles is fairly sharp owing to the high gas density behind the shock and the reduction of the diffusion coefficient there. The latter also contributes the hard gamma-ray spectrum of the bubbles. We find that the CR acceleration at the shock began when the bubbles were small, and the time scale of the energy injection at the GC was much smaller than the age of the bubbles. We predict that if CRs are accelerated to the TeV regime, the apparent bubble size should be larger in the TeV band, which could be used to discriminate our hadronic model from other leptonic models. We also present neutrino fluxes.

Fujita, Yutaka [Department of Earth and Space Science, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043 (Japan)] [Department of Earth and Space Science, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043 (Japan); Ohira, Yutaka; Yamazaki, Ryo, E-mail: fujita@vega.ess.sci.osaka-u.ac.jp [Department of Physics and Mathematics, Aoyama Gakuin University, Fuchinobe, Chuou-ku, Sagamihara 252-5258 (Japan)] [Department of Physics and Mathematics, Aoyama Gakuin University, Fuchinobe, Chuou-ku, Sagamihara 252-5258 (Japan)

2013-09-20T23:59:59.000Z

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341

IceCube sensitivity for neutrino flux from Fermi blazars in quiescent states  

Science Journals Connector (OSTI)

We investigate the IceCube detection potential of very high energy neutrinos from blazars, for different classes of hadronic models, taking into account the limits imposed on the neutrino flux by the recent Fermi telescope observations. Assuming the observed ?-ray emission is produced by the decay of neutral pions from proton-proton interactions, the measurement of the time-averaged spectral characteristics of blazars in the GeV energy band imposes upper limits on the time-averaged neutrino flux. Comparing these upper limits to the 5? discovery threshold of IceCube for different neutrino spectra and different source locations in the sky, we find that several BL Lacs with hard spectra in the GeV band are within the detection potential of IceCube. If the ?-ray emission is dominated by the neutral pion decay flux, none of the flat-spectrum radio quasars are detectable with IceCube. If the primary high energy proton spectrum is very hard and/or neutrinos are produced in proton photon, rather than proton-proton reactions, the upper limit on the neutrino flux imposed by the measured ?-ray spectra is relaxed and gamma-ray observations impose only lower bounds on the neutrino flux. We investigate whether these lower bounds guarantee the detection of blazars with very hard neutrino spectra (spectral index ???1), expected in the latter type model. We show that all the hadronic models of activity of blazars are falsifiable with IceCube. Furthermore, we show that models with ?-ray emission produced by the decay of neutral pions from proton-proton interactions can be readily distinguished from the models based on proton-gamma interactions and/or models predicting very hard high energy proton spectra via a study of the distribution of spectral indices of ?-ray spectra of sources detected with IceCube.

A. Neronov and M. Ribordy

2009-10-21T23:59:59.000Z

342

Protein Vivisection Reveals Elusive Intermediates in Folding  

SciTech Connect (OSTI)

Although most folding intermediates escape detection, their characterization is crucial to the elucidation of folding mechanisms. Here, we outline a powerful strategy to populate partially unfolded intermediates: A buried aliphatic residue is substituted with a charged residue (e.g., Leu {yields} Glu{sup -}) to destabilize and unfold a specific region of the protein. We applied this strategy to ubiquitin, reversibly trapping a folding intermediate in which the {beta}5-strand is unfolded. The intermediate refolds to a native-like structure upon charge neutralization under mildly acidic conditions. Characterization of the trapped intermediate using NMR and hydrogen exchange methods identifies a second folding intermediate and reveals the order and free energies of the two major folding events on the native side of the rate-limiting step. This general strategy may be combined with other methods and have broad applications in the study of protein folding and other reactions that require trapping of high-energy states.

Zheng, Zhongzhou; Sosnick, Tobin R. (UC)

2010-05-25T23:59:59.000Z

343

Fermi National Accelerator Laboratory / Kirk and Pine Street / P.O. Box 500 / Batavia, IL 60510 / 630.840.3000 / www.fnal.gov / fermilab@fnal.gov Managed by Fermi Research Alliance, LLC for the U.S. Department of Energy Office of Science  

E-Print Network [OSTI]

/ 630.840.3000 / www.fnal.gov / fermilab@fnal.gov Managed by Fermi Research Alliance, LLC for the U responsibility to notify Fermilab within 30 days if my dependent no longer meets the requirements as outlined

Quigg, Chris

344

The Search for High Energy Extended Emission by Fermi-LAT from Swift-Localized Gamma-Ray Bursts  

SciTech Connect (OSTI)

The brighter Fermi-LAT bursts have exhibited emission at energies >0.1 GeV that persists as late as {approx}2 ks after the prompt phase has nominally ended. This so-called 'extended emission' could arise from continued activity of the prompt burst mechanism or it could be the start of a high energy afterglow component. The high energy extended emission seen by the LAT has typically followed a t{sup -}{gamma} power-law temporal decay where {gamma} {approx} 1.2-1.7 and has shown no strong indication of spectral evolution. In contrast, the prompt burst emission generally displays strong spectral variability and more complex temporal changes in the LAT band. This differing behavior suggests that the extended emission likely corresponds to an early afterglow phase produced by an external shock. In this study, we look for evidence of high energy extended emission from 145 Swift-localized GRBs that have occurred since the launch of Fermi. A majority of these bursts were either outside of the LAT field-of-view or were otherwise not detected by the LAT during the prompt phase. However, because of the scanning operation of the Fermi satellite, the long-lived extended emission of these bursts may be detectable in the LAT data on the {approx}few ks time scale. We will look for emission from individual bursts and will perform a stacking analysis in order to set bounds on this emission for the sample as a whole. The detection of such emission would have implications for afterglow models and for the overall energy budget of GRBs.

Chiang, J.; /Stanford U., HEPL /SLAC; Racusin, J.L.; /NASA, Goddard

2012-05-01T23:59:59.000Z

345

FERMI/LAT OBSERVATIONS OF SWIFT/BAT SEYFERT GALAXIES: ON THE CONTRIBUTION OF RADIO-QUIET ACTIVE GALACTIC NUCLEI TO THE EXTRAGALACTIC {gamma}-RAY BACKGROUND  

SciTech Connect (OSTI)

We present the analysis of 2.1 years of Fermi Large Area Telescope (LAT) data on 491 Seyfert galaxies detected by the Swift Burst Alert Telescope (BAT) survey. Only the two nearest objects, NGC 1068 and NGC 4945, which were identified in the Fermi first year catalog, are detected. Using Swift/BAT and radio 20 cm fluxes, we define a new radio-loudness parameter R{sub X,BAT} where radio-loud objects have log R{sub X,BAT} > -4.7. Based on this parameter, only radio-loud sources are detected by Fermi/LAT. An upper limit to the flux of the undetected sources is derived to be {approx}2 Multiplication-Sign 10{sup -11} photons cm{sup -2} s{sup -1}, approximately seven times lower than the observed flux of NGC 1068. Assuming a median redshift of 0.031, this implies an upper limit to the {gamma}-ray (1-100 GeV) luminosity of {approx}< 3 Multiplication-Sign 10{sup 41} erg s{sup -1}. In addition, we identified 120 new Fermi/LAT sources near the Swift/BAT Seyfert galaxies with significant Fermi/LAT detections. A majority of these objects do not have Swift/BAT counterparts, but their possible optical counterparts include blazars, flat-spectrum radio quasars, and quasars.

Teng, Stacy H.; Mushotzky, Richard F.; Reynolds, Christopher S. [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Sambruna, Rita M. [Department of Physics and Astronomy, George Mason University, Fairfax, VA 22030 (United States); Davis, David S., E-mail: stacyt@astro.umd.edu [CRESST and X-ray Astrophysics Laboratory, NASA/GSFC, Greenbelt, MD 20771 (United States)

2011-12-01T23:59:59.000Z

346

Fermi-level shifts in graphene transistors with dual-cut channels scraped by atomic force microscope tips  

SciTech Connect (OSTI)

We investigate the electronic properties of p-type graphene transistors on silicon dioxide with dual-cut channels that were scraped using atomic force microscope tips. In these devices, the current is forced to squeeze into the path between the two cuts rather than flow directly through the graphene sheet. We observe that the gate voltages with minimum current shift toward zero bias as the sizes of the dual-cut regions increase. These phenomena suggest that the Fermi levels in the dual-cut regions are shifted toward the Dirac points after the mechanical scraping process.

Lin, Meng-Yu [Institute of Electronics, National Taiwan University, Taipei 10617, Taiwan (China); Research Center for Applied Sciences, Academia Sinica, Taipei 11529, Taiwan (China); Chen, Yen-Hao [Department of Photonics, National Chiao Tung University, Hsinchu 30010, Taiwan (China); Su, Chen-Fung [College of Photonics, National Chiao Tung University, Tainan 71150, Taiwan (China); Chang, Shu-Wei [Research Center for Applied Sciences, Academia Sinica, Taipei 11529, Taiwan (China); Department of Photonics, National Chiao Tung University, Hsinchu 30010, Taiwan (China); Lee, Si-Chen [Institute of Electronics, National Taiwan University, Taipei 10617, Taiwan (China); Lin, Shih-Yen, E-mail: shihyen@gate.sinica.edu.tw [Institute of Electronics, National Taiwan University, Taipei 10617, Taiwan (China); Research Center for Applied Sciences, Academia Sinica, Taipei 11529, Taiwan (China); Department of Photonics, National Chiao Tung University, Hsinchu 30010, Taiwan (China)

2014-01-13T23:59:59.000Z

347

Doping dependence of Fermi surface in high-Tc cuprates studied by model Hartree-Fock calculations  

Science Journals Connector (OSTI)

We have investigated doping dependence of Fermi surface, band dispersion, and magnetic structure in high-Tc cuprates by using Hartree-Fock calculation on a Cu 3d–O 2p tight-binding model. In the slightly electron-doped regime, electron pockets emerge around (?,0), which agrees with the photoemission study of Nd2-xCexCuO4. In the slightly hole-doped regime, hole pockets emerge around (?/2,?/2), which might explain the recent photoemission result of Ca2-xNaxCuO2Cl2.

D. Asakura and T. Mizokawa

2003-09-23T23:59:59.000Z

348

Fermi surface evolution and collapse of the Mott pseudogap in Nd2-xCexCuO4±?  

Science Journals Connector (OSTI)

Fermi surface (FS) maps and spectral intensities obtained recently in Nd2-xCexCuO4±? via high resolution ARPES measurements are analyzed using mean-field Hartree Fock and self-consistent renormalization computations within the framework of the one-band t-t?-t?-U Hubbard model Hamiltonian. We show that the remarkable observed crossover of the FS from small to large sheets reflects a reduction in the value of the effective Hubbard U with increasing electron doping and the collapse of the correlation induced Mott pseudogap just above optimal doping.

C. Kusko; R. S. Markiewicz; M. Lindroos; A. Bansil

2002-10-31T23:59:59.000Z

349

Transition of fermionic spectra and monopole oscillations under phase separation in the atomic Bose-Fermi mixture  

Science Journals Connector (OSTI)

We study the dynamical behavior of a Bose-Fermi mixture of trapped atomic gases which exhibits phase separation for a sufficiently strong repulsive interparticle interaction. For a dominantly bosonic mixture, the fermion density distribution and the associated single-particle spectra undergo a rapid change around the transition to the separated phase. Monopole strength distribution is studied in the random-phase approximation. The average energy calculated from the fermionic monopole strength shows a sharp minimum close to the transition point. The dynamical origin of the fermion single particle and collective properties is studied within a simple approximation.

T. Sogo; T. Suzuki; H. Yabu

2003-12-15T23:59:59.000Z

350

Comparison of 1D and 2D CSR Models with Application to the FERMI@ELETTRA Bunch Compressors  

SciTech Connect (OSTI)

We compare our 2D mean field (Vlasov-Maxwell) treatment of coherent synchrotron radiation (CSR) effects with 1D approximations of the CSR force which are commonly implemented in CSR codes. In our model we track particles in 4D phase space and calculate 2D forces [1]. The major cost in our calculation is the computation of the 2D force. To speed up the computation and improve 1D models we also investigate approximations to our exact 2D force. As an application, we present numerical results for the Fermi{at}Elettra first bunch compressor with the configuration described in [1].

Bassi, G.; Ellison, J.A.; Heinemann, K.

2011-03-28T23:59:59.000Z

351

The Arithmetic of Entire Functions under Composition  

E-Print Network [OSTI]

at the Hong Kong University of Science and Technology, which is thanked for its support and hospitality. ...... So we have handled every case except the one where the above proce- ... Apply the Y-process to F=(g:&1 , f:) to produce G=g: with g:.

Eremenko, A., et al.

1996-12-26T23:59:59.000Z

352

"EntirelyBlackVerse from Him Would  

E-Print Network [OSTI]

AND HOWELLS 495 ington Cable, Henry James, Sarah Orne Jewett,Joel Chandler Harris, and MarkDunbar and His Song (New York:Dodd, Mead, and Co., 1947), p. 144. William Dean Howells ascended the professional

Goldberg, Bennett

353

Pulsed Gamma-Rays From PSR J2021 3651 with the Fermi Large Area Telescope  

SciTech Connect (OSTI)

We report the detection of pulsed gamma-rays from the young, spin-powered radio pulsar PSR J2021+3651 using data acquired with the Large Area Telescope (LAT) on the Fermi Gamma-ray Space Telescope (formerly GLAST). The light curve consists of two narrow peaks of similar amplitude separated by 0.468 {+-} 0.002 in phase. The first peak lags the maximum of the 2 GHz radio pulse by 0.162 {+-} 0.004 {+-} 0.01 in phase. The integral gamma-ray photon flux above 100 MeV is (56 {+-} 3 {+-} 11) x 10{sup -8} cm{sup -2} s{sup -1}. The photon spectrum is well-described by an exponentially cut-off power law of the form dF/dE = kE{sup -{Gamma}}e{sup (-E/E{sub c})} where the energy E is expressed in GeV. The photon index is {Gamma} = 1.5 {+-} 0.1 {+-} 0.1 and the exponential cut-off is E{sub c} = 2.4 {+-} 0.3 {+-} 0.5 GeV. The first uncertainty is statistical and the second is systematic. The integral photon flux of the bridge is approximately 10% of the pulsed emission, and the upper limit on off-pulse gamma-ray emission from a putative pulsar wind nebula is < 10% of the pulsed emission at the 95% confidence level. Radio polarization measurements yield a rotation measure of RM = 524 {+-} 4 rad m{sup -2} but a poorly constrained magnetic geometry. Re-analysis of Chandra data enhanced the significance of the weak X-ray pulsations, and the first peak is roughly phase-aligned with the first gamma-ray peak. We discuss the emission region and beaming geometry based on the shape and spectrum of the gamma-ray light curve combined with radio and X-ray measurements, and the implications for the pulsar distance. Gamma-ray emission from the polar cap region seems unlikely for this pulsar.

Abdo, Aous A.; /Naval Research Lab, Wash., D.C.; Ackermann, M.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Ajello, Marco; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Atwood, William B.; /UC, Santa Cruz; Baldini, L.; /INFN, Pisa; Ballet, J.; /DAPNIA, Saclay; Barbiellini, Guido; /INFN, Trieste /Trieste U.; Bastieri, Denis; /INFN, Padua /Padua U.; Battelino, Milan; /Royal Inst. Tech., Stockholm; Baughman, B.M.; /Ohio State U.; Bechtol, K.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bellazzini, Ronaldo; /INFN, Pisa; Berenji, Bijan; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bloom, Elliott D.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bogaert, G.; /Ecole Polytechnique; Borgland, Anders W.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bregeon, J.; /INFN, Pisa; Brez, A.; /INFN, Pisa; Brigida, M.; /Bari U. /INFN, Bari; Bruel, P.; /Ecole Polytechnique; Burnett, Thompson H.; /Washington U., Seattle /Bari U. /INFN, Bari /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Columbia U. /IASF, Milan /IASF, Milan /DAPNIA, Saclay /INFN, Perugia /Perugia U. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /George Mason U. /Naval Research Lab, Wash., D.C. /IASF, Milan /IASF, Milan /NASA, Goddard /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /INFN, Perugia /Perugia U. /LPCE, Orleans /Montpellier U. /Sonoma State U. /Royal Inst. Tech., Stockholm /Stockholm U. /ASI, Rome /NRAO, Charlottesville /Naval Research Lab, Wash., D.C. /INFN, Trieste /Pavia U. /Bari U. /INFN, Bari /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /UC, Santa Cruz /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /CENBG, Gradignan /CENBG, Gradignan /Manchester U. /Montpellier U. /Bari U. /INFN, Bari; /more authors..

2011-11-30T23:59:59.000Z

354

Fermi Large Area Telescope Observations of the Supernova Remnant G8.7-0.1  

SciTech Connect (OSTI)

We present a detailed analysis of the GeV gamma-ray emission toward the supernova remnant (SNR) G8.7-0.1 with the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope. An investigation of the relationship between G8.7-0.1 and the TeV unidentified source HESS J1804-216 provides us with an important clue on diffusion process of cosmic rays if particle acceleration operates in the SNR. The GeV gamma-ray emission is extended with most of the emission in positional coincidence with the SNR G8.7-0.1 and a lesser part located outside the western boundary of G8.7-0.1. The region of the gamma-ray emission overlaps spatially connected molecular clouds, implying a physical connection for the gamma-ray structure. The total gamma-ray spectrum measured with LAT from 200 MeV-100 GeV can be described by a broken power-law function with a break of 2.4 {+-} 0.6 (stat) {+-} 1.2 (sys) GeV, and photon indices of 2.10 {+-} 0.06 (stat) {+-} 0.10 (sys) below the break and 2.70 {+-} 0.12 (stat) {+-} 0.14 (sys) above the break. Given the spatial association among the gamma rays, the radio emission of G8.7-0.1, and the molecular clouds, the decay of p0s produced by particles accelerated in the SNR and hitting the molecular clouds naturally explains the GeV gamma-ray spectrum. We also find that the GeV morphology is not well represented by the TeV emission from HESS J1804-216 and that the spectrum in the GeV band is not consistent with the extrapolation of the TeV gamma-ray spectrum. The spectral index of the TeV emission is consistent with the particle spectral index predicted by a theory that assumes energy-dependent diffusion of particles accelerated in an SNR. We discuss the possibility that the TeV spectrum originates from the interaction of particles accelerated in G8.7-0.1 with molecular clouds, and we constrain the diffusion coefficient of the particles.

Ajello, M.; Allafort, A.; /Stanford U., HEPL /KIPAC, Menlo Park /SLAC; Baldini, L.; /INFN, Pisa; Ballet, J.; /AIM, Saclay; Barbiellini, G.; /INFN, Trieste /Trieste U.; Bastieri, D.; /INFN, Padua /Padua U.; Bechtol, K.; /Stanford U., HEPL /KIPAC, Menlo Park /SLAC; Bellazzini, R.; /INFN, Pisa; Berenji, B.; Blandford, R.D.; Bloom, E.D.; /Stanford U., HEPL /KIPAC, Menlo Park /SLAC; Bonamente, E.; /INFN, Perugia /Perugia U.; Borgland, A.W.; /Stanford U., HEPL /KIPAC, Menlo Park /SLAC; Bregeon, J.; /INFN, Pisa; Brigida, M.; /Bari Polytechnic /INFN, Bari; Bruel, P.; /Ecole Polytechnique; Buehler, R.; /Stanford U., HEPL /KIPAC, Menlo Park /SLAC; Buson, S.; /INFN, Padua /Padua U.; Caliandro, G.A.; /CSIC, Catalunya; Cameron, R.A.; /Stanford U., HEPL /KIPAC, Menlo Park /SLAC; Caraveo, P.A.; /IASF, Milan /AIM, Saclay /INFN, Perugia /Perugia U. /Stanford U., HEPL /KIPAC, Menlo Park /SLAC /Unlisted, US /Naval Research Lab, Wash., D.C. /Perugia U. /ASDC, Frascati /Stanford U., HEPL /KIPAC, Menlo Park /SLAC /Montpellier U. /ASDC, Frascati /Udine U. /INFN, Trieste /Bari Polytechnic /INFN, Bari /Naval Research Lab, Wash., D.C. /Stanford U., HEPL /KIPAC, Menlo Park /SLAC /Bari Polytechnic /INFN, Bari /Ecole Polytechnique /NASA, Goddard /Stanford U., HEPL /KIPAC, Menlo Park /SLAC /Udine U. /INFN, Trieste /Trieste Observ. /Hiroshima U. /Nagoya U. /Bari Polytechnic /INFN, Bari /INFN, Bari /ASDC, Frascati /INFN, Perugia /Perugia U. /Bari Polytechnic /INFN, Bari /ASDC, Frascati /Bari Polytechnic /INFN, Bari /Bologna Observ. /Stanford U., HEPL /KIPAC, Menlo Park /SLAC /Naval Research Lab, Wash., D.C. /Alabama U., Huntsville /CSIC, Catalunya /Hiroshima U. /NASA, Goddard /Hiroshima U.; /more authors..

2012-09-14T23:59:59.000Z

355

Fermi-LAT gamma-ray anisotropy and intensity explained by unresolved Radio-Loud Active Galactic Nuclei  

E-Print Network [OSTI]

Radio-loud active galactic nuclei (AGN) are expected to contribute substantially to both the intensity and anisotropy of the isotropic gamma-ray background (IGRB). In turn, the measured properties of the IGRB can be used to constrain the characteristics of proposed contributing source classes. We consider individual subclasses of radio-loud AGN, including low-, intermediate-, and high-synchrotron-peaked BL Lacertae objects, flat-spectrum radio quasars, and misaligned AGN. Using updated models of the gamma-ray luminosity functions of these populations, we evaluate the energy-dependent contribution of each source class to the intensity and anisotropy of the IGRB. We find that collectively radio-loud AGN can account for the entirety of the IGRB intensity and anisotropy as measured by the Fermi Large Area Telescope (LAT). Misaligned AGN provide the bulk of the measured intensity but a negligible contribution to the anisotropy, while high-synchrotron-peaked BL Lacertae objects provide the dominant contribution to the anisotropy. In anticipation of upcoming measurements with the Fermi-LAT and the forthcoming Cherenkov Telescope Array, we predict the anisotropy in the broader energy range that will be accessible to future observations.

Mattia Di Mauro; Alessandro Cuoco; Fiorenza Donato; Jennifer M. Siegal-Gaskins

2014-07-11T23:59:59.000Z

356

{gamma}-RAY LUMINOSITY FUNCTION AND THE CONTRIBUTION TO EXTRAGALACTIC {gamma}-RAY BACKGROUND FOR FERMI-DETECTED BLAZARS  

SciTech Connect (OSTI)

We study {gamma}-ray luminosity functions (GLFs) and the contribution to the extragalactic diffuse {gamma}-rays for blazars. After using a clean blazar sample in which 485 blazars are observed at both the 8.4 GHz and {approx} GeV bands, we investigate the radio/{gamma}-ray luminosity correlation and find out that a strong correlation exists between the radio and {gamma}-ray luminosities using the partial correlation analysis method. Based on such a correlation, we obtain the GLF, while also considering the GLF based on studies of the X-ray luminosity function of active galactic nuclei and the GLF of the EGRET blazars. K-S tests indicate that these three kinds of GLFs are consistent with the observed data of our sample in a reasonable parameter range. Using these GLFs, we further investigate the blazar contribution to the extragalactic diffuse {gamma}-ray background (EGRB). Our results show that (1) the contribution of blazars are {approx}21.3% {+-} 2.7%, {approx}12.9% {+-} 1.7%, and {approx}37.9% {+-} 4.8% of unresolved Fermi EGRB flux for the three GLFs and (2) the contribution of flat-spectrum radio quasars are {approx}11.2% {+-} 1.6%, {approx}6.9% {+-} 1.0%, and {approx}9.0% {+-} 1.2% of unresolved Fermi EGRB flux for the three GLFs.

Zeng, H. D.; Yan, D. H.; Sun, Y. Q.; Zhang, L., E-mail: lizhang@ynu.edu.cn [Department of Physics, Yunnan University, Kunming (China)

2012-04-20T23:59:59.000Z

357

REVISITING THE LONG/SOFT-SHORT/HARD CLASSIFICATION OF GAMMA-RAY BURSTS IN THE FERMI ERA  

SciTech Connect (OSTI)

We perform a statistical analysis of the temporal and spectral properties of the latest Fermi gamma-ray bursts (GRBs) to revisit the classification of GRBs. We find that the bimodalities of duration and the energy ratio (E{sub peak}/Fluence) and the anti-correlation between spectral hardness (hardness ratio (HR), peak energy, and spectral index) and duration (T{sub 90}) support the long/soft-short/hard classification scheme for Fermi GRBs. The HR-T{sub 90} anti-correlation strongly depends on the spectral shape of GRBs and energy bands, and the bursts with the curved spectra in the typical BATSE energy bands show a tighter anti-correlation than those with the power-law spectra in the typical BAT energy bands. This might explain why the HR-T{sub 90} correlation is not evident for those GRB samples detected by instruments like Swift with a narrower/softer energy bandpass. We also analyze the intrinsic energy correlation for the GRBs with measured redshifts and well-defined peak energies. The current sample suggests E{sub p,rest} = 2455 Multiplication-Sign (E{sub iso}/10{sup 52}){sup 0.59} for short GRBs, significantly different from that for long GRBs. However, both the long and short GRBs comply with the same E{sub p,rest}-L{sub iso} correlation.

Zhang Fuwen; Yan Jingzhi; Wei Daming [Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China); Shao Lang, E-mail: fwzhang@pmo.ac.cn [Department of Physics, Hebei Normal University, Shijiazhuang 050016 (China)

2012-05-10T23:59:59.000Z

358

Gamma-ray flaring activity from the gravitationally lensed blazar PKS 1830-211 observed by Fermi LAT  

E-Print Network [OSTI]

The Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope routinely detects the highly dust-absorbed, reddened, and MeV-peaked flat spectrum radio quasar PKS 1830-211 (z=2.507). Its apparent isotropic gamma-ray luminosity (E>100 MeV) averaged over $\\sim$ 3 years of observations and peaking on 2010 October 14/15 at 2.9 X 10^{50} erg s^{-1}, makes it among the brightest high-redshift Fermi blazars. No published model with a single lens can account for all of the observed characteristics of this complex system. Based on radio observations, one expects time delayed variability to follow about 25 days after a primary flare, with flux about a factor 1.5 less. Two large gamma-ray flares of PKS 1830-211 have been detected by the LAT in the considered period and no substantial evidence for such a delayed activity was found. This allows us to place a lower limit of about 6 on the gamma rays flux ratio between the two lensed images. Swift XRT observations from a dedicated Target of Opportunity program ...

Abdo, A A; Ajello, M; Allafort, A; Amin, M A; Baldini, L; Barbiellini, G; Bastieri, D; Bechtol, K; Bellazzini, R; Blandford, R D; Bonamente, E; Borgland, A W; Bregeon, J; Brigida, M; Buehler, R; Bulmash, D; Buson, S; Caliandro, G A; Cameron, R A; Caraveo, P A; Cavazzuti, E; Cecchi, C; Charles, E; Cheung, C C; Chiang, J; Chiaro, G; Ciprini, S; Claus, R; Cohen-Tanugi, J; Conrad, J; Corbet, R H D; Cutini, S; D'Ammando, F; de Angelis, A; de Palma, F; Dermer, C D; Drell, P S; Drlica-Wagner, A; Favuzzi, C; Finke, J; Focke, W B; Fukazawa, Y; Fusco, P; Gargano, F; Gasparrini, D; Gehrels, N; Giglietto, N; Giordano, F; Giroletti, M; Glanzman, T; Grenier, I A; Grove, J E; Guiriec, S; Hadasch, D; Hayashida, M; Hays, E; Hughes, R E; Inoue, Y; Jackson, M S; Jogler, T; Jòhannesson, G; Johnson, A S; Kamae, T; Knödlseder, J; Kuss, M; Lande, J; Larsson, S; Latronico, L; Longo, F; Loparco, F; Lott, B; Lovellette, M N; Lubrano, P; Madejski, G M; Mazziotta, M N; Mehault, J; Michelson, P F; Mizuno, T; Monzani, M E; Morselli, A; Moskalenko, I V; Murgia, S; Nemmen, R; Nuss, E; Ohno, M; Ohsugi, T; Paneque, D; Perkins, J S; Pesce-Rollins, M; Piron, F; Pivato, G; Porter, T A; Rainò, S; Rando, R; Razzano, M; Reimer, A; Reimer, O; Reyes, L C; Ritz, S; Romoli, C; Roth, M; Parkinson, P M Saz; Sgrò, C; Siskind, E J; Spandre, G; Spinelli, P; Takahashi, H; Takeuchi, Y; Tanaka, T; Thayer, J G; Thayer, J B; Thompson, D J; Tibaldo, L; Tinivella, M; Torres, D F; Tosti, G; Troja, E; Tronconi, V; Usher, T L; Vandenbroucke, J; Vasileiou, V; Vianello, G; Vitale, V; Waite, A P; Werner, M; Winer, B L; Wood, K S

2014-01-01T23:59:59.000Z

359

Constraints on Lorentz invariance violation from Fermi-Large Area Telescope observations of gamma-ray bursts  

Science Journals Connector (OSTI)

We analyze the MeV/GeV emission from four bright gamma-ray bursts (GRBs) observed by the Fermi Large Area Telescope to produce robust, stringent constraints on a dependence of the speed of light in vacuo on the photon energy (vacuum dispersion), a form of Lorentz invariance violation (LIV) allowed by some quantum gravity (QG) theories. First, we use three different and complementary techniques to constrain the total degree of dispersion observed in the data. Additionally, using a maximally conservative set of assumptions on possible source-intrinsic, spectral-evolution effects, we constrain any vacuum dispersion solely attributed to LIV. We then derive limits on the QG energy scale (the energy scale where LIV-inducing QG effects become strong, EQG) and the coefficients of the Standard Model Extension. For the subluminal case (where high-energy photons propagate more slowly than lower-energy photons) and without taking into account any source-intrinsic dispersion, our most stringent limits (at 95% C.L.) are obtained from GRB 090510 and are EQG,1>7.6 times the Planck energy (EPl) and EQG,2>1.3×1011??GeV for linear and quadratic leading-order LIV-induced vacuum dispersion, respectively. These limits improve the latest constraints by Fermi and H.E.S.S. by a factor of ?2. Our results disfavor any class of models requiring EQG,1?EPl.

V. Vasileiou; A. Jacholkowska; F. Piron; J. Bolmont; C. Couturier; J. Granot; F. W. Stecker; J. Cohen-Tanugi; F. Longo

2013-06-04T23:59:59.000Z

360

Limits on Dark Matter Annihilation Signals from the Fermi LAT 4-year Measurement of the Isotropic Gamma-Ray Background  

E-Print Network [OSTI]

We search for evidence of dark matter (DM) annihilation in the isotropic gamma-ray background (IGRB) measured with 50 months of Fermi Large Area Telescope (LAT) observations. An improved theoretical description of the cosmological DM annihilation signal, based on two complementary techniques and assuming generic weakly interacting massive particle (WIMP) properties, renders more precise predictions compared to previous work. More specifically, we estimate the cosmologically-induced gamma-ray intensity to have an uncertainty of a factor ~20 in canonical setups. We consistently include both the Galactic and extragalactic signals under the same theoretical framework, and study the impact of the former on the IGRB spectrum derivation. We find no evidence for a DM signal and we set limits on the DM-induced isotropic gamma-ray signal. Our limits are competitive for DM particle masses up to tens of TeV and, indeed, are the strongest limits derived from Fermi LAT data at TeV energies. This is possible thanks to the n...

Ackermann, M; Albert, A; Baldini, L; Barbiellini, G; Bastieri, D; Bechtol, K; Bellazzini, R; Bissaldi, E; Bloom, E D; Bonino, R; Bregeon, J; Bruel, P; Buehler, R; Buson, S; Caliandro, G A; Cameron, R A; Caragiulo, M; Caraveo, P A; Cecchi, C; Charles, E; Chekhtman, A; Chiang, J; Chiaro, G; Ciprini, S; Claus, R; Cohen-Tanugi, J; Conrad, J; Cuoco, A; Cutini, S; D'Ammando, F; de Angelis, A; de Palma, F; Dermer, C D; Digel, S W; Drell, P S; Drlica-Wagner, A; Favuzzi, C; Ferrara, E C; Franckowiak, A; Fukazawa, Y; Funk, S; Fusco, P; Gargano, F; Gasparrini, D; Giglietto, N; Giordano, F; Giroletti, M; Godfrey, G; Guiriec, S; Gustafsson, M; Hewitt, J W; Hou, X; Kamae, T; Kuss, M; Larsson, S; Latronico, L; Longo, F; Loparco, F; Lovellette, M N; Lubrano, P; Malyshev, D; Massaro, F; Mayer, M; Mazziotta, M N; Michelson, P F; Mitthumsiri, W; Mizuno, T; Monzani, M E; Morselli, A; Moskalenko, I V; Murgia, S; Negro, M; Nemmen, R; Nuss, E; Ohsugi, T; Orienti, M; Orlando, E; Ormes, J F; Paneque, D; Perkins, J S; Pesce-Rollins, M; Piron, F; Pivato, G; Raino, S; Rando, R; Razzano, M; Reimer, A; Reimer, O; Sanchez-Conde, M; Schulz, A; Sgro, C; Siskind, E J; Spandre, G; Spinelli, P; Strong, A W; Suson, D J; Tajima, H; Takahashi, H; Thayer, J G; Thayer, J B; Tibaldo, L; Tinivella, M; Torres, D F; Troja, E; Uchiyama, Y; Vianello, G; Werner, M; Winer, B L; Wood, K S; Wood, M; Zaharijas, G

2015-01-01T23:59:59.000Z

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361

Measurement of the half-lives of ??As and ??Br high Z test of CVC (Standard Model) via superallowed Fermi decay  

E-Print Network [OSTI]

and content by: Pea Carl A. Ga ' rdi (Chairman of C mittee) Robert E. Tribble (Member) Jos ph B. atowitz (Member) &r Richard L. Arnowitt (Head of Department) May 1988 111 ABSTRACT Measurement of the Half-Lives of As and Br High Z Test of' CVC... (Standard Model) via Superallowed Fermi Decay. (May 1988) Robert Harry Burch Jr. , B. S. , Hniversity of Texas at San Antonio Chairman of Advisory Committee: Dr. Carl Gagliardi The half-lives of the superallowed Fermi P-decays of As and Br have been...

Burch, Robert Harry

2012-06-07T23:59:59.000Z

362

Discussion on the energy content of the galactic dark matter Bose-Einstein condensate halo in the Thomas-Fermi approximation  

E-Print Network [OSTI]

We show that the galactic dark matter halo, considered composed of an axionlike particles Bose-Einstein condensate \\cite{pir12} trapped by a self-graviting potential \\cite{boh07}, may be stable in the Thomas-Fermi approximation since appropriate choices for the dark matter particle mass and scattering length are made. The demonstration is performed by means of the calculation of the potential, kinetic and self-interaction energy terms of a galactic halo described by a Boehmer-Harko density profile. We discuss the validity of the Thomas-Fermi approximation for the halo system, and show that the kinetic energy contribution is indeed negligible.

J. C. C. de Souza; M. O. C. Pires

2014-01-23T23:59:59.000Z

363

Single-particle spectral density of the unitary Fermi gas: Novel approach based on the operator product expansion, sum rules and the maximum entropy method  

E-Print Network [OSTI]

Making use of the operator product expansion, we derive a general class of sum rules for the imaginary part of the single-particle self-energy of the unitary Fermi gas. The sum rules are analyzed numerically with the help of the maximum entropy method, which allows us to extract the single-particle spectral density as a function of both energy and momentum. These spectral densities contain basic information on the properties of the unitary Fermi gas, such as the dispersion relation and the superfluid pairing gap, for which we obtain reasonable agreement with the available results based on quantum Monte-Carlo simulations.

Gubler, Philipp; Hatsuda, Tetsuo; Nishida, Yusuke

2015-01-01T23:59:59.000Z

364

Unusual light in dark space revealed by Los Alamos, NASA  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Unusual light in dark space revealed by Los Alamos, NASA Unusual light in dark space revealed by Los Alamos, NASA By looking at the dark spaces between visible galaxies and stars...

365

Two Studies Reveal Details of Lithium-Battery Function  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Two Studies Reveal Details of Lithium-Battery Function Two Studies Reveal Details of Lithium-Battery Function Print Wednesday, 27 February 2013 00:00 Our way of life is deeply...

366

Study Reveals Challenges and Opportunities Related to Vessels...  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

Study Reveals Challenges and Opportunities Related to Vessels for U.S. Offshore Wind Study Reveals Challenges and Opportunities Related to Vessels for U.S. Offshore Wind October 1,...

367

Fermi edge singularities in the mesoscopic regime: Photoabsorption spectra Martina Hentschel,1,2 Denis Ullmo,2,3 and Harold U. Baranger2  

E-Print Network [OSTI]

of the number M of particles. This effect is known as the Anderson orthogonality catastrophe AOC .7 As a result of AOC, the photoabsorption cross sec- tion A will be power law suppressed for energies near the threshold energy Fermi edge th. In the x-ray edge problem, AOC competes with a second, counteracting many

Baranger, Harold U.

368

Type A Accident Investigation of the June 21, 2001, Drilling Rig Operator Injury at the Fermi National Accelerator Laboratory, August 2001  

Broader source: Energy.gov [DOE]

On June 21, 2001, at approximately 9:40 A.M., a construction sub-tier contractor employee (the “Operator”) at the Fermi National Accelerator Laboratory (Fermilab) received serious head injuries requiring hospitalization when he was struck by part of the drilling rig (a “tong”) that he was operating.

369

Fitting the Fermi-LAT GeV excess: on the importance of the propagation of electrons from dark matter  

E-Print Network [OSTI]

An excess of gamma rays at GeV energies has been detected in the Fermi-LAT data. This signal comes from a narrow region around the Galactic Center and has been interpreted as possible evidence for light (30 GeV) dark matter particles. Focussing on the prompt gamma-ray emission, previous works found that the best fit to the data corresponds to annihilations proceeding into b quarks, with a dark matter profile going as r^{-1.2}. We show that this is not the only possible annihilation set-up. More specifically, we show how including the contributions to the gamma-ray spectrum from inverse Compton scattering and bremsstrahlung from electrons produced in dark matter annihilations, and undergoing diffusion through the Galactic magnetic field, significantly affects the spectrum for leptonic final states. This drastically changes the interpretation of the excess in terms of dark matter.

Lacroix, Thomas

2015-01-01T23:59:59.000Z

370

Variational Fermi–hypernetted-chain approximation [FHNC/?(r)] calculations with ?z-dependent correlations in liquid He3  

Science Journals Connector (OSTI)

The ground state of liquid He3 at zero temperature is approximated by a Jastrow two-body trial wave function including ?z-dependent correlations. The variational calculations are performed in the framework of the Fermi-hypernetted-chain (FHNC) approximation, and the elementary diagrams are estimated with two different extensions of the interpolating equation approach [FHNC/?(r)] [Fabrocini and Rosati, Nuovo Cimento D 1, 615 (1982)]. A comparison with a variational Monte Carlo calculation [Kürten and Clark, Phys. Rev. B 30, 1342 (1984)] shows good agreement for the expectation values of the total, kinetic, and potential energies. The increase of the total energy over a ?z-independent calculation, working with a semioptimized correlation function, is approximately 0.2 K at the equilibrium density for both Lennard-Jones and Aziz HFDHE2 potentials.

F. Arias de Saavedra and E. Buendría

1990-10-01T23:59:59.000Z

371

Fermi level de-pinning of aluminium contacts to n-type germanium using thin atomic layer deposited layers  

SciTech Connect (OSTI)

Fermi-level pinning of aluminium on n-type germanium (n-Ge) was reduced by insertion of a thin interfacial dielectric by atomic layer deposition. The barrier height for aluminium contacts on n-Ge was reduced from 0.7?eV to a value of 0.28?eV for a thin Al{sub 2}O{sub 3} interfacial layer (?2.8?nm). For diodes with an Al{sub 2}O{sub 3} interfacial layer, the contact resistance started to increase for layer thicknesses above 2.8?nm. For diodes with a HfO{sub 2} interfacial layer, the barrier height was also reduced but the contact resistance increased dramatically for layer thicknesses above 1.5?nm.

Gajula, D. R., E-mail: dgajula01@qub.ac.uk; Baine, P.; Armstrong, B. M.; McNeill, D. W. [School of Electronics, Electrical Engineering and Computer Science, Queen's University Belfast, Ashby Building, Stranmillis Road, Belfast BT9 5AH (United Kingdom)] [School of Electronics, Electrical Engineering and Computer Science, Queen's University Belfast, Ashby Building, Stranmillis Road, Belfast BT9 5AH (United Kingdom); Modreanu, M.; Hurley, P. K. [Tyndall National Institute, University College Cork, Lee Maltings, Cork (Ireland)] [Tyndall National Institute, University College Cork, Lee Maltings, Cork (Ireland)

2014-01-06T23:59:59.000Z

372

Improved analytical representation of combinations of Fermi-Dirac integrals for finite-temperature density functional calculations  

E-Print Network [OSTI]

Smooth, highly accurate analytical representations of Fermi-Dirac (FD) integral combinations important in free-energy density functional calculations are presented. Specific forms include those that occur in the local density approximation (LDA), generalized gradient approximation (GGA), and fourth-order gradient expansion of the non-interacting free energy as well as in the LDA and second-order gradient expansion for exchange. By construction, all the representations and their derivatives of any order are continuous on the full domains of their independent variables. The same type of technique provides an analytical representation of the function inverse to the FD integral of order $1/2$. It plays an important role in physical problems related to the electron gas at finite temperature. From direct evaluation, the quality of these improved representations is shown to be substantially superior to existing ones, many of which were developed before the era of large-scale computation or early in the era.

Karasiev, Valentin V; Trickey, S B

2014-01-01T23:59:59.000Z

373

The Spectrum of the Isotropic Diffuse Gamma-Ray Emission Derived From First-Year Fermi Large Area Telescope Data  

SciTech Connect (OSTI)

We report on the first Fermi Large Area Telescope (LAT) measurements of the so-called 'extra-galactic' diffuse {gamma}-ray emission (EGB). This component of the diffuse {gamma}-ray emission is generally considered to have an isotropic or nearly isotropic distribution on the sky with diverse contributions discussed in the literature. The derivation of the EGB is based on detailed modelling of the bright foreground diffuse Galactic {gamma}-ray emission (DGE), the detected LAT sources and the solar {gamma}-ray emission. We find the spectrum of the EGB is consistent with a power law with differential spectral index {gamma} = 2.41 {+-} 0.05 and intensity, I(> 100 MeV) = (1.03 {+-} 0.17) x 10{sup -5} cm{sup -2} s{sup -1} sr{sup -1}, where the error is systematics dominated. Our EGB spectrum is featureless, less intense, and softer than that derived from EGRET data.

Abdo, A. A.

2011-08-19T23:59:59.000Z

374

Thermal Hall conductivity of marginal Fermi liquids subject to out-of-plane impurities in high-Tc cuprates  

Science Journals Connector (OSTI)

The effect of out-of-plane impurities on the thermal Hall conductivity ?xy of in-plane marginal-Fermi-liquid (MFL) quasiparticles in high-Tc cuprates is examined by following the work on electrical Hall conductivity ?xy by Varma and Abraham [Phys. Rev. Lett. 86, 4652 (2001)]. It is shown that the effective Lorentz force exerted by these impurities is a weak function of energies of the MFL quasiparticles, resulting in nearly the same temperature dependence of ?xy/T and ?xy, indicative of obedience of the Wiedemann-Franz law. The inconsistency of the theoretical result with the experimental one is speculated to be the consequence of the different amounts of out-of-plane impurities in the two YBaCuO samples used for the ?xy and ?xy measurements.

Mei-Rong Li

2002-04-30T23:59:59.000Z

375

ORNL research reveals new challenges for mercury cleanup | ornl...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Jennifer Brouner Communications 865.241.0709 ORNL research reveals new challenges for mercury cleanup ORNL researchers are learning more about the microbial processes that convert...

376

ALS Capabilities Reveal Multiple Functions of Ebola Virus  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

ALS Capabilities Reveal Multiple Functions of Ebola Virus Print A central dogma of molecular biology is that a protein's sequence dictates its fold, and the fold dictates its...

377

Rechargeable Heat Battery's Secret Revealed: Solar Energy Capture...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Rechargeable Heat Battery Rechargeable Heat Battery's Secret Revealed Solar energy capture in chemical form makes it storable and transportable January 11, 2011 | Tags: Chemistry,...

378

DOE Energy Star Testing Reveals Inefficient ASKO Dishwasher | Department of  

Broader source: Energy.gov (indexed) [DOE]

Energy Star Testing Reveals Inefficient ASKO Dishwasher Energy Star Testing Reveals Inefficient ASKO Dishwasher DOE Energy Star Testing Reveals Inefficient ASKO Dishwasher June 1, 2010 - 2:07pm Addthis DOE testing in support of the Energy Star program has revealed that an ASKO dishwasher (model D5122XXLB), which the company had claimed was Energy Star compliant, consumes more energy than permitted by the Energy Star program. Test results for the ASKO model at issue show that, when tested in accordance with DOE's test procedure, it consumed 12 percent more energy than the Energy Star requirement. Based on this testing, DOE is referring ASKO Model D5122XXLB to the U.S. Environmental Protection Agency for appropriate action with respect to the Energy Star program. DOE's testing revealed that dishwasher model D5122XXLB also may not meet

379

Emergence of multiple Fermi surface maps in angle-resolved photoemission from Bi2Sr2CaCu2O8+?  

Science Journals Connector (OSTI)

We report angle-resolved photoemission spectra (ARPES) for emission from the Fermi energy (EF) over a large area of the (kx,ky) plane using 21.2 and 32 eV photon energies in two distinct polarizations from an optimally doped single crystal of Bi2Sr2CaCu2O8+? (Bi2212), together with extensive first-principles simulations of the ARPES intensities. The results display a wide-ranging level of accord between theory and experiment, demonstrating that the ARPES matrix elements can produce a striking variety of Fermi surface maps, especially in the presence of secondary features arising from modulations of the underlying tetragonal system. Our analysis demonstrates how the energy and polarization dependency of the ARPES matrix element can help to disentangle the primary contributions to the spectrum from the secondary features and indicates that secondary features reflect a direct modulation of the CuO2 planes.

M. C. Asensio; J. Avila; L. Roca; A. Tejeda; G. D. Gu; M. Lindroos; R. S. Markiewicz; A. Bansil

2003-01-22T23:59:59.000Z

380

Isospin-breaking corrections to superallowed Fermi beta-decay in isospin- and angular-momentum-projected nuclear Density Functional Theory  

E-Print Network [OSTI]

Background: The superallowed beta-decay rates provide stringent constraints on physics beyond the Standard Model of particle physics. To extract crucial information about the electroweak force, small isospin-breaking corrections to the Fermi matrix element of superallowed transitions must be applied. Purpose: We perform systematic calculations of isospin-breaking corrections to superallowed beta-decays and estimate theoretical uncertainties related to the basis truncation, time-odd polarization effects related to the intrinsic symmetry of the underlying Slater determinants, and to the functional parametrization. Methods: We use the self-consistent isospin- and angular-momentum-projected nuclear density functional theory employing two density functionals derived from the density independent Skyrme interaction. Pairing correlations are ignored. Our framework can simultaneously describe various effects that impact matrix elements of the Fermi decay: symmetry breaking, configuration mixing, and long-range Coulomb polarization. Results: The isospin-breaking corrections to the I=0+,T=1 --> I=0+,T=1 pure Fermi transitions are computed for nuclei from A=10 to A=98 and, for the first time, to the Fermi branch of the I,T=1/2 --> I,T=1/2 transitions in mirror nuclei from A=11 to A=49. We carefully analyze various model assumptions impacting theoretical uncertainties of our calculations and provide theoretical error bars on our predictions. Conclusions: The overall agreement with empirical isospin-breaking corrections is very satisfactory. Using computed isospin-breaking corrections we show that the unitarity of the CKM matrix is satisfied with a precision better than 0.1%.

W. Satula; J. Dobaczewski; W. Nazarewicz; T. R. Werner

2012-10-25T23:59:59.000Z

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381

Thomas-Fermi for Al+ Following the discusions on the positive ions in the lecture notes, we need to find c'(0) so that  

E-Print Network [OSTI]

Thomas-Fermi for Al+ Following the discusions on the positive ions in the lecture notes, we need to find c'(0) so that x0 c' Hx0 L = -HZ - NLê Z = -1 ê13 for Al+ . After some trial-and-error, I find c' H.7649 Now make sure x0 c' Hx0 L = -1 ê13, AlTF.nb 1 #12;In[4]:= Z x c'@xD ê. chisol ê. 8x � x0

Murayama, Hitoshi

382

Hall, Seebeck, and Nernst Coefficients of Underdoped HgBa2CuO4+?: Fermi-Surface Reconstruction in an Archetypal Cuprate Superconductor  

DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

Charge-density-wave order has been observed in cuprate superconductors whose crystal structure breaks the square symmetry of the CuO2 planes, such as orthorhombic YBa2Cu3Oy (YBCO), but not so far in cuprates that preserve that symmetry, such as tetragonal HgBa2CuO4+? (Hg1201). We have measured the Hall (RH), Seebeck (S), and Nernst (?) coefficients of underdoped Hg1201 in magnetic fields large enough to suppress superconductivity. The high-field RH(T) and S(T) are found to drop with decreasing temperature and become negative, as also observed in YBCO at comparable doping. In YBCO, the negative RH and S are signatures of a small electron pocket caused by Fermi-surface reconstruction, attributed to charge-density-wave modulations observed in the same range of doping and temperature. We deduce that a similar Fermi-surface reconstruction takes place in Hg1201, evidence that density-wave order exists in this material. A striking similarity is also found in the normal-state Nernst coefficient ?(T), further supporting this interpretation. Given the model nature of Hg1201, Fermi-surface reconstruction appears to be common to all hole-doped cuprates, suggesting that density-wave order is a fundamental property of these materials.

Doiron-Leyraud, Nicolas; Lepault, S.; Cyr-Choinière, O.; Vignolle, B.; Grissonnanche, G.; Laliberté, F.; Chang, J.; Bariši?, N.; Chan, M. K.; Ji, L.; Zhao, X.; Li, Y.; Greven, M.; Proust, C.; Taillefer, Louis

2013-06-01T23:59:59.000Z

383

A fermi liquid electric structure and the nature of the carriers in high-T/sub c/ cuprates: A photoemission study  

SciTech Connect (OSTI)

We have performed angle-integrated and angle-resolved photoemission measurements at 20 K on well-characterized single crystals of high-T/sub c/ cuprates (both 1:2:3-type and 2:2:1:2-type) cleaved in situ, and find a relatively large, resolution limited Fermi edge which shows large amplitude variations with photon energy, indicative of band structure final state effects. The lineshapes of the spectra of the 1:2:3 materials as a function of photon energy are well reproduced by band structure predictions, indicating a correct mix of 2p and 3d orbitals on the calculations, while the energy positions of the peaks agree with calculated bands only to within /approx/0.5 eV. This may yet prove to reflect the effects of Coulomb correlation. We nevertheless conclude that a Fermi liquid approach to conductivity is appropriate. Angle-resolved data, while still incomplete, suggest agreement with the Fermi surface predicted by the LDA calculations. A BCS-like energy gap is observed in the 2:2:1:2 materials, whose magnitude is twice the weak coupling BCS value (i.e., 2/Delta/ = 7 KT/sub c/). 49 refs., 11 figs.

Arko, A.J.; List, R.S.; Bartlett, R.J.; Cheong, S.W.; Fisk, Z.; Thompson, J.D.; Olson, C.G.; Yang, A.B.; Liu, R.; Gu, C.; Veal, B.W.; Liu, J.Z.; Paulikas, A.P.; Vandervoort, K.; Claus, H.; Campuzano, J.C.; Schirber, J.E.; Shinn, N.D.

1989-01-01T23:59:59.000Z

384

Deviations from Fermi-liquid behavior in (2+1)-dimensional quantum electrodynamics and the normal phase of high-Tc superconductors  

Science Journals Connector (OSTI)

We argue that the gauge-fermion interaction in multiflavor quantum electrodynamics in (2+1) dimensions is responsible for non-Fermi-liquid behavior in the infrared, in the sense of leading to the existence of a nontrivial (quasi)fixed point that lies between the trivial fixed point (at infinite momenta) and the region where dynamical symmetry breaking and mass generation occurs. This quasifixed-point structure implies slowly varying, rather than fixed, couplings in the intermediate regime of momenta, a situation which resembles that of (four-dimensional) "walking technicolor" models of particle physics. The inclusion of wave-function renormalization yields marginal O(1N) corrections to the "bulk" non-Fermi-liquid behavior caused by the gauge inter-action in the limit of infinite flavor number. Such corrections lead to the appearance of modified critical exponents. In particular, at low temperatures there appear to be logarithmic scaling violations of the linear resistivity of the system of order O(1N). The connection with the anomalous normal-state properties of certain condensed-matter systems relevant for high-temperature superconductivity is briefly discussed. The relevance of the large (flavor) N expansion to the Fermi-liquid problem is emphasized. As a partial result of our analysis, we point out the absence of charge-density-wave instabilities from the effective low-energy theory, as a consequence of gauge invariance.

I. J. R. Aitchison and N. E. Mavromatos

1996-04-01T23:59:59.000Z

385

Time stretching of the GeV emission of GRBs: Fermi-LAT data vs geometrical model  

E-Print Network [OSTI]

It is known that the high energy $(> 100\\,\\text{MeV})$ emission of gamma-ray bursts is delayed with respect to the low energy emission. However, the dependence of light curves on energy has not been studied for the high energy bands. In this paper we consider the bursts observed by Fermi LAT from 2008 August 4 to 2011 August 1, for which at least $10$ photons were observed with the energy greater than $1\\,\\text{GeV}$. These include $4$ bursts: GRB 080916C, GRB 090510, GRB 090902B, and GRB 090926A. We use the Kolmogorov-Smirnov test to compare the light curves in the two bands, $100\\,\\text{MeV} 1\\,\\text{GeV}$. For GRB 080916C and GRB 090510 the light curves in the two bands are statistically compatible. However, for GRB 090926A, the higher-energy light curve is stretched compared to the lower-energy one with a statistical significance of $3.3 \\sigma$ and, for GRB 090902B, on the contrary, the lower-energy curve is stretched with $2.3 \\sigma$ significance. We argue that the observed diversity of stretching fac...

Piskunov, Maxim S

2014-01-01T23:59:59.000Z

386

The Fermi-Pasta-Ulam recurrence and related phenomena for 1D shallow-water waves in a finite basin  

SciTech Connect (OSTI)

Different regimes of the Fermi-Pasta-Ulam (FPU) recurrence are simulated numerically for fully nonlinear 'one-dimensional' potential water waves in a finite-depth flume between two vertical walls. In such systems, the FPU recurrence is closely related to the dynamics of coherent structures approximately corresponding to solitons of the integrable Boussinesq system. A simplest periodic solution of the Boussinesq model, describing a single soliton between the walls, is presented in analytic form in terms of the elliptic Jacobi functions. In the numerical experiments, it is observed that depending on the number of solitons in the flume and their parameters, the FPU recurrence can occur in a simple or complicated manner, or be practically absent. For comparison, the nonlinear dynamics of potential water waves over nonuniform beds is simulated, with initial states taken in the form of several pairs of colliding solitons. With a mild-slope bed profile, a typical phenomenon in the course of evolution is the appearance of relatively high (rogue) waves, while for random, relatively short-correlated bed profiles it is either the appearance of tall waves or the formation of sharp crests at moderate-height waves.

Ruban, V. P., E-mail: ruban@itp.ac.ru [Russian Academy of Sciences, Landau Institute for Theoretical Physics (Russian Federation)

2012-02-15T23:59:59.000Z

387

Confronting recent AMS-02 positron fraction and Fermi-LAT Extragalactic Gamma-Ray Background measurements with gravitino dark matter  

E-Print Network [OSTI]

The positron fraction measured by the space-based detectors PAMELA, Fermi-LAT and AMS-02 presents anomalous behaviour as energy increase. In particular AMS-02 observations provide compelling evidence for a new source of positrons and electrons. Its origin is unknown, it can be non-exotic (e.g. pulsars), be dark matter or maybe a mixture. We prove the gravitino of R-parity violating supersymmetric models as this source. As the gravitino is a spin 3/2 particle, it offers particular decay channels. We compute the electron, positron and gamma-ray fluxes produced by each gravitino decay channel as it would be detected at the Earth's position. Combining the flux from the different decay modes we can fit AMS-02 measurements of the positron fraction, as well as the electron and positron fluxes, with a gravitino dark matter mass in the range $1-2$ TeV and lifetime of $\\sim 1.0-0.8\\times 10^{26}$ s. The high statistics measurement of electron and positron fluxes, and the flattering in the behaviour of the positron frac...

Carquin, Edson; Gomez-Vargas, German A; Panes, Boris; Viaux, Nicolas

2015-01-01T23:59:59.000Z

388

FIVE NEW MILLISECOND PULSARS FROM A RADIO SURVEY OF 14 UNIDENTIFIED FERMI-LAT GAMMA-RAY SOURCES  

SciTech Connect (OSTI)

We have discovered five millisecond pulsars (MSPs) in a survey of 14 unidentified Fermi Large Area Telescope sources in the southern sky using the Parkes radio telescope. PSRs J0101-6422, J1514-4946, and J1902-5105 reside in binaries, while PSRs J1658-5324 and J1747-4036 are isolated. Using an ephemeris derived from timing observations of PSR J0101-6422 (P = 2.57 ms, DM = 12 pc cm{sup -3}), we have detected {gamma}-ray pulsations and measured its proper motion. Its {gamma}-ray spectrum (a power law of {Gamma} = 0.9 with a cutoff at 1.6 GeV) and efficiency are typical of other MSPs, but its radio and {gamma}-ray light curves challenge simple geometric models of emission. The high success rate of this survey-enabled by selecting {gamma}-ray sources based on their detailed spectral characteristics-and other similarly successful searches indicate that a substantial fraction of the local population of MSPs may soon be known.

Kerr, M. [W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States); Camilo, F. [Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States); Johnson, T. J. [National Academy of Sciences, Washington, DC 20001 (United States); Ferrara, E. C.; Harding, A. K. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Guillemot, L.; Kramer, M. [Max-Planck-Institut fuer Radioastronomie, Auf dem Huegel 69, 53121 Bonn (Germany); Hessels, J. [Netherlands Institute for Radio Astronomy (ASTRON), Postbus 2, 7990 AA Dwingeloo (Netherlands); Johnston, S.; Keith, M.; Reynolds, J. E. [CSIRO Astronomy and Space Science, Australia Telescope National Facility, Epping, NSW 1710 (Australia); Ransom, S. M. [National Radio Astronomy Observatory (NRAO), Charlottesville, VA 22903 (United States); Ray, P. S.; Wood, K. S. [Space Science Division, Naval Research Laboratory, Washington, DC 20375-5352 (United States); Sarkissian, J., E-mail: kerrm@stanford.edu, E-mail: fernando@astro.columbia.edu, E-mail: tyrel.j.johnson@gmail.com [CSIRO Parkes Observatory, Parkes, NSW 2870 (Australia)

2012-03-20T23:59:59.000Z

389

The radio/gamma-ray connection in Active Galactic Nuclei in the era of the Fermi Large Area Telescope  

E-Print Network [OSTI]

We present a detailed statistical analysis of the correlation between radio and gamma-ray emission of the Active Galactic Nuclei (AGN) detected by Fermi during its first year of operation, with the largest datasets ever used for this purpose. We use both archival interferometric 8.4 GHz data (from the VLA and ATCA, for the full sample of 599 sources) and concurrent single-dish 15 GHz measurements from the Owens Valley Radio Observatory (OVRO, for a sub sample of 199 objects). Our unprecedentedly large sample permits us to assess with high accuracy the statistical significance of the correlation, using a surrogate-data method designed to simultaneously account for common-distance bias and the effect of a limited dynamical range in the observed quantities. We find that the statistical significance of a positive correlation between the cm radio and the broad band (E>100 MeV) gamma-ray energy flux is very high for the whole AGN sample, with a probability <1e-7 for the correlation appearing by chance. Using the...

Ackermann, M; Allafort, A; Angelakis, E; Axelsson, M; Baldini, L; Ballet, J; Barbiellini, G; Bastieri, D; Bellazzini, R; Berenji, B; Blandford, R D; Bloom, E D; Bonamente, E; Borgland, A W; Bouvier, A; Bregeon, J; Brez, A; Brigida, M; Bruel, P; Buehler, R; Buson, S; Caliandro, G A; Cameron, R A; Cannon, A; Caraveo, P A; Casandjian, J M; Cavazzuti, E; Cecchi, C; Charles, E; Chekhtman, A; Cheung, C C; Ciprini, S; Claus, R; Cohen-Tanugi, J; Cutini, S; de Palma, F; Dermer, C D; Silva, E do Couto e; Drell, P S; Dubois, R; Dumora, D; Escande, L; Favuzzi, C; Fegan, S J; Focke, W B; Fortin, P; Frailis, M; Fuhrmann, L; Fukazawa, Y; Fusco, P; Gargano, F; Gasparrini, D; Gehrels, N; Giglietto, N; Giommi, P; Giordano, F; Giroletti, M; Glanzman, T; Godfrey, G; Grandi, P; Grenier, I A; Guiriec, S; Hadasch, D; Hayashida, M; Hays, E; Healey, S E; J, G; Johnson, A S; Kamae, T; Katagiri, H; Kataoka, J; Kn, J; Kuss, M; Lande, J; Lee, S -H; Longo, F; Loparco, F; Lott, B; Lovellette, M N; Lubrano, P; Makeev, A; Max-Moerbeck, W; Mazziotta, M N; McEnery, J E; Mehault, J; Michelson, P F; Mizuno, T; Monte, C; Monzani, M E; Morselli, A; Moskalenko, I V; Murgia, S; Naumann-Godo, M; Nishino, S; Nolan, P L; Norris, J P; Nuss, E; Ohsugi, T; Okumura, A; Omodei, N; Orlando, E; Ormes, J F; Ozaki, M; Paneque, D; Pavlidou, V; Pelassa, V; Pepe, M; Pesce-Rollins, M; Pierbattista, M; Piron, F; Porter, T A; Rain, S; Razzano, M; Readhead, A; Reimer, A; Reimer, O; Richards, J L; Romani, R W; Sadrozinski, H F -W; Scargle, J D; Sgr, C; Siskind, E J; Smith, P D; Spandre, G; Spinelli, P; Strickman, M S; Suson, D J; Takahashi, H; Tanaka, T; Taylor, G B; Thayer, J G; Thayer, J B; Thompson, D J; Torres, D F; Tosti, G; Tramacere, A; Troja, E; Vandenbroucke, J; Vianello, G; Vitale, V; Waite, A P; Wang, P; Winer, B L; Wood, K S; Yang, Z; Ziegler, M

2011-01-01T23:59:59.000Z

390

Synchrotron Cooling in Energetic Gamma-Ray Bursts Observed by the Fermi Gamma-Ray Burst Monitor  

E-Print Network [OSTI]

We study the time-resolved spectra of eight GRBs observed by Fermi GBM in its first five years of mission, with 1 keV - 1 MeV fluence $f>1.0\\times10^{-4}$ erg cm$^{-2}$ and signal-to-noise level $\\text{S/N}\\geq10.0$ above 900 keV. We aim to constrain in detail the spectral properties of GRB prompt emission on a time-resolved basis and to discuss the theoretical implications of the fitting results in the context of various prompt emission models. We perform time-resolved spectral analysis using a variable temporal binning technique according to optimal S/N criteria, resulting in a total of 299 time-resolved spectra. We fit the Band function to all spectra and obtain the distributions for the low-energy power-law index $\\alpha$, the high-energy power-law index $\\beta$, the peak energy in the observed $\

Yu, Hoi-Fung; van Eerten, Hendrik; Burgess, J Michael; Bhat, P Narayana; Briggs, Michael S; Connaughton, Valerie; Diehl, Roland; Goldstein, Adam; Gruber, David; Jenke, Peter A; von Kienlin, Andreas; Kouveliotou, Chryssa; Paciesas, William S; Pelassa, Veronique; Preece, Robert D; Roberts, Oliver J; Zhang, Bin-Bin

2014-01-01T23:59:59.000Z

391

Constraining Dark Matter Models from a Combined Analysis of Milky Way Satellites with the Fermi Large Area Telescope  

SciTech Connect (OSTI)

Satellite galaxies of the Milky Way are among the most promising targets for dark matter searches in gamma rays. We present a search for dark matter consisting of weakly interacting massive particles, applying a joint likelihood analysis to 10 satellite galaxies with 24 months of data of the Fermi Large Area Telescope. No dark matter signal is detected. Including the uncertainty in the dark matter distribution, robust upper limits are placed on dark matter annihilation cross sections. The 95% confidence level upper limits range from about 10{sup -26} cm{sup 3} s{sup -1} at 5 GeV to about 5 x 10{sup -23} cm{sup 3} s{sup -1} at 1 TeV, depending on the dark matter annihilation final state. For the first time, using gamma rays, we are able to rule out models with the most generic cross section ({approx}3 x 10{sup -26} cm{sup 3} s{sup -1} for a purely s-wave cross section), without assuming additional boost factors.

Ackermann, M.; Ajello, M.; /Stanford U., HEPL /Taiwan, Natl. Taiwan U. /SLAC; Albert, A.; /Taiwan, Natl. Taiwan U. /Ohio State U.; Atwood, W.B.; /UC, Santa Cruz; Baldini, L.; /INFN, Pisa; Ballet, J.; /DAPNIA, Saclay; Barbiellini, G.; /INFN, Trieste /Trieste U.; Bastieri, D.; /INFN, Padua /Padua U.; Bechtol, K.; /Stanford U., HEPL /Taiwan, Natl. Taiwan U. /SLAC; Bellazzini, R.; /INFN, Pisa; Berenji, B.; Blandford, R.D.; Bloom, E.D.; /Stanford U., HEPL /Taiwan, Natl. Taiwan U. /SLAC; Bonamente, E.; /INFN, Perugia /Perugia U.; Borgland, A.W.; /Stanford U., HEPL /Taiwan, Natl. Taiwan U. /SLAC; Bregeon, J.; /INFN, Pisa; Brigida, M.; /Bari Polytechnic /INFN, Bari; Bruel, P.; /Ecole Polytechnique; Buehler, R.; /Stanford U., HEPL /Taiwan, Natl. Taiwan U. /SLAC; Burnett, T.H.; /Washington U., Seattle; Buson, S.; /INFN, Padua /Padua U. /ICE, Bellaterra /Stanford U., HEPL /Taiwan, Natl. Taiwan U. /SLAC /INFN, Rome /Rome U. /IASF, Milan /IASF, Milan /DAPNIA, Saclay /INFN, Perugia /Perugia U. /Stanford U., HEPL /Taiwan, Natl. Taiwan U. /SLAC /Artep Inc. /Stanford U., HEPL /Taiwan, Natl. Taiwan U. /SLAC /ASDC, Frascati /Perugia U. /Stanford U., HEPL /Taiwan, Natl. Taiwan U. /SLAC /Montpellier U. /Stockholm U. /Stockholm U., OKC /ASDC, Frascati /ASDC, Frascati /Udine U. /INFN, Trieste /Bari Polytechnic /INFN, Bari /Naval Research Lab, Wash., D.C. /Stanford U., HEPL /Taiwan, Natl. Taiwan U. /SLAC /Montpellier U. /Bari Polytechnic /INFN, Bari /Ecole Polytechnique /NASA, Goddard /Hiroshima U. /Stanford U., HEPL /Taiwan, Natl. Taiwan U. /SLAC /Bari Polytechnic /INFN, Bari /INFN, Bari /ASDC, Frascati /NASA, Goddard /INFN, Perugia /Perugia U. /Bari Polytechnic /INFN, Bari /Bologna Observ. /Stanford U., HEPL /Taiwan, Natl. Taiwan U. /SLAC /DAPNIA, Saclay /Alabama U., Huntsville; /more authors..

2012-09-14T23:59:59.000Z

392

Multi-wavelength Emission from the Fermi Bubble II. Secondary Electrons and the Hadronic Model of the Bubble  

E-Print Network [OSTI]

We analyse the origin of the gamma-ray flux from the Fermi Bubbles (FBs) in the framework of the hadronic model in which gamma-rays are produced by collisions of relativistic protons with the protons of background plasma in the Galactic halo. It is assumed in this model that the observed radio emission from the FBs is due to synchrotron radiation of secondary electrons produced by $pp$ collisions. However, if these electrons loose their energy by the synchrotron and inverse-Compton, the spectrum of secondary electrons is too soft, and an additional arbitrary component of primary electrons is necessary in order to reproduce the radio data. Thus, a mixture of the hadronic and leptonic models is required for the observed radio flux. It was shown that if the spectrum of primary electrons is $\\propto E_e^{-2}$, the permitted range of the magnetic field strength is within 2 - 7 $\\mu$G region. The fraction of gamma-rays produced by $pp$ collisions can reach about 80% of the total gamma-ray flux from the FBs. If magn...

Cheng, K -S; Dogiel, V A; Ko, C -M

2014-01-01T23:59:59.000Z

393

General formula for the thermoelectric transport phenomena based on Fermi liquid theory: Thermoelectric power, Nernst coefficient, and thermal conductivity  

Science Journals Connector (OSTI)

On the basis of linear response transport theory, the general expressions for the thermoelectric transport coefficients, such as thermoelectric power (S), Nernst coefficient (?), and thermal conductivity (?), are derived by using Fermi liquid theory. The obtained expression is exact for the most singular term in terms of 1/?k* (?k* being the quasiparticle damping rate). We utilize Ward identities for the heat velocity which is derived by the local energy conservation law. The derived expressions enable us to calculate various thermoelectric transport coefficients in a systematic way, within the framework of the conserving approximation of Baym and Kadanoff. Thus the present expressions are very useful for studying strongly correlated electrons such as high-Tc superconductors, organic metals, and heavy fermion systems, where the current vertex correction (VC) is expected to play important roles. By using the derived expression, we calculate the thermal conductivity ? in a free-dispersion model up to second order with respect to the on-site Coulomb potential U. We find that it is slightly enhanced due to the VC for the heat current, although the VC for electron current makes the conductivity (?) of this system diverge, reflecting the absence of the umklapp process.

Hiroshi Kontani

2003-01-16T23:59:59.000Z

394

DOE Testing Reveals Samsung Refrigerator Does Not Meet Energy Star  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Testing Reveals Samsung Refrigerator Does Not Meet Energy Star Testing Reveals Samsung Refrigerator Does Not Meet Energy Star Requirements DOE Testing Reveals Samsung Refrigerator Does Not Meet Energy Star Requirements March 16, 2010 - 4:28pm Addthis DOE-initiated testing has revealed that a Samsung refrigerator (model RF26VAB), which the company had claimed was Energy Star compliant, consumed more energy than permitted by the Energy Star program. Test results for the Samsung model at issue show that, when tested in accordance with DOE's test procedure, it consumed between 7 and 11.4 percent more energy than the Energy Star requirement. Samsung is no longer manufacturing this model, although it may still be available from some retail outlets. Based on this testing, DOE is referring Samsung Model RF26VAB to the U.S.

395

New culturing tool reveals a full genome from single cells  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

New culturing tool reveals New culturing tool reveals New culturing tool reveals a full genome from single cells A new technique for genetic analysis, "gel microdroplets," helps scientists generate complete genomes from a single cell. March 15, 2013 Two GMD containing gut-community microcolonies are shown, with green fluorescence marking the DNA. Two GMD containing gut-community microcolonies are shown, with green fluorescence marking the DNA. Photo credit A. Dichosa, Los Alamos National Laboratory. Contact Nancy Ambrosiano Communications Office (505) 667-0471 Email We have demonstrated a novel approach for fully sequencing genomes of microorganisms found in complex communities. Gel microdroplet culturing reveals intraspecies genomic diversity within the human microbiome LOS ALAMOS, N. M., March 15, 2013-A new technique for genetic analysis,

396

Interaction proteomics reveals brain region-specific AMPA receptor complexes  

Science Journals Connector (OSTI)

Fast excitatory synaptic transmission in the brain is mediated by glutamate acting on postsynaptic AMPA receptors. Recent studies have revealed a substantial number of AMPA receptor auxiliary proteins, which potentially contribute to the regulation of ...

Ning Chen; Nikhil Janak Pandya; Frank Koopmans; Violeta Castelo-Székely; Roel C. van der Schors; August B. Smit; Ka Wan Li

2014-10-22T23:59:59.000Z

397

Alternate States of Proteins Revealed by Detailed Energy Landscape Mapping  

E-Print Network [OSTI]

Alternate States of Proteins Revealed by Detailed Energy Landscape Mapping Michael D. Tyka1 Keywords: Rosetta; alternative conformations; protein mobility; structure prediction; validation What through analysis of detailed protein energy landscapes generated by large-scale, native- enhanced sampling

Baker, David

398

Metabolic properties in stroked rats revealed by relaxation-enhanced...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

metabolic properties via 1 H MRS at ultra-high fields. Metabolic properties in stroked rats revealed by relaxation-enhanced MR spectroscopy at 21.1 T Noam Shemesh 1 , Jens T...

399

Inductively coupled plasma–reactive ion etching of c- and a-plane AlGaN over the entire Al composition range: Effect of BCl{sub 3} pretreatment in Cl{sub 2}/Ar plasma chemistry  

SciTech Connect (OSTI)

Inductively coupled plasma (ICP)–reactive ion etching (RIE) patterning is a standard processing step for UV and optical photonic devices based on III-nitride materials. There is little research on ICP-RIE of high Al-content AlGaN alloys and for nonpolar nitride orientations. The authors present a comprehensive study of the ICP-RIE of c- and a-plane AlGaN in Cl{sub 2}/Ar plasma over the entire Al composition range. The authors find that the etch rate decreases in general with increasing Al content, with different behavior for c- and a-plane AlGaN. They also study the effect of BCl{sub 3} deoxidizing plasma pretreatment. An ICP deoxidizing BCl{sub 3} plasma with the addition of argon is more efficient in removal of surface oxides from Al{sub x}Ga{sub 1?x}N than RIE alone. These experiments show that Al{sub x}Ga{sub 1?x}N etching is affected by the higher binding energy of AlN and the higher affinity of oxygen to aluminum compared to gallium, with oxides on a-plane AlGaN more difficult to etch as compared to oxides on c-plane AlGaN, specifically for high Al composition materials. The authors achieve reasonably high etch rate (?350 nm/min) for high Al-content materials with a smooth surface morphology at a low DC bias of ??45 VDC.

Shah, Amit P.; Laskar, Masihhur R.; Azizur Rahman, A.; Gokhale, Maheshwar R.; Bhattacharya, Arnab [Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005 (India)] [Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005 (India)

2013-11-15T23:59:59.000Z

400

Is the 130 GeV line real? A search for systematics in the Fermi-LAT data  

SciTech Connect (OSTI)

Our recent claims of a Galactic center feature in Fermi-LAT data at approximately 130 GeV have motivated a large number of papers proposing explanations ranging from dark matter annihilation to monoenergetic pulsar winds. Because of the importance of such interpretations for physics and astrophysics, a discovery will require not only additional data, but a thorough investigation of possible LAT systematics. While we do not have access to the details of each event reconstruction, we do have information about each event from the public event lists and spacecraft parameter files. These data allow us to search for suspicious trends that could indicate a spurious signal. We consider several hypotheses that might make an instrumental artifact more apparent at the Galactic center, and find them implausible. We also search for an instrumental signature in the Earth limb photons, which provide a smooth reference spectrum for null tests. We find no significant 130 GeV feature in the Earth limb sample. However, we do find a marginally significant 130 GeV feature in Earth limb photons with a limited range of detector incidence angles. This raises concerns about the 130 GeV Galactic center feature, even though we can think of no plausible model of instrumental behavior that connects the two. A modest amount of additional limb data would tell us if the limb feature is a statistical fluke. If the limb feature persists, it would raise doubts about the Pass 7 processing of E > 100 GeV events. At present we find no instrumental systematics that could plausibly explain the excess Galactic center emission at 130 GeV.

Finkbeiner, Douglas P.; Su, Meng [Institute for Theory and Computation, Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS-51, Cambridge, MA 02138 (United States); Weniger, Christoph, E-mail: dfinkbeiner@cfa.harvard.edu, E-mail: mengsu@cfa.harvard.edu, E-mail: weniger@mpp.mpg.de [Max-Planck-Institut für Physik, Föhringer Ring 6, 80805 München (Germany)

2013-01-01T23:59:59.000Z

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401

THE FERMI-GBM X-RAY BURST MONITOR: THERMONUCLEAR BURSTS FROM 4U 0614+09  

SciTech Connect (OSTI)

Thermonuclear bursts from slowly accreting neutron stars (NSs) have proven difficult to detect, yet they are potential probes of the thermal properties of the NS interior. During the first year of a systematic all-sky search for X-ray bursts using the Gamma-ray Burst Monitor aboard the Fermi Gamma-ray Space Telescope we have detected 15 thermonuclear bursts from the NS low-mass X-ray binary 4U 0614+09 when it was accreting at nearly 1% of the Eddington limit. We measured an average burst recurrence time of 12 {+-} 3 days (68% confidence interval) between 2010 March and 2011 March, classified all bursts as normal duration bursts and placed a lower limit on the recurrence time of long/intermediate bursts of 62 days (95% confidence level). We discuss how observations of thermonuclear bursts in the hard X-ray band compare to pointed soft X-ray observations and quantify such bandpass effects on measurements of burst radiated energy and duration. We put our results for 4U 0614+09 in the context of other bursters and briefly discuss the constraints on ignition models. Interestingly, we find that the burst energies in 4U 0614+09 are on average between those of normal duration bursts and those measured in long/intermediate bursts. Such a continuous distribution in burst energy provides a new observational link between normal and long/intermediate bursts. We suggest that the apparent bimodal distribution that defined normal and long/intermediate duration bursts during the last decade could be due to an observational bias toward detecting only the longest and most energetic bursts from slowly accreting NSs.

Linares, M.; Chakrabarty, D. [Massachusetts Institute of Technology, Kavli Institute for Astrophysics and Space Research, Cambridge, MA 02139 (United States); Connaughton, V.; Bhat, P. N.; Briggs, M. S.; Preece, R. [CSPAR and Physics Department, University of Alabama in Huntsville, Huntsville, AL 35899 (United States); Jenke, P.; Kouveliotou, C.; Wilson-Hodge, C. A. [Space Science Office, VP62, NASA/Marshall Space Flight Center, Huntsville, AL 35812 (United States); Van der Horst, A. J. [Astronomical Institute 'Anton Pannekoek', University of Amsterdam, NL-1090-GE Amsterdam (Netherlands); Camero-Arranz, A.; Finger, M.; Paciesas, W. S. [Universities Space Research Association, Huntsville, AL 35805 (United States); Beklen, E. [Physics Department, Suleyman Demirel University, 32260 Isparta (Turkey); Von Kienlin, A. [Max Planck Institute for Extraterrestrial Physics, Giessenbachstrasse, Postfach 1312, D-85748 Garching (Germany)

2012-12-01T23:59:59.000Z

402

SGR J1550-5418 BURSTS DETECTED WITH THE FERMI GAMMA-RAY BURST MONITOR DURING ITS MOST PROLIFIC ACTIVITY  

SciTech Connect (OSTI)

We have performed detailed temporal and time-integrated spectral analysis of 286 bursts from SGR J1550-5418 detected with the Fermi Gamma-ray Burst Monitor (GBM) in 2009 January, resulting in the largest uniform sample of temporal and spectral properties of SGR J1550-5418 bursts. We have used the combination of broadband and high time-resolution data provided with GBM to perform statistical studies for the source properties. We determine the durations, emission times, duty cycles, and rise times for all bursts, and find that they are typical of SGR bursts. We explore various models in our spectral analysis, and conclude that the spectra of SGR J1550-5418 bursts in the 8-200 keV band are equally well described by optically thin thermal bremsstrahlung (OTTB), a power law (PL) with an exponential cutoff (Comptonized model), and two blackbody (BB) functions (BB+BB). In the spectral fits with the Comptonized model, we find a mean PL index of -0.92, close to the OTTB index of -1. We show that there is an anti-correlation between the Comptonized E{sub peak} and the burst fluence and average flux. For the BB+BB fits, we find that the fluences and emission areas of the two BB functions are correlated. The low-temperature BB has an emission area comparable to the neutron star surface area, independent of the temperature, while the high-temperature BB has a much smaller area and shows an anti-correlation between emission area and temperature. We compare the properties of these bursts with bursts observed from other SGR sources during extreme activations, and discuss the implications of our results in the context of magnetar burst models.

Van der Horst, A. J.; Finger, M. H. [Universities Space Research Association, NSSTC, Huntsville, AL 35805 (United States); Kouveliotou, C. [Space Science Office, VP62, NASA/Marshall Space Flight Center, Huntsville, AL 35812 (United States); Gorgone, N. M. [Connecticut College, New London, CT 06320 (United States); Kaneko, Y.; Goegues, E.; Lin, L. [Sabanc Latin-Small-Letter-Dotless-I University, Orhanl Latin-Small-Letter-Dotless-I -Tuzla, Istanbul 34956 (Turkey); Baring, M. G. [Department of Physics and Astronomy, Rice University, MS-108, P.O. Box 1892, Houston, TX 77251 (United States); Guiriec, S.; Bhat, P. N.; Chaplin, V. L.; Goldstein, A. [University of Alabama, Huntsville, CSPAR, Huntsville, AL 35805 (United States); Granot, J. [Racah Institute of Physics, Hebrew University, Jerusalem 91904 (Israel); Watts, A. L. [Astronomical Institute 'Anton Pannekoek', University of Amsterdam, Postbus 94249, 1090 GE Amsterdam (Netherlands); Bissaldi, E.; Gruber, D. [Max Planck Institute for Extraterrestrial Physics, Giessenbachstrasse, Postfach 1312, 85748 Garching (Germany); Gehrels, N.; Harding, A. K. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Gibby, M. H.; Giles, M. M., E-mail: A.J.VanDerHorst@uva.nl [Jacobs Technology, Inc., Huntsville, AL (United States); and others

2012-04-20T23:59:59.000Z

403

GRB 090926A AND BRIGHT LATE-TIME FERMI LARGE AREA TELESCOPE GAMMA-RAY BURST AFTERGLOWS  

SciTech Connect (OSTI)

GRB 090926A was detected by both the Gamma-ray Burst Monitor and Large Area Telescope (LAT) instruments on board the Fermi Gamma-ray Space Telescope. Swift follow-up observations began {approx}13 hr after the initial trigger. The optical afterglow was detected for nearly 23 days post trigger, placing it in the long-lived category. The afterglow is of particular interest due to its brightness at late times, as well as the presence of optical flares at T0+10{sup 5} s and later, which may indicate late-time central engine activity. The LAT has detected a total of 16 gamma-ray bursts; nine of these bursts, including GRB 090926A, also have been observed by Swift. Of the nine Swift-observed LAT bursts, six were detected by UVOT, with five of the bursts having bright, long-lived optical afterglows. In comparison, Swift has been operating for five years and has detected nearly 500 bursts, but has only seen {approx}30% of bursts with optical afterglows that live longer than 10{sup 5} s. We have calculated the predicted gamma-ray fluence, as would have been seen by the Burst Alert Telescope (BAT) on board Swift, of the LAT bursts to determine whether this high percentage of long-lived optical afterglows is unique, when compared to BAT-triggered bursts. We find that, with the exception of the short burst GRB 090510A, the predicted BAT fluences indicate that the LAT bursts are more energetic than 88% of all Swift bursts and also have brighter than average X-ray and optical afterglows.

Swenson, C. A.; Roming, P. W. A.; Vetere, L.; Kennea, J. A. [Pennsylvania State University, 525 Davey Lab, University Park, PA 16802 (United States); Maxham, A.; Zhang, B. B.; Zhang, B. [University of Nevada, Las Vegas, Box 454002, 4505 Maryland Parkway, Las Vegas, NV 89154 (United States); Schady, P. [Max-Planck-Institut fuer extraterrestrische Physik, Garching (Germany); Holland, S. T. [Universities Space Research Association, 10227 Wincopin Circle, Suite 500, Columbia, MD 21044 (United States); Kuin, N. P. M.; Oates, S. R.; De Pasquale, M. [The UCL Mullard Space Science Laboratory, Holmbury St Mary, Surrey, RH5 6NT (United Kingdom); Page, K. L., E-mail: cswenson@astro.psu.ed [Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom)

2010-07-20T23:59:59.000Z

404

Flux and Photon Spectral Index Distributions of Fermi-LAT Blazars and Contribution to the Extragalactic Gamma-ray Background  

SciTech Connect (OSTI)

We present a determination of the distributions of gamma-ray flux - the so called LogN-LogS relation - and photon spectral index for the 352 blazars detected with a greater than approximately seven sigma detection threshold and located above {+-} 20{sup o} Galactic latitude by the Large Area Telescope of the Fermi Gamma-ray Space Telescope in its first year catalog. Because the flux detection threshold depends on the photon index, the observed raw distributions do not provide the true LogN-LogS counts or the true distribution of the photon index. We use the non-parametric methods developed by Efron and Petrosian to reconstruct the intrinsic distributions from the observed ones which account for the data truncations introduced by observational bias and includes the effects of the possible correlation among the two variables. We demonstrate the robustness of our procedures using a simulated data set of blazars and then apply these to the real data and find that for the population as a whole the intrinsic flux distribution can be represented by a broken power law of slopes -2.37 {+-} 0.13 and -1.70 {+-} 0.26, and the intrinsic photon index distribution can be represented by a Gaussian with mean 2.41 {+-} 0.13 and 1{sigma} width of 0.25 {+-} 0.03. We also find the intrinsic distributions for the sub-populations of BL Lac and FSRQs type blazars separately. We then calculate the contribution of blazars to the diffuse cosmic gamma-ray background radiation to be 28% {+-} 19%.

Singal, J.; /KIPAC, Menlo Park /SLAC /Stanford U.; Petrosian, V.; /KIPAC, Menlo Park /SLAC /Stanford U., Phys. Dept. /Stanford U., Appl. Phys. Dept.; Ajello, M.; /KIPAC, Menlo Park /SLAC /Stanford U.

2011-12-09T23:59:59.000Z

405

Rooted in Wonder: Joint Genome Institute Study Reveals Amazing World  

Broader source: Energy.gov (indexed) [DOE]

Rooted in Wonder: Joint Genome Institute Study Reveals Amazing Rooted in Wonder: Joint Genome Institute Study Reveals Amazing World Underfoot Rooted in Wonder: Joint Genome Institute Study Reveals Amazing World Underfoot August 13, 2012 - 2:33pm Addthis By developing a better understanding of the microbes that affect the growth of other plants (crops like corn or wheat) researchers may be able to improve their growth -- or provide better care for them in times of drought. By developing a better understanding of the microbes that affect the growth of other plants (crops like corn or wheat) researchers may be able to improve their growth -- or provide better care for them in times of drought. Charles Rousseaux Charles Rousseaux Senior Writer, Office of Science What Is A Weed It's also known as a mouse-ear cress. The scientific name is Arababidopsis thaliana.

406

DNA Duplication Revealed in New Beginnings | Department of Energy  

Broader source: Energy.gov (indexed) [DOE]

DNA Duplication Revealed in New Beginnings DNA Duplication Revealed in New Beginnings DNA Duplication Revealed in New Beginnings April 3, 2012 - 9:36am Addthis The DNA replication origin recognition complex (ORC) is a six-protein machine with a slightly twisted half-ring structure (yellow). ORC is proposed to wrap around and bend approximately 70 base pairs of double stranded DNA (red and blue). When a replication initiator Cdc6 (green) joins ORC, the partial ring is now complete and ready to load another protein onto the DNA. This last protein (not shown) is the enzyme that unwinds the double stranded DNA so each strand can be replicated. | Illustration courtesy of Brookhaven Lab. The DNA replication origin recognition complex (ORC) is a six-protein machine with a slightly twisted half-ring structure (yellow). ORC is

407

Simulations Reveal That Earth's Silica Is Predominantly Superficial - NERSC  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Reveal Reveal Earth's Silica Is Predominantly Superficial Simulations Reveal Earth's Silica Is Predominantly Superficial May 24, 2010 Silica is one of the most common minerals on Earth. Not only does it make up two-thirds of our planet's crust, it is also used to create a variety of materials from glass to ceramics, computer chips and fiber optic cables. Yet new quantum mechanics results generated by a team of physicists from Ohio State University (OSU) show that this mineral only populates our planet superficially-in other words, silica is relatively uncommon deep within the Earth. Cross-section of the Earth Using several of the largest supercomputers in the nation, including the National Energy Research Scientific Computing Center's (NERSC) Cray XT4 "Franklin" system, the team simulated the behavior of silica in

408

Arizona EV Infrastructure Plans Revealed | Department of Energy  

Broader source: Energy.gov (indexed) [DOE]

EV Infrastructure Plans Revealed EV Infrastructure Plans Revealed Arizona EV Infrastructure Plans Revealed November 5, 2010 - 3:21pm Addthis An electric vehicle uses a charging station. | Media photo from ECOtality An electric vehicle uses a charging station. | Media photo from ECOtality Joshua DeLung What are the key facts? 180 residential and 230 public charging stations to be installed Blueprints signify clearing of last major hurdle before implementation begins The EV Project has been recognized as one of the top Recovery Act projects Out in the desert, a revolution in automotive technology is happening. Some Arizona drivers are taking part in an innovative new project that will help develop electric vehicle infrastructure and gather crucial research data toward ensuring the vitality of EVs for years to come.

409

Engines - Particulate Studies - Revealing the True Nature of Diesel  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Engine Nanoparticle Research: Revealing the True Nature of Diesel Particulates Engine Nanoparticle Research: Revealing the True Nature of Diesel Particulates Thermophoretic sampling device Argonne's test engine with the thermophoretic sampling device attached. Nanostructure of graphitic diesel soot under high engine load A transmission electron microscope reveals the nanostructures of graphitic diesel soot sampled under high engine loads. Morphology of particles collected from diesel combustion with iso-paraffin-enriched fuel. Morphology of particles collected from diesel combution with iso-paraffin-enriched fuel. Amorphous soot particle collected from biodiesel combustion undera low-temperature condition. Amorphous soot particle collected from biodiesel combustion under low temperature conditions. Researchers have many ideas about how to reduce the soot produced by diesel

410

Historical forest baselines reveal potential for continued carbon sequestration  

E-Print Network [OSTI]

Historical forest baselines reveal potential for continued carbon sequestration Jeanine M-based studies suggest that land-use history is a more important driver of carbon sequestration in these systems agricultural lands are being promoted as important avenues for future carbon sequestration (8). But the degree

Mladenoff, David

411

HYDRAULIC STIMULATION OF NATURAL FRACTURES AS REVEALED BY INDUCED MICROEARTHQUAKES,  

E-Print Network [OSTI]

-1- HYDRAULIC STIMULATION OF NATURAL FRACTURES AS REVEALED BY INDUCED MICROEARTHQUAKES, CARTHAGE, December, 2001 Manuscript # 01066 LAUR# 01-1204 #12;Hydraulic Stimulation of Natural Fractures -2- ABSTRACT We have produced a high-resolution microseismic image of a hydraulic fracture stimulation

412

DYNAMIC INVARIANTS IN PROTEIN FOLDING PATHWAYS REVEALED BY TENSOR ANALYSIS  

E-Print Network [OSTI]

DYNAMIC INVARIANTS IN PROTEIN FOLDING PATHWAYS REVEALED BY TENSOR ANALYSIS Arvind Ramanathan Lane a spatio-temporal analysis of protein folding pathways. We applied our method to folding simulations of how a protein folds into its functionally relevant conformations. Protein folding pathways span over

Langmead, Christopher James

413

Real-Time Redox Measurements during Endoplasmic Reticulum Stress Reveal  

E-Print Network [OSTI]

Real-Time Redox Measurements during Endoplasmic Reticulum Stress Reveal Interlinked Protein Folding.10.011 SUMMARY Disruption of protein folding in the endoplasmic reticulum (ER) causes unfolded proteins to accumu is active. Because ER redox po- tential is optimized for oxidative protein folding, we reasoned

Mullins, Dyche

414

Fermi-level depinning and contact resistance reduction in metal/n-Ge junctions by insertion of W-encapsulating Si cluster films  

SciTech Connect (OSTI)

We demonstrate Fermi-level depinning in metal/Ge junctions and a significant reduction of specific contact resistivity of n-Ge by inserting an ultra-thin semiconducting Si-rich W silicide film (WSi{sub n}, n?=?12–14) composed of W-encapsulating Si clusters. Dependence of the specific contact resistivity on the electron Schottky barrier height followed the ideal exponential relation for various contact metal species. This result indicates that the insertion of the WSi{sub n} film provides a negligible contribution to contact resistivity because its tunneling resistance is very low owing to the low offset of the conduction band edge of Ge.

Okada, Naoya [Nanoelectronics Research Institute, National Institute of Advanced Industrial Science and Technology, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8562 (Japan); Institute of Applied Physics, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573 (Japan); Uchida, Noriyuki [Nanoelectronics Research Institute, National Institute of Advanced Industrial Science and Technology, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8562 (Japan); Kanayama, Toshihiko [Institute of Applied Physics, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573 (Japan); National Institute of Advanced Industrial Science and Technology, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568 (Japan)

2014-02-10T23:59:59.000Z

415

Fermi National Accelerator Laboratory  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

fiscal fiscal year 2013, Fermilab spent $131.6 million in the United States to purchase goods and services in 47 states and the District of Columbia. Procurements in Illinois accounted for approximately $50 million, and about $80 million was spent in other states. Fermilab Procurements Alabama, Arkansas, Arizona, Delaware, Idaho, Kentucky, Louisiana, Maine, Mississippi, Montana, North Dakota, Nevada, Oklahoma, Utah, Wyoming Connecticut, Georgia, Iowa, Kansas, Michigan, North Carolina, Rhode Island, Tennessee, Vermont $1,000,001-$5,000,000 Indiana, Maryland, New Hampshire, Washington Colorado, District of Columbia, Florida, Massachusetts, Missouri, Nebraska, New Jersey, New Mexico, Oregon, Pennsylvania, South Carolina, South Dakota, Texas, Wisconsin More than $5 million

416

Fermi molecular dynamics  

SciTech Connect (OSTI)

classical many body models supplemented by repulsive momentum-dependent potentials to simulate the Pauli and Heisenberg principles have been use with some success for nuclear and atomic bound state and collision problems. They are capable of describing mean ground state properties, hydrodynamics, shocks (if warranted by the physics), viscosity, correlations, clustering, fragmentation, etc. We have become interested in the Feldmeier Gaussian packet formulation since it is based on a variational principle using trial wave functions. We discuss some limitations of the model and discuss further directions of investigation.

Wilets, L.; Beck, W.

1991-01-01T23:59:59.000Z

417

Strongly interacting Fermi gases  

E-Print Network [OSTI]

Strongly interacting gases of ultracold fermions have become an amazingly rich test-bed for many-body theories of fermionic matter. Here we present our recent experiments on these systems. Firstly, we discuss high-precision ...

Bakr, W.

418

New Model of Earth's Interior Reveals Clues to Hotspot Volcanoes  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

New Model of New Model of Earth's Interior Reveals Clues to Hotspot Volcanoes New Model of Earth's Interior Reveals Clues to Hotspot Volcanoes October 29, 2013 | Tags: Basic Energy Sciences (BES), Geosciences, Hopper Contact: Linda Vu, +1 510 495 2402, lvu@lbl.gov volcanic-hotspots1.jpg This 3D view of the top 1,000 kilometers of Earth's mantle beneath the central Pacific shows the relationship between seismically-slow "plumes" and channels imaged in the UC Berkeley study. Green cones on the ocean floor mark islands associated with "hotspot" volcanoes, such as Hawaii and Tahiti. (Image courtesy of Berkeley Seismological Laboratory, UC Berkeley) Using supercomputers at the Department of Energy's National Energy Research Scientific Computing Center (NERSC), scientists have detected

419

Two Studies Reveal Details of Lithium-Battery Function  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Two Studies Reveal Details of Lithium-Battery Function Print Two Studies Reveal Details of Lithium-Battery Function Print Our way of life is deeply intertwined with battery technologies that have enabled a mobile revolution powering cell phones, laptops, medical devices, and cars. As conventional lithium-ion batteries approach their theoretical energy-storage limits, new technologies are emerging to address the long-term energy-storage improvements needed for mobile systems, electric vehicles in particular. Battery performance depends on the dynamics of evolving electronic and chemical states that, despite advances in material synthesis and structural probes, remain elusive and largely unexplored. At Beamlines 8.0.1 and 9.3.2, researchers studied lithium-ion and lithium-air batteries, respectively, using soft x-ray spectroscopy techniques. The detailed information they obtained about the evolution of electronic and chemical states will be indispensable for understanding and optimizing better battery materials.

420

NETL: News Release - Advanced Research Awards to Reveal Mechanisms of  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Advanced Research Awards to Reveal Mechanisms of Mercury Chemistry, Lead to Lower Mercury Emission Advanced Research Awards to Reveal Mechanisms of Mercury Chemistry, Lead to Lower Mercury Emission PITTSBURGH, PA - The Department of Energy has announced four awards totaling $1.4 million for advanced research to aid the removal of mercury from existing fossil-fueled power plants. The four new projects support the President's call for dramatic cuts in mercury emissions by providing an understanding of the mechanisms of mercury chemistry, and leading to novel approaches to measure and remove mercury from flue gas. Coal contains only trace amounts of mercury, but when coal is consumed to produce power, gaseous species of mercury are formed and emitted into the atmosphere. These emissions are the largest human-created source of mercury emissions in the United States, and may contribute to a variety of health and environmental problems.

Note: This page contains sample records for the topic "fermi reveals entire" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Favorable Supplies, Costs, Environmental Profile for Natural Gas Revealed  

Broader source: Energy.gov (indexed) [DOE]

Favorable Supplies, Costs, Environmental Profile for Natural Gas Favorable Supplies, Costs, Environmental Profile for Natural Gas Revealed in New Department of Energy Study Favorable Supplies, Costs, Environmental Profile for Natural Gas Revealed in New Department of Energy Study August 23, 2012 - 1:00pm Addthis Washington, DC - The nation's large resource base of natural gas can be used for cost-effective power generation, with environmental burdens coming primarily from fuel combustion, not resource extraction, according to a new Department of Energy (DOE) study. The report, Role of Alternative Energy Sources: Natural Gas Power Technology Assessment, was prepared by the Office of Fossil Energy's National Energy Technology Laboratory (NETL). Analysts focused on seven criteria to evaluate the role of natural gas in the U.S. energy supply

422

Obscure pulmonary masses: bronchial impaction revealed by CT  

SciTech Connect (OSTI)

Dilated bronchi impacted with mucus or tumor are recognized on standard chest radiographs because they are surrounded by aerated pulmonary parenchyma. When imaged in different projections, these lesions produce a variety of appearances that are generally familiar. This report characterizes less familiar computed tomographic (CT) findings in eight patients with pathologic bronchial distension of congenital, neoplastic, or infectious etiologies and correlates them with chest films. In seven patients, CT readily revealed dilated bronchi and/or regional lung hypodensity. In four of these cases, CT led to the initial suspicion of dilated bronchi. CT should be used early in the evaluation of atypical pulmonary mass lesions or to confirm suspected bronchial impaction because of the high probability it will reveal diagnostic features.

Pugatch, R.D.; Gale, M.E.

1983-11-01T23:59:59.000Z

423

Computer modeling reveals how surprisingly potent hepatitis C drug works  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Hepatitis C computer modeling Hepatitis C computer modeling Computer modeling reveals how surprisingly potent hepatitis C drug works A study reveals how daclatasvir targets one of its proteins and causes the fastest viral decline ever seen with anti-HCV drugs - within 12 hours of treatment. February 19, 2013 Los Alamos National Laboratory sits on top of a once-remote mesa in northern New Mexico with the Jemez mountains as a backdrop to research and innovation covering multi-disciplines from bioscience, sustainable energy sources, to plasma physics and new materials. Los Alamos National Laboratory sits on top of a once-remote mesa in northern New Mexico with the Jemez mountains as a backdrop to research and innovation covering multi-disciplines from bioscience, sustainable energy sources, to plasma physics and new materials.

424

Two Studies Reveal Details of Lithium-Battery Function  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Two Studies Reveal Details of Lithium-Battery Function Print Two Studies Reveal Details of Lithium-Battery Function Print Our way of life is deeply intertwined with battery technologies that have enabled a mobile revolution powering cell phones, laptops, medical devices, and cars. As conventional lithium-ion batteries approach their theoretical energy-storage limits, new technologies are emerging to address the long-term energy-storage improvements needed for mobile systems, electric vehicles in particular. Battery performance depends on the dynamics of evolving electronic and chemical states that, despite advances in material synthesis and structural probes, remain elusive and largely unexplored. At Beamlines 8.0.1 and 9.3.2, researchers studied lithium-ion and lithium-air batteries, respectively, using soft x-ray spectroscopy techniques. The detailed information they obtained about the evolution of electronic and chemical states will be indispensable for understanding and optimizing better battery materials.

425

Favorable Supplies, Costs, Environmental Profile for Natural Gas Revealed  

Broader source: Energy.gov (indexed) [DOE]

Favorable Supplies, Costs, Environmental Profile for Natural Gas Favorable Supplies, Costs, Environmental Profile for Natural Gas Revealed in New Department of Energy Study Favorable Supplies, Costs, Environmental Profile for Natural Gas Revealed in New Department of Energy Study August 23, 2012 - 1:00pm Addthis Washington, DC - The nation's large resource base of natural gas can be used for cost-effective power generation, with environmental burdens coming primarily from fuel combustion, not resource extraction, according to a new Department of Energy (DOE) study. The report, Role of Alternative Energy Sources: Natural Gas Power Technology Assessment, was prepared by the Office of Fossil Energy's National Energy Technology Laboratory (NETL). Analysts focused on seven criteria to evaluate the role of natural gas in the U.S. energy supply

426

High-Energy Gamma-Ray Emission From Solar Flares: Summary of Fermi LAT Detections and Analysis of Two M-Class Flares  

E-Print Network [OSTI]

We present the detections of 19 solar flares detected in high-energy gamma rays (above 100 MeV) with the Fermi Large Area Telescope (LAT) during its first four years of operation. Interestingly, all flares are associated with fairly fast Coronal Mass Ejections (CMEs) and are not all powerful X-ray flares. We then describe the detailed temporal, spatial and spectral characteristics of the first two long-lasting events: the 2011 March 7 flare, a moderate (M3.7) impulsive flare followed by slowly varying gamma-ray emission over 13 hours, and the 2011 June 7 M2.5 flare, which was followed by gamma-ray emission lasting for 2 hours. We compare the Fermi-LAT data with X-ray and proton data measurements from GOES and RHESSI. We argue that a hadronic origin of the gamma rays is more likely than a leptonic origin and find that the energy spectrum of the proton distribution softens after the 2011 March 7 flare, favoring a scenario with continuous acceleration at the flare site. This work suggests that proton acceleratio...

,

2013-01-01T23:59:59.000Z

427

GMRT DISCOVERY OF PSR J1544+4937: AN ECLIPSING BLACK-WIDOW PULSAR IDENTIFIED WITH A FERMI-LAT SOURCE  

SciTech Connect (OSTI)

Using the Giant Metrewave Radio Telescope, we performed deep observations to search for radio pulsations in the directions of unidentified Fermi-Large Area Telescope {gamma}-ray sources. We report the discovery of an eclipsing black-widow millisecond pulsar, PSR J1544+4937, identified with the uncataloged {gamma}-ray source FERMI J1544.2+4941. This 2.16 ms pulsar is in a 2.9 hr compact circular orbit with a very low mass companion (M{sub c} > 0.017M{sub Sun }). At 322 MHz this pulsar is found to be eclipsing for 13% of its orbit, whereas at 607 MHz the pulsar is detected throughout the low-frequency eclipse phase. Variations in the eclipse ingress phase are observed, indicating a clumpy and variable eclipsing medium. Moreover, additional short-duration absorption events are observed around the eclipse boundaries. Using the radio timing ephemeris we were able to detect {gamma}-ray pulsations from this pulsar, confirming it as the source powering the {gamma}-ray emission.

Bhattacharyya, B.; Roy, J.; Gupta, Y. [National Centre for Radio Astrophysics, Tata Institute of Fundamental Research, Pune 411 007 (India); Ray, P. S.; Wolff, M. T.; Wood, K. S. [Space Science Division, Naval Research Laboratory, Washington, DC 20375-5352 (United States); Bhattacharya, D. [Inter-University Centre for Astronomy and Astrophysics, Pune 411 007 (India); Romani, R. W.; Den Hartog, P. R.; Kerr, M.; Michelson, P. F. [W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States); Ransom, S. M. [National Radio Astronomy Observatory (NRAO), Charlottesville, VA 22903 (United States); Ferrara, E. C.; Harding, A. K. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Camilo, F. [Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States); Cognard, I. [Laboratoire de Physique et Chimie de l'Environnement, LPCE UMR 6115 CNRS, F-45071 Orleans Cedex 02 (France); Johnston, S.; Keith, M. [CSIRO Astronomy and Space Science, Australia Telescope National Facility, Epping, NSW 1710 (Australia); Saz Parkinson, P. M. [Santa Cruz Institute for Particle Physics, Department of Physics and Department of Astronomy and Astrophysics, University of California at Santa Cruz, Santa Cruz, CA 95064 (United States); Wood, D. L. [Praxis Inc., Alexandria, VA 22303 (United States)

2013-08-10T23:59:59.000Z

428

Fermi 130 GeV gamma-ray excess and dark matter annihilation in sub-haloes and in the Galactic centre  

SciTech Connect (OSTI)

We analyze publicly available Fermi-LAT high-energy gamma-ray data and confirm the existence of clear spectral feature peaked at E{sub ?} = 130 GeV. Scanning over the Galaxy we identify several disconnected regions where the observed excess originates from. Our best optimized fit is obtained for the central region of Galaxy with a clear peak at 130 GeV with local statistical significance 4.5?. The observed excess is not correlated with Fermi bubbles. We compute the photon spectra induced by dark matter annihilations into two and four standard model particles, the latter via two light intermediate states, and fit the spectra with data. Since our fits indicate sharper and higher signal peak than in the previous works, data favors dark matter direct two-body annihilation channels into photons or other channels giving only line-like spectra. If Einasto halo profile correctly predicts the central cusp of Galaxy, dark matter annihilation cross-section to two photons is of order ten percent of the standard thermal freeze-out cross-section. The large dark matter two-body annihilation cross-section to photons may signal a new resonance that should be searched for at the CERN LHC experiments.

Tempel, Elmo; Hektor, Andi; Raidal, Martti, E-mail: elmo@aai.ee, E-mail: andi.hektor@cern.ch, E-mail: martti.raidal@cern.ch [NICPB, Ravala 10, Tallinn 10143 (Estonia)

2012-09-01T23:59:59.000Z

429

Study of luminosity and spin-up relation in X-ray binary pulsars with long-term monitoring by MAXI/GSC and Fermi/GBM  

E-Print Network [OSTI]

We study the relation between luminosity and spin-period change in X-ray binary pulsars using long-term light curve obtained by the MAXI/GSC all-sky survey and pulse period data from the Fermi/GBM pulsar project. X-ray binaries, consisting of a highly magnetized neutron star and a stellar companion, originate X-ray emission according to the energy of the accretion matter onto the neutron star. The accretion matter also transfers the angular momentum at the Alfven radius, and then spin up the neutron star. Therefore, the X-ray luminosity and the spin-up rate are supposed to be well correlated. We analyzed the luminosity and period-change relation using the data taken by continuous monitoring of MAXI/GSC and Fermi/GBM for Be/X-ray binaries, GX 304$-$1, A 0535$+$26, GRO J1008$-$57, KS 1947$+$300, and 2S 1417$-$624, which occurred large outbursts in the last four years. We discuss the results comparing the obtained observed relation with that of the theoretical model by Ghosh \\& Lamb (1979).

Sugizaki, Mutsumi; Nakajima, Motoki; Yamaoka, Kazutaka

2015-01-01T23:59:59.000Z

430

E-Print Network 3.0 - analysis reveals co-upregulation Sample...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

analysis, the technique selects a subset of properties that are most likely to reveal an error... code program analysis model machine classifier fault-revealing properties Figure...

431

Archaeopteryx Feathers and Bone Chemistry Fully Revealed via Synchrotron  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Archaeopteryx Feathers and Bone Chemistry Fully Revealed via Archaeopteryx Feathers and Bone Chemistry Fully Revealed via Synchrotron Imaging Archaeopteryx specimens are important but extremely rare fossils. Due to their possession of both reptilian (jaws with teeth, long bony tail) and avian (feathered wings) characters, Archaeopteryx has been crucial in the development of Darwinian evolution. Despite their importance, no Archaeopteryx specimen has ever been chemically analyzed. This in large part may be explained by the analytical obstacles which preclude applying standard methods to such valuable specimens; destructive sampling is not an option and most non-destructive methods cannot handle large specimens. Furthermore, mapping using conventional methods is far too slow to enable chemical zonation to be reasonably determined. Mapping of trace element chemistry is of tremendous interest, however, because it opens a window into understanding several critical questions about Archaeopteryx in particular, and about fossil specimens in general. Preserved trace chemistry in bones and soft tissue may be remnants of the living organism, and therefore may give insight into life processes of extinct organisms. When mapping includes the embedding rock matrix, mass transfer between the fossil and the matrix can be constrained, hence giving information about mode of preservation. Chemical analysis can also resolve artefacts of the curation process. Finally, accurate chemical maps can also be useful for directing future work by highlighting regions that may be promising for other types of analysis including structural methods (CT, diffraction) or techniques that use other parts of the electromagnetic spectrum (infra-red).

432

Enrico Fermi Awards Ceremony for Dr. Allen J. Bard and Dr. Andrew Sessler, February 2014 (Presentations, including remarks by Energy Secretary, Dr. Ernest Moniz)  

ScienceCinema (OSTI)

The Fermi Award is a Presidential award and is one of the oldest and most prestigious science and technology honors bestowed by the U.S. Government. On February 3, 2014 it was conferred upon two exceptional scientists. The first to be recognized is Dr. Allen J. Bard, 'for international leadership in electrochemical science and technology, for advances in photoelectrochemistry and photocatalytic materials, processes, and devices, and for discovery and development of electrochemical methods including electrogenerated chemiluminescence and scanning electrochemical microscopy.' The other honoree is Dr. Andrew Sessler, 'for advancing accelerators as powerful tools of scientific discovery, for visionary direction of the research enterprise focused on challenges in energy and the environment, and for championing outreach and freedom of scientific inquiry worldwide.' Dr. Patricia Dehmer opened the ceremony, and Dr. Ernest Moniz presented the awards.

Moniz, Ernest [U.S. Energy Secretary

2014-08-22T23:59:59.000Z

433

Fermi/LAT Study of the Cygnus Loop Supernova Remnant: Discovery of a Point-like Source and of Spectral Differences in its gamma-ray emission  

E-Print Network [OSTI]

The Cygnus Loop is a nearby supernova remnant (SNR) observed across the electromagnetic spectrum. With the analysis of 6 years of Fermi/LAT data we find that, what previous studies had considered a single source, consists of an extended source plus a point-like source south-east of the SNR. The extended gamma-ray emission is well correlated with the thermal X-ray emission of the SNR, and the energy spectrum displays a pronounced maximum at $\\sim0.6$\\,GeV. However, in a region where the radio emission is strongly and distinctly polarized, the gamma-ray spectrum shows no sign of a break. Therefore, the spatially resolved gamma-ray emission permits the study of different interaction conditions of the SNR and the surrounding medium.

Reichardt, I; West, J; Safi-Harb, S; de Oña-Wilhelmi, E; Rico, J

2015-01-01T23:59:59.000Z

434

Demonstrating 1 nm-oxide-equivalent-thickness HfO{sub 2}/InSb structure with unpinning Fermi level and low gate leakage current density  

SciTech Connect (OSTI)

In this work, the band alignment, interface, and electrical characteristics of HfO{sub 2}/InSb metal-oxide-semiconductor structure have been investigated. By using x-ray photoelectron spectroscopy analysis, the conduction band offset of 1.78 ± 0.1 eV and valence band offset of 3.35 ± 0.1 eV have been extracted. The transmission electron microscopy analysis has shown that HfO{sub 2} layer would be a good diffusion barrier for InSb. As a result, 1 nm equivalent-oxide-thickness in the 4 nm HfO{sub 2}/InSb structure has been demonstrated with unpinning Fermi level and low leakage current of 10{sup ?4} A/cm{sup ?2}. The D{sub it} value of smaller than 10{sup 12} eV{sup ?1}cm{sup ?2} has been obtained using conduction method.

Trinh, Hai-Dang [Department of Materials Science and Engineering, National Chiao Tung University, 1001 University Road, Hsinchu, Taiwan (China) [Department of Materials Science and Engineering, National Chiao Tung University, 1001 University Road, Hsinchu, Taiwan (China); Department of Physics, Hanoi National University of Education, 136 Xuan Thuy, Cau Giay, Hanoi (Viet Nam); Lin, Yueh-Chin; Nguyen, Hong-Quan; Luc, Quang-Ho [Department of Materials Science and Engineering, National Chiao Tung University, 1001 University Road, Hsinchu, Taiwan (China)] [Department of Materials Science and Engineering, National Chiao Tung University, 1001 University Road, Hsinchu, Taiwan (China); Nguyen, Minh-Thuy; Duong, Quoc-Van; Nguyen, Manh-Nghia [Department of Physics, Hanoi National University of Education, 136 Xuan Thuy, Cau Giay, Hanoi (Viet Nam)] [Department of Physics, Hanoi National University of Education, 136 Xuan Thuy, Cau Giay, Hanoi (Viet Nam); Wang, Shin-Yuan [Department of Electronic Engineering, National Chiao Tung University 1001, University Rd., Hsinchu 300, Taiwan (China)] [Department of Electronic Engineering, National Chiao Tung University 1001, University Rd., Hsinchu 300, Taiwan (China); Yi Chang, Edward [Department of Materials Science and Engineering, National Chiao Tung University, 1001 University Road, Hsinchu, Taiwan (China) [Department of Materials Science and Engineering, National Chiao Tung University, 1001 University Road, Hsinchu, Taiwan (China); Department of Electronic Engineering, National Chiao Tung University 1001, University Rd., Hsinchu 300, Taiwan (China)

2013-09-30T23:59:59.000Z

435

Enrico Fermi Awards Ceremony for Dr. Mildred S. Dresselhaus and Dr. Burton Richter, May 2012 (Presentations, including remarks by Energy Secretary, Dr. Steven Chu)  

ScienceCinema (OSTI)

The Fermi Award is a Presidential award and is one of the oldest and most prestigious science and technology honors bestowed by the U.S. Government. On May 7, 2012 it was conferred upon two exceptional scientists: Dr. Mildred Dresselhaus, 'for her scientific leadership, her major contributions to science and energy policy, her selfless work in science education and the advancement of diversity in the scientific workplace, and her highly original and impactful research,' and Dr. Burton Richter, 'for the breadth of his influence in the multiple disciplines of accelerator physics and particle physics, his profound scientific discoveries, his visionary leadership as SLAC Director, his leadership of science, and his notable contributions in energy and public policy.' Dr. John Holder, Director of the White House Office of Science and Technology Policy, opened the ceremony, and Dr. Bill Brinkman, Director of DOE's Office of Science introduced the main speaker, Dr. Steven Chu, U.S. Energy Secretary.

Chu, Steven (U.S. Energy Secretary)

2012-06-28T23:59:59.000Z

436

Cascade events at IceCube + DeepCore as a definitive constraint on the dark matter interpretation of the PAMELA and Fermi anomalies  

Science Journals Connector (OSTI)

Dark matter decaying or annihilating into ?+?- or ?+?- has been proposed as an explanation for the e± anomalies reported by PAMELA and Fermi. Recent analyses show that IceCube, supplemented by DeepCore, will be able to significantly constrain the parameter space of decays to ?+?-, and rule out decays to ?+?- and annihilations to ?+?- in less than five years of running. These analyses rely on measuring tracklike events in IceCube + DeepCore from down-going ??. In this paper we show that by instead measuring cascade events, which are induced by all neutrino flavors, IceCube + DeepCore can rule out decays to ?+?- in only three years of running, and rule out decays to ?+?- and annihilation to ?+?- in only one year of running. These constraints are highly robust to the choice of dark matter halo profile and independent of dark matter-nucleon crosssection.

Sourav K. Mandal; Matthew R. Buckley; Katherine Freese; Douglas Spolyar; Hitoshi Murayama

2010-02-02T23:59:59.000Z

437

GAMMA-RAY LOUDNESS, SYNCHROTRON PEAK FREQUENCY, AND PARSEC-SCALE PROPERTIES OF BLAZARS DETECTED BY THE FERMI LARGE AREA TELESCOPE  

SciTech Connect (OSTI)

The parsec-scale radio properties of 232 active galactic nuclei, most of which are blazars, detected by the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope have been observed contemporaneously by the Very Long Baseline Array (VLBA) at 5 GHz. Data from both the first 11 months (1FGL) and the first 2 years (2FGL) of the Fermi mission were used to investigate these sources' {gamma}-ray properties. We use the ratio of the {gamma}-ray-to-radio luminosity as a measure of {gamma}-ray loudness. We investigate the relationship of several radio properties to {gamma}-ray loudness and to the synchrotron peak frequency. There is a tentative correlation between {gamma}-ray loudness and synchrotron peak frequency for BL Lac objects in both 1FGL and 2FGL, and for flat-spectrum radio quasars (FSRQs) in 2FGL. We find that the apparent opening angle tentatively correlates with {gamma}-ray loudness for FSRQs, but only when we use the 2FGL data. We also find that the total VLBA flux density correlates with the synchrotron peak frequency for BL Lac objects and FSRQs. The core brightness temperature also correlates with synchrotron peak frequency, but only for the BL Lac objects. The low-synchrotron-peaked (LSP) BL Lac object sample shows indications of contamination by FSRQs which happen to have undetectable emission lines. There is evidence that the LSP BL Lac objects are more strongly beamed than the rest of the BL Lac object population.

Linford, J. D.; Taylor, G. B.; Schinzel, F. K., E-mail: jlinford@unm.edu [Department of Physics and Astronomy, University of New Mexico, MSC07 4220, Albuquerque, NM 87131-0001 (United States)

2012-09-20T23:59:59.000Z

438

GAMMA-RAY OBSERVATIONS OF THE MICROQUASARS CYGNUS X-1, CYGNUS X-3, GRS 1915+105, AND GX 339–4 WITH THE FERMI LARGE AREA TELESCOPE  

SciTech Connect (OSTI)

Detecting gamma-rays from microquasars is a challenging but worthwhile endeavor for understanding particle acceleration and the jet mechanism and for constraining leptonic/hadronic emission models. We present results from a likelihood analysis on timescales of 1 day and 10 days of ?4 yr worth of gamma-ray observations (0.1-10 GeV) by Fermi-LAT of Cyg X-1, Cyg X-3, GRS 1915+105, and GX 339–4. Our analysis reproduced all but one of the previous gamma-ray outbursts of Cyg X-3 as reported with Fermi or AGILE, plus five new days on which Cyg X-3 is detected at a significance of ?5? that are not reported in the literature. In addition, Cyg X-3 is significantly detected on 10 day timescales outside of known gamma-ray flaring epochs, which suggests that persistent gamma-ray emission from Cyg X-3 has been detected for the first time. For Cyg X-1 we find three low-significance excesses (?3-4?) on daily timescales that are contemporaneous with gamma-ray flares reported (also at low significance) by AGILE. Two other microquasars, GRS 1915+105 and GX 339–4, are not detected, and we derive 3? upper limits of 2.3 × 10{sup –8} photons cm{sup –2} s{sup –1} and 1.6 × 10{sup –8} photons cm{sup –2} s{sup –1}, respectively, on the persistent flux in the 0.1-10 GeV range. These results enable us to define a list of the general conditions that are necessary for the detection of gamma-rays from microquasars.

Bodaghee, Arash; Tomsick, John A. [Space Sciences Laboratory, 7 Gauss Way, University of California, Berkeley, CA 94720 (United States); Pottschmidt, Katja [CRESST and NASA Goddard Space Flight Center, Astrophysics Science Division, Code 661, Greenbelt, MD 20771 (United States); Rodriguez, Jérôme [Laboratoire AIM, CEA/IRFU, Université Paris Diderot, CNRS/INSU, CEA DSM/IRFU/SAp, Centre de Saclay, F-91191 Gif-sur-Yvette (France); Wilms, Jörn [Dr. Karl Remeis-Sternwarte and Erlangen Centre for Astroparticle Physics, Friedrich-Alexander-Universität Erlangen-Nürnberg, Sternwartstrasse 7, D-96049 Bamberg (Germany); Pooley, Guy G., E-mail: bodaghee@ssl.berkeley.edu [Mullard Radio Astronomy Observatory, Cavendish Laboratory, The University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE (United Kingdom)

2013-10-01T23:59:59.000Z

439

X-ray movies reveal insect flight, muscle motion  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

BioCAT BioCAT X-ray movies reveal insect flight, muscle motion Photo credit: Michael Dickinson Watching flies fly may not seem like high-tech science, but for researchers using the Western Hemisphere's most brilliant X-rays, from the Advanced Photon Source located at the U.S. Department of Energy's Argonne National Laboratory, it not only helps explain how insects fly but also may someday aid in understanding human heart function. The researchers, from the Illinois Institute of Technology (IIT), Caltech and the University of Vermont, merged two distinct technologies, intense X-ray beams and electronic flight simulators, to study how insect muscles can generate such extraordinary levels of power. The results are published in the the January 20,. 2005, issue of the journal Nature.

440

Plants' Rapid Response System Revealed | Advanced Photon Source  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Rewriting the Organofluorine Playbook Rewriting the Organofluorine Playbook Computer-Designed Proteins to Disarm a Variety of Flu Viruses Driving Membrane Curvature Unlocking the Nanoscale Secrets of Bird-Feather Colors An Unlikely Route to Ferroelectricity Science Highlights Archives: 2013 | 2012 | 2011 | 2010 2009 | 2008 | 2007 | 2006 2005 | 2004 | 2003 | 2002 2001 | 2000 | 1998 | Subscribe to APS Science Highlights rss feed Plants' Rapid Response System Revealed JULY 6, 2012 Bookmark and Share Images of several related proteins made at synchrotrons in the U.S. and France have allowed scientists at Washington University in St. Louis and the European Molecular Biology Laboratory in Grenoble, France, to solve the structure of a key piece of the biochemical machinery that allows plants to control the concentrations of circulating hormones. WUSTL graduate student

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441

DOE Joint Genome Institute: Genome of Simplest Animal Reveals Ancient  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

21, 2008 21, 2008 Genome of Simplest Animal Reveals Ancient Lineage, Confounding Array of Complex Capabilities WALNUT CREEK, CA-As Aesop said, appearances are deceiving-even in life's tiniest critters. From first detection in the 1880s, clinging to the sides of an aquarium, to its recent characterization by the U.S. Department of Energy Joint Genome Institute (DOE JGI), a simple and primitive animal, Trichoplax adhaerens, appears to harbor a far more complex suite of capabilities than meets the eye. The findings, reported in the August 21 online edition of the journal Nature, establish a group of organisms as a branching point of animal evolution and identify sets of genes, or a "parts list," employed by organisms that have evolved along particular branches.

442

Rechargeable Heat Battery's Secret Revealed: Solar Energy Capture in  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Rechargeable Heat Rechargeable Heat Battery Rechargeable Heat Battery's Secret Revealed Solar energy capture in chemical form makes it storable and transportable January 11, 2011 | Tags: Chemistry, Energy Technologies, Franklin Contact: John Hules, JAHules@lbl.gov, +1 510 486 6008 2011-01-11-Heat-Battery.jpg A molecule of fulvalene diruthenium, seen in diagram, changes its configuration when it absorbs heat, and later releases heat when it snaps back to its original shape. Image: Jeffrey Grossman Broadly speaking, there have been two approaches to capturing the sun's energy: photovoltaics, which turn the sunlight into electricity, or solar-thermal systems, which concentrate the sun's heat and use it to boil water to turn a turbine, or use the heat directly for hot water or home

443

DOE Joint Genome Institute: Soybean Genome Analysis Reveals Pathways for  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

January 13, 2010 January 13, 2010 Soybean Genome Analysis Reveals Pathways for Improving Biodiesel, Disease Resistance, and Reducing Waste Runoff WALNUT CREEK, CA-Soybean, one of the most important global sources of protein and oil, is now the first legume species with a published complete draft genome sequence. The sequence and its analysis appear in the January 14 edition of the journal Nature. The research team comprised 18 institutions, including the U.S. Department of Energy Joint Genome Institute (DOE JGI), the U.S. Department of Agriculture-Agricultural Research Service (USDA-ARS), Purdue University and the University of North Carolina at Charlotte. The DOE, National Science Foundation, USDA and United Soybean Board supported the research. helix made of soybeans

444

T-cadherin structures reveal a novel adhesive binding mechanism  

SciTech Connect (OSTI)

Vertebrate genomes encode 19 classical cadherins and about 100 nonclassical cadherins. Adhesion by classical cadherins depends on binding interactions in their N-terminal EC1 domains, which swap N-terminal {beta}-strands between partner molecules from apposing cells. However, strand-swapping sequence signatures are absent from nonclassical cadherins, raising the question of how these proteins function in adhesion. Here, we show that T-cadherin, a glycosylphosphatidylinositol (GPI)-anchored cadherin, forms dimers through an alternative nonswapped interface near the EC1-EC2 calcium-binding sites. Mutations within this interface ablate the adhesive capacity of T-cadherin. These nonadhesive T-cadherin mutants also lose the ability to regulate neurite outgrowth from T-cadherin-expressing neurons. Our findings reveal the likely molecular architecture of the T-cadherin homophilic interface and its requirement for axon outgrowth regulation. The adhesive binding mode used by T-cadherin may also be used by other nonclassical cadherins

Ciatto, Carlo; Bahna, Fabiana; Zampieri, Niccolò; VanSteenhouse, Harper C.; Katsamba, Phini S; Ahlsen, Goran; Harrison, Oliver J.; Brasch, Julia; Jin, Xiangshu; Posy, Shoshana; Vendome, Jeremie; Ranscht, Barbara; Jessell, Thomas M.; Honig, Barry; Shapiro, Lawrence (Columbia); (Burnham)

2010-03-30T23:59:59.000Z

445

Patterns revealed through weighted networks: A random matrix theory relation  

E-Print Network [OSTI]

Despite the tremendous advancements in the field of network theory, very few studies have taken weights in the interactions into consideration that emerge naturally in all real world systems. Using a weighted social network, we demonstrate the profound impact of weights in interactions on emerging structural properties. The analysis reveals that randomness existing in particular time frame affects the decisions of individuals rendering them more freedom of choice in situations of financial security. While the structural organization of networks remain same throughout all datasets, random matrix theory provides insight into interaction pattern of individual of the society in situations of crisis. It has also been contemplated that individual accountability in terms of weighted interactions remains as a key to success unless segregation of tasks comes into play.

Sarkar, Camellia

2014-01-01T23:59:59.000Z

446

Polymorphism of DNA-anionic Liposome Complexes Reveals Hierarchy of  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Polymorphism of DNA-anionic Polymorphism of DNA-anionic Liposome Complexes Reveals Hierarchy of Ion-mediated Interactions Hongjun Liang,* Daniel Harries,+ and Gerard C. L. Wong* *Department of Materials Science & Engineering, Department of Physics, Department of Bioengineering, University of Illinois at Urbana-Champaign, IL 61801, USA +Laboratory of Physical and Structural Biology, National Institute of Child Health and Human Development, NIH, Bethesda, MD 20892, USA Gene therapy using either viral or synthetic vectors is currently one of the most promising strategies for developing cures for many hereditary and acquired diseases. Protocols have been approved for cancer, hemophilia, cystic fibrosis, neuromuscular disorders, and others. Although synthetic nonviral systems such as cationic liposomes generally transfect less efficiently than viruses, they have a number of advantages such as high DNA packaging capacity and low immunogenicity. Since their introduction in 1987, cationic lipid-DNA complexes (CL-DNA) have emerged as one of the major non-viral DNA delivery platforms. CL-DNA complexes have been used in gene therapy for a broad range of cell types as well as delivery systems for cancer vaccines.

447

Algal genomes reveal evolutionary mosaicism and the fate of nucleomorphs  

SciTech Connect (OSTI)

Cryptophyte and chlorarachniophyte algae are transitional forms in the widespread secondary endosymbiotic acquisition of photosynthesis by engulfment of eukaryotic algae. Unlike most secondary plastid-bearing algae, miniaturized versions of the endosymbiont nuclei (nucleomorphs) persist in cryptophytes and chlorarachniophytes. To determine why, and to address other fundamental questions about eukaryote eukaryote endosymbiosis, we sequenced the nuclear genomes of the cryptophyte Guillardia theta and the chlorarachniophyte Bigelowiella natans. Both genomes have 21,000 protein genes and are intron rich, and B. natans exhibits unprecedented alternative splicing for a single-celled organism. Phylogenomic analyses and subcellular targeting predictions reveal extensive genetic and biochemical mosaicism, with both host- and endosymbiont-derived genes servicing the mitochondrion, the host cell cytosol, the plastid and the remnant endosymbiont cytosol of both algae. Mitochondrion-to-nucleus gene transfer still occurs in both organisms but plastid-to-nucleus and nucleomorph-to-nucleus transfers do not, which explains why a small residue of essential genes remains locked in each nucleomorph.

Curtis, Bruce A.; Tanifuji, Goro; Burki, Fabien; Gruber, Ansgar; Irimia, Manuuel; Maruyama, Shinichiro; Arias, Maria C.; Ball, Steven G.; Gile, Gillian H.; Hirakawa, Yoshihisa; Hopkins, Julia F.; Kuo, Alan; Rensing, Stefan A.; Schmutz, Jeremy; Symeonidi, Aikaterini; Elias, Marek; Eveleigh, Robert J. M.; Herman, Emily K.; Klute, Mary J.; Nakayama, Takuro; Obornik, Miroslav; Reyes-Prieto, Adrian; Armbrust, E. Virginia; Aves, Stephen J.; Beiko, Robert G.; Coutinho, Pedro; Dacks, Joel B.; Durnford, Dion G.; Fast, Naomi M.; Green, Beverley R.; Grisdale, Cameron J.; Hempel, Franziska; Henrissat, Bernard; Hoppner, Marc P.; Ishida, Ken-Ichiro; Kim, Eunsoo; Koreny, Ludek; Kroth, Peter G.; Liu, Yuan; Malik, Shehre-Banoo; Maier, Uwe G.; McRose, Darcy; Mock, Thomas; Neilson, Jonathan A. D.; Onodera, Naoko T.; Poole, Anthony M.; Pritham, Ellen J.; Richards, Thomas A.; Rocap, Gabrielle; Roy, Scott W.; Sarai, Chihiro; Schaack, Sarah; Shirato, Shu; Slamovits, Claudio H.; Spencer, Davie F.; Suzuki, Shigekatsu; Worden, Alexandra Z.; Zauner, Stefan; Barry, Kerrie; Bell, Callum; Bharti, Arvind K.; Crow, John A.; Grimwood, Jane; Kramer, Robin; Lindquist, Erika; Lucas, Susan; Salamov, Asaf; McFadden, Geoffrey I.; Lane, Christopher E.; Keeling, Patrick J.; Gray, Michael W.; Grigoriev, Igor V.; Archibald, John M.

2012-08-10T23:59:59.000Z

448

Cost-effective treatment looks at entire production system  

SciTech Connect (OSTI)

The determination of cost-effectiveness is best undertaken after the most advantageous approach to solving the problem is selected. Focusing the approach on the injection well could result in the addition of corrosion inhibitor, paraffin inhibitor, biocide and scale inhibitor, with the possible incorporation of a flotation system and a filter. Alternatively, the approach can focus on treating the problem at the battery. The approach highlighted in this paper focuses on the initial effort on defining and solving the problems occurring at the producing well. Field histories of such programs carried out in the Persian Basin illustrate that this approach reduced the battery workload. The next phase focuses on solving problems that originate at the battery to reduce the injection well load.

Evans, S. (Conoco Inc., Houston, TX (US))

1990-01-01T23:59:59.000Z

449

UNSCOM faces entirely new verification challenges in Iraq  

SciTech Connect (OSTI)

Starting with the very first declarations and inspections, it became evident that Iraq was not acting in good faith, would use every possible pretext to reinterpret UNSCOM's inspection rights, and occasionally would use harassment tactics to make inspections as difficult as possible. Topics considered in detail include; initial assumptions, outstanding issues, and UNSCOM's future attitude.

Trevan, T.

1993-04-01T23:59:59.000Z

450

GROWTH CONDITIONS FOR ENTIRE FUNCTIONS WITH ONLY BOUNDED FATOU COMPONENTS  

E-Print Network [OSTI]

this conclusion, and showed that the best one can hope for is that the growth of f does not exceed order 1 time where the notation m(r, f) is used in that meaning. The order (f) and lower order (f) of f small. The function f(z) = z-1/2 sin z + z + a is of order 1/2, mean type, and if a is a sufficiently

Hinkkanen, Aimo

451

Structures of GRP94-Nucleotide Complexes Reveal Mechanistic Differences  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Structures of GRP94-Nucleotide Structures of GRP94-Nucleotide Complexes Reveal Mechanistic Differences between the Hsp90 Chaperones Life depends on the biochemical activity of the thousands of proteins that inhabit and decorate the surface of every one of our cells. Proteins themselves, although simple linear combinations of the twenty amino acids, derive their remarkable properties from the complex three-dimensional structures into which they fold. In this way, enzyme active sites are created, protein-protein recognition surfaces are formed, and the chemistry of life is set in motion. Although in principle the precise three-dimensional structure for each protein is encoded in its linear chain of amino acids, in practice it is often difficult or impossible for a protein to achieve this final fold on its own in the context of a cellular environment that is packed to the gills with millions of other proteins, nucleic acids, carbohydrates, lipids, and other small molecules. As a result, cells have evolved a corps of proteins known as molecular chaperones that assist newly synthesized proteins as they adopt their active fold. One such family of chaperones is known as the hsp90 family (Pratt and Toft, 2003). "Client" proteins of the hsp90 family are diverse, and their functions range from signal transduction to immune response. Specific inhibitors of hsp90 chaperones exhibit potent anti-tumor activity (Chiosis et al., 2006; Sharp and Workman, 2006), showing that preventing the proper folding of client proteins, many of which are implicated in cancer, can have profound therapeutic implications.

452

E-Print Network 3.0 - allosteric sites revealed Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

sites revealed Page: << < 1 2 3 4 5 > >> 1 Searching for new allosteric sites in enzymes Jeanne A Hardy and James A Wells Summary: revealed several new allosteric sites that...

453

Functional Connectivity Magnetic Resonance Imaging Reveals Cortical Functional Connectivity in the Developing Brain  

E-Print Network [OSTI]

in the Developing Brain Weili Lin, Ph.D.^1 , Quan Zhu, M.S.^ 2 , Wei Gao, M.S.^ 3 , Yasheng Chen, D.Sc.^ 1 , Cheng was utilized to depict brain regions exhibiting temporal synchronization, also known as resting brain pixel-by-pixel throughout the entire brain, identifying regions with high temporal correlation. Results

Utah, University of

454

SKA SA test telescope reveals binary star system South Africa's test telescope reveals secrets of a binary star system and proves the country is able to  

E-Print Network [OSTI]

SKA SA test telescope reveals binary star system South Africa's test telescope reveals secrets, has created huge research and job opportunities. South Africa's Karoo Array Telescope (KAT-7) has at the SKA South Africa. The 64-dish MeerKAT ­ which SKA South Africa director Bernie Fanaroff once described

Jarrett, Thomas H.

455

DOE/EA-1570: Final Environmental Assessment for Construction and Operation of Neutrinos at the Main Injector Off-Axis Electron Neutrino Appearance Experiment at the Fermi National Accelerator Laboratory, Batavia, Illinois, and St. Louis County, Minnesota  

Broader source: Energy.gov (indexed) [DOE]

70 70 FINAL ENVIRONMENTAL ASSESSMENT Environmental Assessment for Construction and Operation of Neutrinos at the Main Injector Off-Axis Electron Neutrino (ν e ) Appearance Experiment (NOvA) at the Fermi National Accelerator Laboratory, Batavia, Illinois, and St. Louis County, Minnesota U.S. Department of Energy, Lead Agency Fermi Site Office Batavia, IL U.S. Army Corps of Engineers, Cooperating Agency St. Paul District St. Paul, MN June 2008 (DOE/EA-1570) NOvA Environmental Assessment June 2008 ii DISCLAIMER Reference herein to any specific commercial product, process or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any

456

Comment on "A limit on the variation of the speed of light arising from quantum gravity effects" aka "Testing Einstein's special relativity with Fermi's short hard gamma-ray burst GRB090510"  

E-Print Network [OSTI]

Recently the Fermi GBM and LAT Collaborations reported their new observational data disfavoring quite a number of the quantum gravity theories, including the one suggesting the nonlinear (logarithmic) modification of a quantum wave equation. We show that the latter is still far from being ruled out: it is not only able to explain the new data but also its phenomenological implications turn out to be more vast (and more interesting) than one expected before.

Konstantin G. Zloshchastiev

2009-11-30T23:59:59.000Z

457

Nonthermal Two Component Dark Matter Model for Fermi-LAT $\\gamma$-ray excess and 3.55 keV X-ray Line  

E-Print Network [OSTI]

A two component model of nonthermal dark matter is formulated to simultaneously explain the Fermi-LAT results indicating a $\\gamma$-ray excess observed from our Galactic Centre in the 1-3 GeV energy range and the detection of an X-ray line at 3.55 keV from extra galactic sources. Two additional Standard Model singlet scalar fields $S_2$ and $S_3$ are introduced. These fields couple among themselves and with the Standard Model Higgs doublet $H$. The interaction terms among the scalar fields, namely $H$, $S_2$ and $S_3$, are constrained by the application of a discrete $\\mathbb{Z}_2\\times \\mathbb{Z}^\\prime_2$ symmetry which breaks softly to a remnant $\\mathbb{Z}^{\\prime \\prime}_2$ symmetry. This residual discrete symmetry is then spontaneously broken through an MeV order vacuum expectation value $u$ of the singlet scalar field $S_3$. The resultant physical scalar spectrum has the Standard Model like Higgs as $\\chi_{{}_{{}_1}}$ with $M_{\\chi_{{}_{{}_1}}}\\sim 125$ GeV, a moderately heavy scalar $\\chi_{{}_{{}_2}}$...

Biswas, Anirban; Roy, Probir

2015-01-01T23:59:59.000Z

458

GeV Gamma-ray Emission Detected by Fermi-LAT Likely Associated with the Supernova Remnant Kesteven 41 in a Molecular Environment  

E-Print Network [OSTI]

Hadronic emission from supernova remnant (SNR)--molecular cloud (MC) association systems has been widely regarded as a probe of the shock accelerated cosmic protons. We here report on the detection of a $\\gamma$-ray emission source, with a significance of $24\\sigma$ in 0.2--300 GeV, projectively on the northwest of SNR Kesteven 41, using 5.6 yr Fermi-LAT observation data. The $3\\sigma$ error circle, 0.09 degree in radius, covers the 1720MHz OH maser and is essentially consistent with the location of the $V_{LSR}~-50 km/s $ MC with which the SNR interacts. The source emission has a power-law spectrum with a photon index $2.38\\pm0.03$ and a 0.2--300 GeV luminosity $~1.6*10^{36} erg /s$ at a distance 12 kpc. There is no radio pulsar in the $3\\sigma$ circle responsible for the high luminosity. While the inverse Compton scattering scenario would lead to a difficulty in the electron energy budget, the source emission can be naturally explained with the hadronic interaction between the relativistic protons accelerat...

Liu, Bing; Zhang, Xiao; Zhang, Gao-Yuan; Xing, Yi

2015-01-01T23:59:59.000Z