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Sample records for fermi energy ef

  1. Energy Ef cient Routing With Unreliable Links in Wireless Networks

    E-Print Network [OSTI]

    Li, Xiang-Yang

    Energy Ef cient Routing With Unreliable Links in Wireless Networks Xiang-Yang Li Dept. of Compt24@iit.edu Abstract Energy ef cient routings and power control tech- niques in wireless networks have wireless link layers by integrating the power control techniques into the energy ef cient routing. We study

  2. Progress from DOE EF RC: Solid-State Solar-Thermal Energy Conversion...

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

    from DOE EF RC: Solid-State Solar-Thermal Energy Conversion Center (S3TEC ) Progress from DOE EF RC: Solid-State Solar-Thermal Energy Conversion Center (S3TEC ) Introduction to the...

  3. 6437r 2010 American Chemical Society pubs.acs.org/EF Energy Fuels 2010, 24, 64376441 : DOI:10.1021/ef1012837

    E-Print Network [OSTI]

    Gülder, Ömer L.

    6437r 2010 American Chemical Society pubs.acs.org/EF Energy Fuels 2010, 24, 6437­6441 : DOI:10.1021/ef1012837 Published on Web 11/16/2010 Spectroscopic Study of Aviation Jet Fuel Thermal Oxidative September 21, 2010 Aviation fuel is used as a coolant to remove waste heat loads from an aircraft

  4. 4470r 2009 American Chemical Society pubs.acs.org/EF Energy Fuels 2009, 23, 44704478 : DOI:10.1021/ef900107b

    E-Print Network [OSTI]

    Pan, Ning

    4470r 2009 American Chemical Society pubs.acs.org/EF Energy Fuels 2009, 23, 4470­4478 : DOI:10 of Engineering Mechanics, Tsinghua University, Beijing 100084, China, Earth and Environmental Sciences Division transfer and, thus, for energy conservation. In this paper, we investigated the influence of viscosity

  5. 3589r 2010 American Chemical Society pubs.acs.org/EF Energy Fuels 2010, 24, 35893594 : DOI:10.1021/ef100402g

    E-Print Network [OSTI]

    Zare, Richard N.

    3589r 2010 American Chemical Society pubs.acs.org/EF Energy Fuels 2010, 24, 3589­3594 : DOI:10 contain heteroatoms. An alternative proposed architecture is the "island" model,11,12 which consists/ionization experiments. Energy Fuels 2007, 21 (5), 2863­2868. (2) Hortal

  6. 3510r 2010 American Chemical Society pubs.acs.org/EF Energy Fuels 2010, 24, 35103516 : DOI:10.1021/ef100249w

    E-Print Network [OSTI]

    Lee, Tonghun

    3510r 2010 American Chemical Society pubs.acs.org/EF Energy Fuels 2010, 24, 3510­3516 : DOI:10 the numerical optimization of a multi-step ignition model to predict the auto-ignition of dimethyl ether (DME of new oxygenated fuel blends, where detailed or reduced mechanisms are not available. Experimental data

  7. Fermi Feud | Department of Energy

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of Natural GasAdjustmentsShirleyEnergy A plug-inPPLforLDRD Report to CongressApril 6, 2012

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

    E-Print Network [OSTI]

    Luryi, Serge

    Aviv 69978, Israel S. Luryi State University of New York, Stony Brook, New York 11794-2350 H. Shtrikman if the barrier height is known . In this letter, a new method is proposed for the Fermi energy determinationA method for Fermi energy measurements A. Tsukernik,a) M. Slutzky, and A. Palevski School

  9. Fermi Observations of High-Energy Gamma-Ray Emission from GRB 080916C

    E-Print Network [OSTI]

    Moskalenko, Igor V.

    2008, Fermi observed the exceptionally luminous GRB 080916C, with the largest apparent energy releaseFermi Observations of High-Energy Gamma-Ray Emission from GRB 080916C The Fermi LAT and Fermi GBM together record GRBs over a broad energy range spanning about 7 decades of gamma- ray energy. In September

  10. Energy Cost to Make a Hole in the Fermi Sea

    E-Print Network [OSTI]

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

    2011-04-13

    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.

  11. Dynamical description of heavy-ion collisions at Fermi energies

    E-Print Network [OSTI]

    Napolitani, P

    2015-01-01

    Descriptions of heavy-ion collisions at Fermi energies require to take into account in-medium dissipation and phase-space fluctuations. The interplay of these correlations with the one-body collective behaviour determines the properties (kinematics and fragment production) and the variety of mechanisms (from fusion to neck formation and multifragmentation) of the exit channel. Starting from fundamental concepts tested on nuclear matter, we build up a microscopic description which addresses finite systems and applies to experimental observables.

  12. Published: April 19, 2011 r 2011 American Chemical Society 2142 dx.doi.org/10.1021/ef2002102 |Energy Fuels 2011, 25, 21422150

    E-Print Network [OSTI]

    Gülder, Ömer L.

    |Energy Fuels 2011, 25, 2142­2150 ARTICLE pubs.acs.org/EF Analysis of Aviation Fuel Thermal Oxidative, Toronto, Ontario M3H 5T6, Canada ABSTRACT: In modern gas-turbine aircraft, aviation fuel is routinely used, in addition to its conventional role as the energy source through combustion. The increase of the fuel

  13. Enrico Fermi Award Ceremony | Department of Energy

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of Natural GasAdjustmentsShirleyEnergy A plug-inPPLfor Innovative SolarSavingsAugust 26,246April|Remarks Prepared for

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

    E-Print Network [OSTI]

    Boyer, Edmond

    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

  15. Finite-size energy of non-interacting Fermi gases

    E-Print Network [OSTI]

    Martin Gebert

    2014-06-14

    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.

  16. Fermi Observations of High-Energy Gamma-Ray Emission From GRB...

    Office of Scientific and Technical Information (OSTI)

    From GRB 080825C Citation Details In-Document Search Title: Fermi Observations of High-Energy Gamma-Ray Emission From GRB 080825C Authors: Abdo, A.A. ; Naval Research Lab,...

  17. Fermi Observations of High-Energy Gamma-Ray Emission from GRB...

    Office of Scientific and Technical Information (OSTI)

    from GRB 080916C Citation Details In-Document Search Title: Fermi Observations of High-Energy Gamma-Ray Emission from GRB 080916C Authors: Abdo, Aous A. ; Naval Research...

  18. Estimating the energy of stitching together the Maxwell and Fermi neutron spectra

    SciTech Connect (OSTI)

    Ionov, V. S., E-mail: ivs2010@vver.kiae.ru; Marin, S. V. [National Research Center Kurchatov Institute (Russian Federation)

    2014-12-15

    The energy of stitching together the Maxwell and Fermi spectra is estimated on the basis of experimental data and the results of calculations carried out using the MCU-RFFI and MCU-5 codes.

  19. Reaction Dynamics and Multifragmentation in Fermi Energy Heavy Ion Reactions

    E-Print Network [OSTI]

    R. Wada; T. Keutgen; K. Hagel; Y. G. Ma; J. Wang; M. Murray; L. Qin; P. Smith; J. B. Natowitz; R. Alfarro; J. Cibor; M. Cinausero; Y. El Masri; D. Fabris; E. Fioretto; A. Keksis; M. Lunardon; A. Makeev; N. Marie; E. Martin; A. Martinez-Davalos; A. Menchaca-Rocha; G. Nebbia; G. Prete; V. Rizzi; A. Ruangma; D. V. Shetty; G. Souliotis; P. Staszel; M. Veselsky; G. Viesti; E. M. Winchester; S. J. Yennello; Z. Majka; A. Ono

    2003-08-27

    The reaction systems, 64Zn + 58Ni, 64Zn + 92Mo, 64Zn + 197Au, at 26A, 35A and 47A MeV, have been studied both in experiments with a 4$\\pi$ detector array, NIMROD, and with Antisymmetrized Molecular Dynamics model calculations employing effective interactions corresponding to soft and stiff equations of state (EOS). Direct experimental observables, such as multiplicity distributions, charge distributions, energy spectra and velocity spectra, have been compared in detail with those of the calculations and a reasonable agreement is obtained. The velocity distributions of $\\alpha$ particles and fragments with Z >= 3 show distinct differences in calculations with the soft EOS and the stiff EOS. The velocity distributions of $\\alpha$ particle and Intermediate Mass Fragments (IMF's) are best described by the stiff EOS. Neither of the above direct observables nor the strength of the elliptic flow are sensitive to changes in the in-medium nucleon-nucleon (NN) cross sections. A detailed analysis of the central collision events calculated with the stiff EOS revealed that multifragmentation with cold fragment emission is a common feature predicted for all reactions studied here. A possible multifragmentation scenario is presented; after the preequilibrium emission ceases in the composite system, cold light fragments are formed in a hotter gas of nucleons and stay cold until the composite system underdoes multifragmentation. For reaction with 197Au at 47A MeV a significant radial expansion takes place. For reactions with 58Ni and 92Mo at 47A MeV semi-transparency becomes prominent. The differing reaction dynamics drastically change the kinematic characteristics of emitted fragments. This scenario gives consistent explanations for many existing experimental results in the Fermi energy domain.

  20. Nuclear symmetry energy from the Fermi-energy difference in nuclei

    E-Print Network [OSTI]

    Ning Wang; Li Ou; Min Liu

    2013-03-15

    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.

  1. Data:Ae3cd3b5-369c-4ef5-a089-9be6f92e16fa | Open Energy Information

    Open Energy Info (EERE)

    ef5-a089-9be6f92e16fa No revision has been approved for this page. It is currently under review by our subject matter experts. Jump to: navigation, search Loading... 1. Basic...

  2. EFS Appendix SFA-1

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration would like submit theCovalentLaboratory |SectorforOXFORD| EnergyAntenna Research Mark5,

  3. EFS Appendix SFA-1

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration would like submit theCovalentLaboratory |SectorforOXFORD| EnergyAntenna Research Mark5,,

  4. U.S. Department of Energy Fermi National Accelerator Laboratory |

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious RankADVANCEDInstallers/ContractorsPhotovoltaicsStateof Energy| DepartmentFuelDecember 11, 2008Agenda,

  5. Superallowed Fermi transitions in RPA with a relativistic point-coupling energy functional

    E-Print Network [OSTI]

    Z. X. Li; J. M. Yao; H. Chen

    2011-04-11

    The self-consistent random phase approximation (RPA) approach with the residual interaction derived from a relativistic point-coupling energy functional is applied to evaluate the isospin symmetry-breaking corrections {\\delta}c for the 0+\\to0+ superallowed Fermi transitions. With these {\\delta}c values, together with the available experimental ft values and the improved radiative corrections, the unitarity of the Cabibbo-Kobayashi-Maskawa (CKM) matrix is examined. Even with the consideration of uncertainty, the sum of squared top-row elements has been shown to deviate from the unitarity condition by 0.1% for all the employed relativistic energy functionals.

  6. Published: June 14, 2011 r 2011 American Chemical Society 2896 dx.doi.org/10.1021/ef2005332 |Energy Fuels 2011, 25, 28962908

    E-Print Network [OSTI]

    Lee, Tonghun

    be addressed by displa- cing fossil fuels with alternative fuels. The long-term successful replacement Fuels 2011, 25, 2896­2908 ARTICLE pubs.acs.org/EF Ignition Characteristics of Diesel and Canola, whereby a given temperature is attained prior to the fuel spray by altering the charge cooling time after

  7. Neutrino-nucleus interactions at low energies within Fermi-liquid theory

    E-Print Network [OSTI]

    Gennady I. Lykasov; Vadim A. Bednyakov

    2007-03-13

    Cross sections are calculated for neutrino scattering off heavy nuclei at energies below 50 MeV. The theory of Fermi liquid is applied to estimate the rate of neutrino-nucleon elastic and inelastic scattering in a nuclear medium in terms of dynamic form factors. The cross sections, obtained here in a rather simple way, are in agreement with the results of the other much more sophisticated nuclear models. A background rate from the solar neutrino interactions within a large Ge detector is estimated in the above-mentioned approach. The knowledge of the rate is in particular rather important for new-generation large-scale neutrino experiments.

  8. Production of cold fragments in nucleus-nucleus collisions in the Fermi-energy domain

    E-Print Network [OSTI]

    M. Veselsky; G. A. Souliotis

    2006-11-06

    The reaction mechanism of nucleus-nucleus collisions at projectile energies around the Fermi energy is investigated with emphasis on the production of fragmentation-like residues. The results of simulations are compared to experimental mass distributions of elements with Z = 21 - 29 observed in the reactions 86Kr+124,112Sn at 25 AMeV. The model of incomplete fusion is modified and a component of excitation energy of the cold fragment dependent on isospin asymmetry is introduced. The modifications in the model of incomplete fusion appear consistent with both overall model framework and available experimental data. A prediction is provided for the production of very neutron-rich nuclei using a secondary beam of 132Sn where e.g. the reaction 132Sn+238U at 28 AMeV appears as a possible alternative to the use of fragmentation reactions at higher energies.

  9. Particle and Energy Transport in quantum disordered and quasi-periodic chains connected to mesoscopic Fermi reservoirs

    E-Print Network [OSTI]

    S. Ajisaka; F. Barra; C. Mejia-Monasterio; T. Prosen

    2012-05-06

    We study a model of nonequilibrium quantum transport of particles and energy in a many-body system connected to mesoscopic Fermi reservoirs (the so-called meso-reservoirs). We discuss the conservation laws of particles and energy within our setup as well as the transport properties of quasi-periodic and disordered chains.

  10. Energy transport and correlation between two attractors connected by Fermi-Pasta-Ulam chain

    E-Print Network [OSTI]

    Alexander Fillipov; Bambi Hu; Baowen Li; Alexander Zeltser

    1998-02-12

    We study numerically time evolution of a system which consists of two attractors connected by Fermi-Pasta-Ulam (FPU) chain. It is found that after sufficiently long time there exits self-consistent large scale structure in the system. The wavelet transform is used to separate the modes in different scales. We found that the nonlinear long wavelength mode propagating along the chain assists the energy transport. Further, all points in the system are found to be correlated. Our results explain satisfactorily why the chaotic behaviour is not enough to ensure the Fourier heat law and the thermal conductivity diverges as it is found recently by Lepri et al (PRL 78, 1897(1997).).

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

    SciTech Connect (OSTI)

    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

    2012-08-01

    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.

  12. In-Flight Measurement of the Absolute Energy Scale of the Fermi Large Area Telescope

    SciTech Connect (OSTI)

    Ackermann, M.; /Stanford U., HEPL /SLAC /KIPAC, Menlo Park; Ajello, M.; /Stanford U., HEPL /SLAC /KIPAC, Menlo Park; Allafort, A.; /Stanford U., HEPL /SLAC /KIPAC, Menlo Park; Atwood, W.B.; /UC, Santa Cruz; Axelsson, M.; /Stockholm U. /Stockholm U., OKC /Royal Inst. Tech., Stockholm; Baldini, L.; /INFN, Pisa; Barbiellini, G.; /INFN, Trieste /Trieste U.; Bastieri, D.; /INFN, Padua /Padua U.; Bechtol, K.; /Stanford U., HEPL /SLAC /KIPAC, Menlo Park; Bellazzini, R.; /INFN, Pisa; Berenji, B.; /Stanford U., HEPL /SLAC /KIPAC, Menlo Park; Bloom, E.D.; /Stanford U., HEPL /SLAC /KIPAC, Menlo Park; Bonamente, E.; /INFN, Perugia /Perugia U.; Borgland, A.W.; /Stanford U., HEPL /SLAC /KIPAC, Menlo Park; Bouvier, A.; /UC, Santa Cruz; Bregeon, J.; /INFN, Pisa; Brez, A.; /INFN, Pisa; Brigida, M.; /Bari Polytechnic /INFN, Bari; Bruel, P.; /Ecole Polytechnique; Buehler, R.; /Stanford U., HEPL /SLAC /KIPAC, Menlo Park; Buson, S.; /INFN, Padua /Padua U. /CSIC, Catalunya /Stanford U., HEPL /SLAC /KIPAC, Menlo Park /IASF, Milan /DAPNIA, Saclay /INFN, Perugia /Perugia U. /Stanford U., HEPL /SLAC /KIPAC, Menlo Park /Unlisted, US /Stanford U., HEPL /SLAC /KIPAC, Menlo Park /ASDC, Frascati /Perugia U. /Stanford U., HEPL /SLAC /KIPAC, Menlo Park /Montpellier U. /ASDC, Frascati /Bari Polytechnic /INFN, Bari /Naval Research Lab, Wash., D.C. /Stanford U., HEPL /SLAC /KIPAC, Menlo Park /Stanford U., HEPL /SLAC /KIPAC, Menlo Park /Stanford U., HEPL /SLAC /KIPAC, Menlo Park /Stanford U., HEPL /SLAC /KIPAC, Menlo Park /Stanford U., HEPL /SLAC /KIPAC, Menlo Park /Stanford U., HEPL /SLAC /KIPAC, Menlo Park /Montpellier U. /Bari Polytechnic /INFN, Bari /Ecole Polytechnique /Stanford U., HEPL /SLAC /KIPAC, Menlo Park /Ecole Polytechnique /Hiroshima U. /Stanford U., HEPL /SLAC /KIPAC, Menlo Park /Bari Polytechnic /INFN, Bari /INFN, Bari /NASA, Goddard /INFN, Perugia /Perugia U.; /more authors..

    2012-09-20

    The Large Area Telescope (LAT) on-board the Fermi Gamma-ray Space Telescope is a pair-conversion telescope designed to survey the gamma-ray sky from 20 MeV to several hundreds of GeV. In this energy band there are no astronomical sources with sufficiently well known and sharp spectral features to allow an absolute calibration of the LAT energy scale. However, the geomagnetic cutoff in the cosmic ray electron-plus-positron (CRE) spectrum in low Earth orbit does provide such a spectral feature. The energy and spectral shape of this cutoff can be calculated with the aid of a numerical code tracing charged particles in the Earth's magnetic field. By comparing the cutoff value with that measured by the LAT in different geomagnetic positions, we have obtained several calibration points between {approx}6 and {approx}13 GeV with an estimated uncertainty of {approx}2%. An energy calibration with such high accuracy reduces the systematic uncertainty in LAT measurements of, for example, the spectral cutoff in the emission from gamma ray pulsars.

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

    E-Print Network [OSTI]

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

    2010-10-07

    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.

  14. Remembering Fermi

    SciTech Connect (OSTI)

    Cronin, James (Enrico Fermi Institute, University of Chicago) [Enrico Fermi Institute, University of Chicago

    2005-03-30

    A combination of the discovery of nuclear fission and the circumstances of the 2nd World War brought Enrico Fermi to Chicago, where he led the team that produced the first controlled, self-sustained nuclear chain reaction. Following the war in 1945 Chancellor Hutchins, William Zachariasen, and Walter Bartky convinced Fermi to accept a professorship at the University of Chicago, where the Institute for Nuclear Studies was established. Fermi served as the leading figure in surely the greatest collection of scientists the world has ever seen. Fermi's tenure at Chicago was cut short by his death in 1954. My talk will concentrate on the years 1945-54. Examples of his research notebooks, his speeches, his teaching, and his correspondence will be discussed.

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

    E-Print Network [OSTI]

    Zholents, Alexander A

    2008-01-01

    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

  16. Isospin transport in 84Kr+112,124Sn reactions at Fermi energies

    E-Print Network [OSTI]

    S. Piantelli; G. Casini; A. Olmi; S. Barlini; M. Bini; S. Carboni; P. R. Maurenzig; G. Pasquali; G. Poggi; A. A. Stefanini; R. Bougault; N. LeNeindre; O. Lopez; M. Parlog; E. Vient; E. Bonnet; A. Chbihi; J. D. Frankland; D. Gruyer; E. Rosato; G. Spadaccini; M. Vigilante; B. Borderie; M. F. Rivet; M. Bruno; L. Morelli; M. Cinausero; M. Degerlier; F. Gramegna; T. Marchi; R. Alba; C. Maiolino; D. Santonocito; T. Kozik; T. Twarog

    2013-09-06

    Isospin transport phenomena in dissipative heavy ion collisions have been investigated at Fermi energies with a beam of 84Kr at 35AMeV. A comparison of the /Z of light and medium products forward-emitted in the centre of mass frame when the beam impinges on a n-poor 112Sn and a n-rich 124Sn targets is presented. Data were collected by means of a three-layer telescope with very good performances in terms of mass identification (full isotopic resolution up to Z about 20 for ions punching through the first detector layer) built by the FAZIA Collaboration and located just beyond the grazing angle for both reactions. The /Z of the decay products emitted when the n-rich target is used is always higher than that associated to the n-poor one. Since the detector was able to measure only fragments coming from the QuasiProjectile decay and/or neck emission, the observed behaviour can be ascribed to the isospin diffusion, driven by the isospin gradient between QuasiProjectile and QuasiTarget. Moreover, for light fragments the /Z as a function of the lab velocity of the fragment increases when we move from the QuasiProjectile velocity to the centre of mass (neck zone). This effect can be interpreted as an evidence of isospin drift driven by the density gradient between the QuasiProjectile zone (at normal density) and the more diluted neck zone.

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

    SciTech Connect (OSTI)

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

    2012-05-01

    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.

  18. Fermi at Los Alamos and the early Britain's way to nuclear energy

    E-Print Network [OSTI]

    S. Esposito

    2008-05-02

    A novel recovery of some important documents related to the Fermi course on neutron physics, held at Los Alamos in 1945, is announced. Its relevance for the effective launch of a British nuclear programme in the early postwar period, independently of the U.S. technical cooperation (precluded by the American authorities) and warmly supported by Chadwick, is discussed.

  19. Fermi Bubbles with HAWC

    E-Print Network [OSTI]

    Solares, H A Ayala; Hüntemeyer, P

    2015-01-01

    The Fermi Bubbles, which comprise two large and homogeneous regions of spectrally hard gamma-ray emission extending up to $55^{o}$ above and below the Galactic Center, were first noticed in GeV gamma-ray data from the Fermi Telescope in 2010. The mechanism or mechanisms which produce the observed hard spectrum are not understood. Although both hadronic and lep- tonic models can describe the spectrum of the bubbles, the leptonic model can also explain similar structures observed in microwave data from the WMAP and Planck satellites. Recent publications show that the spectrum of the Fermi Bubbles is well described by a power law with an exponential cutoff in the energy range of 100MeV to 500GeV. Observing the Fermi Bubbles at higher gamma-ray energies will help constrain the origin of the bubbles. A steeper cutoff will favor a leptonic model. The High Altitude Water Cherenkov (HAWC) Observatory, located 4100m above sea level in Mexico, is designed to measure high-energy gamma rays between 100GeV to 100TeV. With...

  20. Fermi level stabilization and band edge energies in Cd{sub x}Zn{sub 1?x}O alloys

    SciTech Connect (OSTI)

    Detert, Douglas M.; Tom, Kyle B.; Dubon, Oscar D. [Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Department of Materials Science and Engineering, University of California, Berkeley, California 94720 (United States); Battaglia, Corsin; Javey, Ali [Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, California 94720 (United States); Denlinger, Jonathan D. [Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Lim, Sunnie H. N. [Environmental Energy Technologies Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Anders, André [Accelerator and Fusion Research Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Yu, Kin M.; Walukiewicz, Wladek [Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

    2014-06-21

    We have measured the band edge energies of Cd{sub x}Zn{sub 1?x}O thin films as a function of composition by three independent techniques: we determine the Fermi level stabilization energy by pinning the Fermi level with ion irradiation, measure the binding energy of valence band states and core levels by X-ray photoelectron spectroscopy, and probe shifts in the conduction band and valence band density of states using soft X-ray absorption and emission spectroscopy, respectively. The three techniques find consensus in explaining the origin of compositional trends in the optical-bandgap narrowing upon Cd incorporation in wurtzite ZnO and widening upon Zn incorporation in rocksalt CdO. The conduction band minimum is found to be stationary for both wurtzite and rocksalt alloys, and a significant upward rise of the valence band maximum accounts for the majority of these observed bandgap changes. Given these band alignments, alloy disorder scattering is found to play a negligible role in decreasing the electron mobility for all alloys. These band alignment details, combined with the unique optical and electrical properties of the two phase regimes, make CdZnO alloys attractive candidates for photoelectrochemical water splitting applications.

  1. Leaky Fermi accelerators

    E-Print Network [OSTI]

    Shah, Kushal; Rom-Kedar, Vered; Turaev, Dmitry

    2015-01-01

    A Fermi accelerator is a billiard with oscillating walls. A leaky accelerator interacts with an environment of an ideal gas at equilibrium by exchange of particles through a small hole on its boundary. Such interaction may heat the gas: we estimate the net energy flow through the hole under the assumption that the particles inside the billiard do not collide with each other and remain in the accelerator for sufficiently long time. The heat production is found to depend strongly on the type of the Fermi accelerator. An ergodic accelerator, i.e. one which has a single ergodic component, produces a weaker energy flow than a multi-component accelerator. Specifically, in the ergodic case the energy gain is independent of the hole size, whereas in the multi-component case the energy flow may be significantly increased by shrinking the hole size.

  2. Leaky Fermi accelerators

    E-Print Network [OSTI]

    Kushal Shah; Vassili Gelfreich; Vered Rom-Kedar; Dmitry Turaev

    2015-04-03

    A Fermi accelerator is a billiard with oscillating walls. A leaky accelerator interacts with an environment of an ideal gas at equilibrium by exchange of particles through a small hole on its boundary. Such interaction may heat the gas: we estimate the net energy flow through the hole under the assumption that the particles inside the billiard do not collide with each other and remain in the accelerator for sufficiently long time. The heat production is found to depend strongly on the type of the Fermi accelerator. An ergodic accelerator, i.e. one which has a single ergodic component, produces a weaker energy flow than a multi-component accelerator. Specifically, in the ergodic case the energy gain is independent of the hole size, whereas in the multi-component case the energy flow may be significantly increased by shrinking the hole size.

  3. A multi-messenger study of the Fermi Bubbles: very high energy gamma rays and neutrinos

    E-Print Network [OSTI]

    Lunardini, Cecilia; Yang, Lili

    2015-01-01

    The Fermi Bubbles have been imaged in sub-TeV gamma rays at Fermi-LAT, and, if their origin is hadronic, they might have been seen with low statistics in $\\sim 0.1- 1$ PeV neutrinos at IceCube. We discuss the detectability of these objects at the new High Altitude Water Cherenkov (HAWC) gamma ray detector. HAWC will view the North Bubble for $\\sim 2-3$ hours a day, and will map its spectrum at 0.1-100 TeV. For the hard primary proton spectrum required to explain five events at IceCube, a high significance detection at HAWC will be achieved in less than 30 days. The combination of results at HAWC and IceCube will substantiate the hadronic model, or constrain its spectral parameters.

  4. 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]

    Quigg, Chris

    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 AFFIDAVIT I (employee), _________________________, certify that my

  5. EFS Exhibit A General Conditions

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration would like submit theCovalentLaboratory |SectorforOXFORD| EnergyAntenna Research Mark5,,1,

  6. EFS Exhibit A General Conditions

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration would like submit theCovalentLaboratory |SectorforOXFORD| EnergyAntenna Research Mark5,,1,2,

  7. EFS Exhibit A General Conditions

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration would like submit theCovalentLaboratory |SectorforOXFORD| EnergyAntenna Research

  8. EFS Exhibit A General Conditions

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration would like submit theCovalentLaboratory |SectorforOXFORD| EnergyAntenna Research4, 3/6/15)

  9. Fermi National Accelerator Laboratory September 2013 A national laboratory funded by the Office of Science of the Department of Energy. www.fnal.gov

    E-Print Network [OSTI]

    Quigg, Chris

    Fermi National Accelerator Laboratory September 2013 A national laboratory funded by the Office energy and materials sci- ence, as well as basic research. Superconducting Radio Frequency Test Facility of Science of the Department of Energy. www.fnal.gov Technologies developed at Fermilab will be used

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

    SciTech Connect (OSTI)

    De Souza, J.C.C.; Pires, M.O.C., E-mail: jose.souza@ufabc.edu.br, E-mail: marcelo.pires@ufabc.edu.br [Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Rua Santa Adélia 166, Santo André, SP, 09210-170 (Brazil)

    2014-03-01

    We show that the galactic dark matter halo, considered composed of an axionlike particles Bose-Einstein condensate [6] trapped by a self-graviting potential [5], 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.

  11. An algorithm for determining EF coils from fixed-boundary equilibria applied to ARIES III

    SciTech Connect (OSTI)

    Bathke, C. (Los Alamos National Lab., NM (United States)); Jardin, S.C.; Kessel, C.E. (Princeton Univ., NJ (United States). Plasma Physics Lab.)

    1991-01-01

    An algorithm that determines the external EF coils required to produce equilibria calculated by high-resolution, fixed-boundary codes is described. The algorithm permits the specification of the poloidal-field-null location. The EF-coil positions on a specified surface located just outside of the TF coils are optimized to minimize the stored magnetic energy. Results of the application of this algorithm to ARIES-3 are also presented. 7 refs., 2 figs., 2 tabs.

  12. A national laboratory funded by the Office of Science of the Department of Energy. www.fnal.gov Fermi National Accelerator Laboratory March 2013

    E-Print Network [OSTI]

    Quigg, Chris

    A national laboratory funded by the Office of Science of the Department of Energy. www.fnal.gov Fermi National Accelerator Laboratory March 2013 Fermilab and the Environment Since its founding in 1967 the designation of a National Environmental Research Park, one of only seven in the United States. These outdoor

  13. Enterprise Fellowship Scheme EFS | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on QA:QA J-E-1 SECTIONRobertsdale, AlabamaETEC GmbH JumpEllenville, NewLtdEnergypediaEntaban Ecoenergeticas SACenter

  14. SOFCo EFS Holdings LLC | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page onRAPID/Geothermal/Exploration/ColoradoRemsenburg-Speonk, NewMichigan:Roxbury,RushS.K EnterpriseTwoSKG SanghaAmerica,SOFCo

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

    SciTech Connect (OSTI)

    Atwood, W. B.; Baldini, L.; Bregeon, J.; Pesce-Rollins, M.; Sgro, C.; Tinivella, M.; Bruel, P.; Cohen-Tanugi, J.; Granot, J.; Longo, F.; Razzaque, S.; Zimmer, S. E-mail: nicola.omodei@stanford.edu

    2013-09-01

    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.

  16. ON THE SPECIFIC HEAT OF FERMI--PASTA--ULAM SYSTEMS

    E-Print Network [OSTI]

    ON THE SPECIFIC HEAT OF FERMI--PASTA--ULAM SYSTEMS Andrea CARATI, Luigi GALGANI Universit`a di)@mat.unimi.it ABSTRACT The specific heat of Fermi Pasta Ulam systems was up to now estimated through the energy, the specific heat is found to vanish for vanishing temperatures. Key Words: Fermi--Pasta--Ulam; specific heat

  17. Fermi Gamma-Ray Space Telescope: High-Energy Results From the...

    Office of Scientific and Technical Information (OSTI)

    Gamma-Ray Space Telescope: High-Energy Results From the First Year Michelson, P.F.; KIPAC, Menlo Park; Atwood, W.B.; Ritz, S.; UC, Santa Cruz UC, Santa Cruz, Phys. Dept....

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

    Energy Savers [EERE]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousMathematicsEnergyInterestedReplacement-2-AA-1Research and FuelingEnergy SecretaryDepartment

  19. Observation of Fermi Polarons in a Tunable Fermi Liquid of Ultracold Atoms

    SciTech Connect (OSTI)

    Schirotzek, Andre; Wu, C.-H.; Sommer, Ariel; Zwierlein, Martin W. [Department of Physics, MIT-Harvard Center for Ultracold Atoms, and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

    2009-06-12

    We have observed Fermi polarons, dressed spin-down impurities in a spin-up Fermi sea of ultracold atoms. The polaron manifests itself as a narrow peak in the impurities' rf spectrum that emerges from a broad incoherent background. We determine the polaron energy and the quasiparticle residue for various interaction strengths around a Feshbach resonance. At a critical interaction, we observe the transition from polaronic to molecular binding. Here, the imbalanced Fermi liquid undergoes a phase transition into a Bose liquid, coexisting with a Fermi sea.

  20. New isospin e ffects in central heavy-ion collisions at Fermi energies

    E-Print Network [OSTI]

    F. Gagnon-Moisan; E. Galichet; M. -F. Rivet; B. Borderie; M. Colonna; R. Roy; G. Ademard; M. Boisjoli; E. Bonnet; R. Bougault; A. Chbihi; J. D. Frankland; D. Guinet; P. Lautesse; E. Legou ee; N. Le Neindre; L. Manduci; P. Marini; P. Napolitani; M. Pârlog; P. Pawlowski; E. Rosato; M. Vigilante

    2012-09-28

    Isospin e ffects on multifragmentation properties were studied thanks to nuclear collisions between di fferent isotopes of xenon beams and tin targets. It is shown that, in central collisions leading to multifragmentation, the mean number of fragments and their mean kinetic energy increase with the neutron-richness of the total system. Comparisons with a stochastic transport model allow to attribute the multiplicity increase to the multifragmentation stage, before secondary decay. The total charge bound in fragments is proposed as an alternate variable to quantify preequilibrium emission and to investigate symmetry energy e ffects.

  1. Isospin Equilibration in Fermi-energy Heavy-ion Nuclear Collisions 

    E-Print Network [OSTI]

    May Jr., Larry

    2015-08-11

    The nuclear Equation of State and the density dependence of the asymmetry energy have been explored via heavy-ion collisions of 35 MeV/nucleon 70Zn,64Ni+64Zn and 64Zn+70Zn,64Ni. The experimental data were collected on the NIMROD-ISiS (Neutron...

  2. Tracing the Evolution of Temperature in Near Fermi Energy Heavy Ion Collisions

    E-Print Network [OSTI]

    J. Wang; R. Wada; T. Keutgen; K. Hagel; Y. G. Ma; M. Murray; L. Qin; A. Botvina; S. Kowalski; T. Materna; J. B. Natowitz; R. Alfarro; J. Cibor; M. Cinausero; Y. El Masri; D. Fabris; E. Fioretto; A. Keksis; M. Lunardon; A. Makeev; N. Marie; E. Martin; Z. Majka; A. Martinez-Davalos; A. Menchaca-Rocha; G. Nebbia; G. Prete; V. Rizzi; A. Ruangma; D. V. Shetty; G. Souliotis; P. Staszel; M. Veselsky; G. Viesti; E. M. Winchester; S. J. Yennello; W. Zipper; A. Ono

    2005-01-19

    The kinetic energy variation of emitted light clusters has been employed as a clock to explore the time evolution of the temperature for thermalizing composite systems produced in the reactions of 26A, 35A and 47A MeV $^{64}$Zn with $^{58}$Ni, $^{92}$Mo and $^{197}$Au. For each system investigated, the double isotope ratio temperature curve exhibits a high maximum apparent temperature, in the range of 10-25 MeV, at high ejectile velocity. These maximum values increase with increasing projectile energy and decrease with increasing target mass. The time at which the maximum in the temperature curve is reached ranges from 80 to 130 fm/c after contact. For each different target, the subsequent cooling curves for all three projectile energies are quite similar. Temperatures comparable to those of limiting temperature systematics are reached 30 to 40 fm/c after the times corresponding to the maxima, at a time when AMD-V transport model calculations predict entry into the final evaporative or fragmentation stage of de-excitation of the hot composite systems. Evidence for the establishment of thermal and chemical equilibrium is discussed.

  3. A Ghoshal-like Test of Equilibration in Near-Fermi-Energy Heavy Ion Collisions

    E-Print Network [OSTI]

    J. Wang; T. Keutgen; R. Wada; K. Hagel; Y. G. Ma; M. Murray; L. Qin; P. Smith; J. B. Natowitz; R. Alfaro; J. Cibor; A. Botvina; M. Cinausero; Y. El Masri; D. Fabris; A. Keksis; S. Kowalski; M. Lunardon; A. Makeev; N. Marie; E. Martin; Z. Majka; A. Martinez-Davalos; A. Menchaca-Rocha; G. Nebbia; S. Moretto; G. Prete; V. Rizzi; A. Ruangma; D. V. Shetty; G. Souliotis; P. Staszel; M. Veselsky; G. Viesti; E. M. Winchester; S. J. Yennello; W. Zipper; A. Ono

    2004-12-22

    Calorimetric and coalescence techniques have been employed to probe equilibration for hot nuclei produced in heavy ion collisions of 35 to 55 MeV/u projectiles with medium mass targets. Entrance channel mass asymmetries and energies were selected in order that very hot composite nuclei of similar mass and excitation would remain after early stage pre-equilibrium particle emission. Inter-comparison of the properties and de-excitation patterns for these different systems provides evidence for the production of hot nuclei with decay patterns relatively independent of the specific entrance channel.

  4. Thermal hard-photons probing multifragmentation in nuclear collisions around the Fermi energy

    E-Print Network [OSTI]

    D. G. d'Enterria; G. Martínez

    2000-07-06

    Hard-photon (E$_{\\gamma} >$ 30 MeV) emission issuing from proton-neutron bremsstrahlung collisions is investigated in four different heavy-ion reactions at intermediate bombarding energies ($^{36}$Ar+$^{197}$Au, $^{107}$Ag, $^{58}$Ni, $^{12}$C at 60{\\it A} MeV) coupling the TAPS photon spectrometer with two charged-particle multidetectors covering more than 80% of the solid angle. The hard-photon spectra of the three heavier targets result from the combination of two distinct exponential distributions with different slope parameters, a result which deviates from the behaviour expected for hard-photon production just in first-chance proton-neutron collisions. The thermal origin of the steeper bremsstrahlung component is confirmed by the characteristics of its slope and angular distribution. Such thermal hard-photons convey undisturbed information of the thermodynamical state of hot and excited nuclear systems undergoing multifragmentation.

  5. Fermi Observations of Gamma-ray Bursts

    SciTech Connect (OSTI)

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

    2010-10-15

    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.

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

    SciTech Connect (OSTI)

    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)

    2012-09-01

    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.

  7. Michigan Nuclear Profile - Fermi

    U.S. Energy Information Administration (EIA) Indexed Site

    Fermi" "Unit","Summer capacity (mw)","Net generation (thousand mwh)","Summer capacity factor (percent)","Type","Commercial operation date","License expiration date"...

  8. Fermi Large Area Telescope observations of high-energy gamma-ray emission from behind-the-limb solar flares

    E-Print Network [OSTI]

    Pesce-Rollins, Melissa; Petrosian, Vahe'; Liu, Wei; da Costa, Fatima Rubio; Allafort, Alice

    2015-01-01

    Fermi-LAT >30 MeV observations have increased the number of detected solar flares by almost a factor of 10 with respect to previous space observations. These sample both the impulsive and long duration phases of GOES M and X class flares. Of particular interest is the recent detections of three solar flares whose position behind the limb was confirmed by the STEREO-B spacecraft. While gamma-ray emission up to tens of MeV resulting from proton interactions has been detected before from occulted solar flares, the significance of these particular events lies in the fact that these are the first detections of >100 MeV gamma-ray emission from footpoint-occulted flares. We will present the Fermi-LAT, RHESSI and STEREO observations of these flares and discuss the various emission scenarios for these sources and implications for the particle acceleration mechanisms.

  9. High-Energy Gamma-Ray Emission From Solar Flares: Summary of Fermi LAT Detections and Analysis of Two M-Class Flares

    E-Print Network [OSTI]

    ,

    2013-01-01

    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...

  10. 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)

    Chu, Steven (U.S. Energy Secretary)

    2012-06-28

    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.

  11. Effective Field Theory and Fermi Surfaces

    E-Print Network [OSTI]

    - d Case 2 d Case Outlook Conclusion #12;Phase Transitions and RG Fixed Points 1 2 aa + r 2 2 + u and show where it fails #12;RG With Fermions Bold Assumptions, low energy degrees of freedom are almost #12;Low Energy Limit Here the low energy excitations are right above and below the Fermi surface

  12. 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)

    Moniz, Ernest [U.S. Energy Secretary

    2014-08-22

    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.

  13. Simultaneous Observations of PKS 2155--304 with H.E.S.S., Fermi, RXTE and ATOM: Spectral Energy Distributions and Variability in a Low State

    SciTech Connect (OSTI)

    Aharonian, F.; Akhperjanian, A.G.; Anton, G.; Barres de Almeida, U.; Bazer-Bachi, A.R.; Becherini, Y.; Behera, B.; Bernlohr, K.; Boisson, C.; Bochow, A.; Borrel, V.; Brion, E.; Brucker, J.; Brun, P.; Buhler, R.; Bulik, T.; Busching, I.; Boutelier, T.; Chadwick, P.M.; Charbonnier, A.; Chaves, R.C.G.; /more authors..

    2009-05-07

    We report on the first simultaneous observations that cover the optical, X-ray, and high-energy gamma-ray bands of the BL Lac object PKS 2155-304. The gamma-ray bands were observed for 11 days, between 2008 August 25 and 2008 September 6 (MJD 54704-54715), jointly with the Fermi Gamma-ray Space Telescope and the HESS atmospheric Cherenkov array, providing the first simultaneous MeV-TeV spectral energy distribution (SED) with the new generation of {gamma}-ray telescopes. The ATOM telescope and the RXTE and Swift observatories provided optical and X-ray coverage of the low-energy component over the same time period. The object was close to the lowest archival X-ray and very high energy (VHE; >100 GeV) state, whereas the optical flux was much higher. The light curves show relatively little ({approx}30%) variability overall when compared to past flaring episodes, but we find a clear optical/VHE correlation and evidence for a correlation of the X-rays with the high-energy spectral index. Contrary to previous observations in the flaring state, we do not find any correlation between the X-ray and VHE components. Although synchrotron self-Compton models are often invoked to explain the SEDs of BL Lac objects, the most common versions of these models are at odds with the correlated variability we find in the various bands for PKS 2155-304.

  14. Specific heat and entropy of tachyon Fermi gas

    E-Print Network [OSTI]

    Ernst Trojan

    2011-08-15

    We consider an ideal Fermi gas of tachyons and derive a low temperature expansion of its thermodynamical functions. The tachyonic specific heat is linear dependent on temperature $C_V=\\epsilon_Fk_FT$ and formally coincides with the specific heat of electron gas if the tachyon Fermi energy is defined as $\\epsilon_F=\\sqrt{k_F-m^2}$.

  15. Investigation of the deformed fermi surfaces 

    E-Print Network [OSTI]

    Lu, Jianxu

    2009-05-15

    = 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 . . . . . . . . . . . . . 10 4 A rough picture of fermi surfaces of DFS states . . . . . . . . . . . . 10 5 3D plot... 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...

  16. THE EFFECT OF RECEIVER DIVERSITY COMBINING ON OPTIMUM ENERGY ALLOCATION AND ENERGY EFFICIENCY OF COOPERATIVE WIRELESS TRANSMISSION SYSTEMS

    E-Print Network [OSTI]

    Brown III, Donald R.

    considers the problem of how to ef ciently allocate transmission energy in a cooperative wireless technique affects both the optimum energy allocation and the overall energy ef ciency of the cooperative the most ef cient strategy, cooperative transmission with EGC tends to be more energy ef cient than direct

  17. Investigating the role of eEF1A2 in motor neuron degeneration 

    E-Print Network [OSTI]

    Griffiths, Lowri Ann

    2011-11-25

    Abnormal expression of the eukaryotic translation elongation factor 1A (eEF1A) has been implicated in disease states such as motor neuron degeneration and cancer. Two variants of eEF1A are found in mammals, named eEF1A1 ...

  18. Model relation between the energy-band edge and the Fermi level of the nondegenerate semiconductor TiO2: Application to electrochemistry

    E-Print Network [OSTI]

    Li, Weixue

    , is demonstrated in the comparative studies of anatase and rutile TiO2 that are used in photocatalysis and dye, photocatalysis, and photovoltaics.9,10 For example, the standard relations between EF and EC/EV based on rigid, i.e., anatase and rutile, are widely used in photocatalysis and dye-sensitized solar cell DSSC

  19. U.S. Department of Energy Awards Contract for Management and...

    Office of Environmental Management (EM)

    Fermi National Accelerator Laboratory to the Fermi Research Alliance, LLC U.S. Department of Energy Awards Contract for Management and Operation of Fermi National Accelerator...

  20. Lab safety aerosols / sprays / fog machines 1. http://www.eliminatorlightingdirect.com/EF_400_400_Watt_Mini_Fog_Machine_p/ef-400.htm

    E-Print Network [OSTI]

    Cohen, Robert E.

    Lab safety ­ aerosols / sprays / fog machines 1 1. http://www.eliminatorlightingdirect.com/EF_400_400_Watt_Mini_Fog_Machine_p/ef-400.htm 2. Vitz, E., Lyle, K. S., J. Chem. Educ., 2008, 85(10), 1385 3. http with surface area (Video of a fog machine in operation) #12;Lab safety ­ aerosols / sprays / fog machines 2 1

  1. Fermi arcs vs. fermi pockets in electron-doped perovskite iridates

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

    He, Junfeng; Hafiz, H.; Mion, Thomas R.; Hogan, T.; Dhital, C.; Oak Ridge National Lab.; Chen, X.; Lin, Qisen; Hashimoto, M.; Lu, D. H.; et al

    2015-02-23

    We report on an angle resolved photoemission (ARPES) study of bulk electron-doped perovskite iridate, (Sr1-xLax)?Ir?O?. Fermi surface pockets are observed with a total electron count in keeping with that expected from La substitution. Depending on the energy and polarization of the incident photons, these pockets show up in the form of disconnected “Fermi arcs”, reminiscent of those reported recently in surface electron-doped Sr?IrO?. Our observed spectral variation is consistent with the coexistence of an electronic supermodulation with structural distortion in the system.

  2. Greenhouse Gas Services AES GE EFS | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on QA:QAsource History View New PagesSustainableGlynn County,Solar Jump to: navigation, searchInitiative ScenarioServices

  3. The TeraFERMI terahertz source at the seeded FERMI free-electron-laser facility

    SciTech Connect (OSTI)

    Perucchi, A. [Sincrotrone Trieste S.C.p.A., Area Science Park, I-34012 Basovizza, Trieste (Italy); INSTM UdR Trieste-ST, Area Science Park, I-34012 Basovizza, Trieste (Italy); Di Mitri, S.; Penco, G.; Allaria, E. [Sincrotrone Trieste S.C.p.A., Area Science Park, I-34012 Basovizza, Trieste (Italy); Lupi, S. [CNR-IOM and Dipartimento di Fisica, Universita di Roma 'La Sapienza', P.le Aldo Moro 2, I-00185 Roma (Italy)

    2013-02-15

    We describe the project for the construction of a terahertz (THz) beamline to be called TeraFERMI at the seeded FERMI free electron laser (FEL) facility in Trieste, Italy. We discuss topics as the underlying scientific case, the choice of the source, the expected performance, and THz beam propagation. Through electron beam dynamics simulations we show that the installation of the THz source in the beam dump section provides a new approach for compressing the electron bunch length without affecting FEL operation. Thanks to this further compression of the FEL electron bunch, the TeraFERMI facility is expected to provide THz pulses with energies up to the mJ range during normal FEL operation.

  4. A hybrid model for studying nuclear multifragmentation around Fermi energy domain: Case for central collision of Xe on Sn

    E-Print Network [OSTI]

    S. Mallik; G. Chaudhuri; S. Das Gupta

    2015-03-17

    Experimental data for central collisions of $^{129}$Xe on $^{119}$Sn at beam energies of (a) 32 MeV/nucleon, (b) 39 MeV/nucleon, (c) 45 MeV/nucleon and (d) 50 MeV/nucleon are compared with results calculated using a hybrid model. We use a transport model (BUU) to obtain the excitation energy per nucleon in the center of mass of the multifragmenting system. The canonical thermodynamic model is then used to determine the temperature which would lead to this excitation energy. With this temperature we use the canonical thermodynamic model to calculate various experimental data such as multiplicities of different composites, probability distribution of the largest cluster etc. Agreement with data establishes the validity of the model.

  5. Primary Isotope Yields and Characteristic Properties of the Fragmenting Source in Heavy-ion Reactions near the Fermi Energies

    E-Print Network [OSTI]

    X. Liu; W. Lin; R. Wada; M. Huang; Z. Chen; G. Q. Xiao; S. Zhang; X. Jin; J. Liu; F. Shi; P. Ren; H. Zheng; J. B. Natowitz; A. Bonasera

    2014-06-13

    For central collisions of $^{40}$Ca $+ ^{40}$Ca at 35 MeV/nucleon, the density and temperature of a fragmenting source have been evaluated in a self-consistent manner using the ratio of the symmetry energy coefficient relative to the temperature, $a_{sym}/T$, extracted from the yields of primary isotopes produced in antisymmetrized molecular dynamics (AMD) simulations. The $a_{sym}/T$ values are extracted from all isotope yields using an improved method based on the Modified Fisher Model (MFM). The values of $a_{sym}/T$ obtained, using different interactions with different density dependencies of the symmetry energy term, are correlated with the values of the symmetry energies at the density of fragment formation. Using this correlation, the fragment formation density is found to be $\\rho/\\rho_0 = 0.67 \\pm 0.02$. Using the input symmetry energy value for each interaction temperature values are extracted as a function of isotope mass $A$. The extracted temperature values are compared with those evaluated from the fluctuation thermometer with a radial flow correction.

  6. Fermi-Teller theory of low-velocity ionization losses applied to monopoles

    SciTech Connect (OSTI)

    Ritson, D.M.

    1982-07-01

    The Fermi-Teller theory was originally used to predict the stopping, by ionization losses, of slow charged particles in materials. The theory is based on a calculation of the energy cost to a uniform Fermi sea. However, the Fermi velocity cancels out in the derivation, so the calculated results also apply to a Thomas-Fermi atom, in which each volume element is considered to be a Fermi sea filled to the top of the potential well with atomic electrons. An outline is presented of the modifications required to make the Fermi-Teller theory valid for a slow monopole traversing an insulator using the Thomas-Fermi model of the atom. (GHT)

  7. Impact of Energy Disaggregation on Consumer Behavior

    E-Print Network [OSTI]

    Chakravarty, Prateek; Gupta, Abahy

    2013-01-01

    Is disaggregation the holy grail of energy ef?ciency? Theis called the Holy Grail 1 of energy efficiency. You cannotIs disaggregation the holy grail of energy ef?ciency? The

  8. Supersymmetry Breaking and Fermi Balls

    E-Print Network [OSTI]

    J. R. Morris; D. Bazeia

    1996-07-22

    A simple model is presented where the disappearance of domain walls and the associated production of ``Fermi balls'', which have been proposed as candidates for cold dark matter, are features which arise rather naturally in response to softly broken supersymmetry.

  9. Nodal to nodeless superconducting energy gap structure change concomitant with Fermi surface reconstruction in the heavy-fermion CeCoIn?

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

    Kim, Hyunsoo; Petrovic, C.; Tanatar, M. A.; Flint, R.; Hu, Rongwei; White, B. D.; Lum, I. K.; Maple, M. B.; Prozorov, R.

    2015-01-15

    The London penetration depth ?(T) was measured in single crystals of Ce1–xRxCoIn?, R=La, Nd, and Yb down to Tmin ? 50 mK (Tc/Tmin ~50) using a tunnel-diode resonator. In the cleanest samples ??(T) is best described by the power law, ??(T) ? Tn, with n ~ 1, consistent with line nodes. Substitutions of Ce with La, Nd, and Yb lead to similar monotonic suppressions of Tc, however, the effects on ??(T) differ. While La and Nd dopings lead to increase of the exponent n and saturation at n ~ 2, as expected for a dirty nodal superconductor, Yb doping leadsmore »to n > 3, suggesting a change from nodal to nodeless superconductivity. This superconducting gap structure change happens in the same doping range where changes of the Fermi surface topology were reported, implying that the nodal structure and Fermi surface topology are closely linked.« less

  10. Emergent quantum criticality, Fermi surfaces, and AdS2

    E-Print Network [OSTI]

    Thomas Faulkner; Hong Liu; John McGreevy; David Vegh

    2011-10-30

    Gravity solutions dual to d-dimensional field theories at finite charge density have a near-horizon region which is AdS_2 x R^{d-1}. The scale invariance of the AdS_2 region implies that at low energies the dual field theory exhibits emergent quantum critical behavior controlled by a (0+1)-dimensional CFT. This interpretation sheds light on recently-discovered holographic descriptions of Fermi surfaces, allowing an analytic understanding of their low-energy excitations. For example, the scaling behavior near the Fermi surfaces is determined by conformal dimensions in the emergent IR CFT. In particular, when the operator is marginal in the IR CFT, the corresponding spectral function is precisely of the "Marginal Fermi Liquid" form, postulated to describe the optimally doped cuprates.

  11. Gamma-Ray Burst observations with Fermi

    E-Print Network [OSTI]

    Bissaldi, Elisabetta; Omodei, Nicola; Vianello, Giacomo; von Kienlin, Andreas

    2015-01-01

    After seven years of science operation, the Fermi mission has brought great advances in the study of Gamma-ray Bursts (GRBs). Over 1600 GRBs have been detected by the Gamma-ray Burst Monitor, and more than 100 of these are also detected by the Large Area Telescope above 30 MeV. We will give an overview of these observations, presenting the common properties in the GRB temporal and spectral behavior at high energies. We will also highlight the unique characteristics of some individual bursts. The main physical implications of these results will be discussed, along with open questions regarding GRB modeling in their prompt and temporally-extended emission phases.

  12. Cinema, Fermi Problems, & General Education

    E-Print Network [OSTI]

    Efthimiou, C J

    2006-01-01

    During the past several years the authors have developed a new approach to the teaching of Physical Science, a general education course typically found in the curricula of nearly every college and university. This approach, called `Physics in Films', uses scenes from popular movies to illustrate physical principles and has excited student interest and improved student performance. The analyses of many of the scenes in `Physics in Films' are a direct application of Fermi calculations -- estimates and approximations designed to make solutions of complex and seemingly intractable problems understandable to the student non-specialist. The intent of this paper is to provide instructors with examples they can use to develop skill in recognizing Fermi problems and making Fermi calculations in their own courses.

  13. Fast Fermi Acceleration and Entropy Growth

    E-Print Network [OSTI]

    Tiago Pereira; Dmitry Turaev

    2015-03-13

    Fermi acceleration is the process of energy transfer from massive objects in slow motion to light objects that move fast. The model for such process is a time-dependent Hamiltonian system. As the parameters of the system change with time, the energy is no longer conserved, which makes the acceleration possible. One of the main problems is how to generate a sustained and robust energy growth. We show that the non-ergodicity of any chaotic Hamiltonian system must universally lead to the exponential growth of energy at a slow periodic variation of parameters. We build a model for this process in terms of a Geometric Brownian Motion with a positive drift and relate it to the entropy increase.

  14. Tissue-specific variants of translation elongation factor eEF1A and their role in cancer 

    E-Print Network [OSTI]

    Janikiewicz, Justyna

    2011-07-05

    Eukaryotic translation elongation factor eEF1A exists in two closely related variant forms, eEF1A1 and eEF1A2, that are encoded by separate loci. The former is the second most abundant protein in the cell and is almost ...

  15. Nodal to nodeless superconducting energy gap structure change concomitant with Fermi surface reconstruction in the heavy-fermion CeCoIn?

    SciTech Connect (OSTI)

    Kim, Hyunsoo [Iowa State Univ., Ames, IA (United States); Petrovic, C. [Brookhaven National Lab. (BNL), Upton, NY (United States); Tanatar, M. A. [Iowa State Univ., Ames, IA (United States); Flint, R. [Iowa State Univ., Ames, IA (United States); Hu, Rongwei [Brookhaven National Lab. (BNL), Upton, NY (United States); White, B. D. [Univ. of California, San Diego, La Jolla, CA (United States); Lum, I. K. [Univ. of California, San Diego, La Jolla, CA (United States); Maple, M. B. [Univ. of California, San Diego, La Jolla, CA (United States); Prozorov, R. [Iowa State Univ., Ames, IA (United States)

    2015-01-01

    The London penetration depth ?(T) was measured in single crystals of Ce1?xRxCoIn?, R=La, Nd, and Yb down to Tmin ? 50??mK (Tc/Tmin ~50) using a tunnel-diode resonator. In the cleanest samples ??(T) is best described by the power law, ??(T) ? Tn, with n ~ 1, consistent with line nodes. Substitutions of Ce with La, Nd, and Yb lead to similar monotonic suppressions of Tc, however, the effects on ??(T) differ. While La and Nd dopings lead to increase of the exponent n and saturation at n ~ 2, as expected for a dirty nodal superconductor, Yb doping leads to n > 3, suggesting a change from nodal to nodeless superconductivity. This superconducting gap structure change happens in the same doping range where changes of the Fermi surface topology were reported, implying that the nodal structure and Fermi surface topology are closely linked.

  16. Edward B. Brothers EFS Consultants, 3 Sunset West. Ithaca. New York '4850

    E-Print Network [OSTI]

    Edward B. Brothers EFS Consultants, 3 Sunset West. Ithaca. New York '4850 Eric D. Prince Dennis W for this family are almost nonexis- tent (Prince et al. 1987), yet age and growth data are important for stock

  17. Fermi velocity renormalization and dynamical gap generation in graphene

    E-Print Network [OSTI]

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

    2015-01-12

    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.

  18. The Specific Heat of Normal, Degenerate Quark Matter: Non-Fermi Liquid Corrections

    E-Print Network [OSTI]

    Daniel Boyanovsky; H. J. de Vega

    2001-02-26

    In normal degenerate quark matter, the exchange of dynamically screened transverse gluons introduces infrared divergences in the quark self-energies that lead to the breakdown of the Fermi liquid description. If the core of neutron stars are composed of quark matter with a normal component, cooling by direct quark Urca processes may be modified by non-Fermi liquid corrections. We find that while the quasiparticle density of states is finite and non-zero at the Fermi surface, its frequency derivative diverges and results in non-Fermi liquid corrections to the specific heat of the normal, degenerate component of quark matter. We study these non-perturbative non-Fermi liquid corrections to the specific heat and the temperature dependence of the chemical potential and show that these lead to a reduction of the specific heat.

  19. Energy-efficient incandescent lamp: Final report

    E-Print Network [OSTI]

    Verderber, R.

    2010-01-01

    more energy than the best " Energy Ef- ficient Incandescentbest available conventional glass envelopes the greatest energyenvelope of best optical accuracy. The energy saving could

  20. Fermi Large Area Telescope Third Source Catalog

    E-Print Network [OSTI]

    ,

    2015-01-01

    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...

  1. Energy-Efficient Task Assignment Framework for Wireless Sensor Networks

    E-Print Network [OSTI]

    Heemin Park; Mani B. Srivastava

    2003-01-01

    and M.B. Srivastava, Energy- Aware Wireless Microsensorin wireless communications and spending more energy. EnergyAn Energy Ef?cient Fair Scheduling Policy for Wireless

  2. Energy-Efficient Task Assignment Framework for Wireless Sensor Networks

    E-Print Network [OSTI]

    Heemin Park; Mani B. Srivastava

    2003-01-01

    and M.B. Srivastava, Energy- Aware Wireless MicrosensorAn Energy Ef?cient Fair Scheduling Policy for Wirelessin wireless communications and spending more energy. Energy

  3. Fermi Site Office Jobs

    Office of Science (SC) Website

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power AdministrationRobust,Field-effectWorkingLosThe 26thI D- 6 0 4ContractFacilities High Energy

  4. Enrico Fermi Patents

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration would like submitKansasCommunities EnergyU.S.Engineering Metal(2) Cu (3) OEnolEnolEnrico

  5. Momentum sharing in imbalanced Fermi systems

    SciTech Connect (OSTI)

    Hen, O. [Tel Aviv Univ., Tel Aviv (Israel); Sargsian, M. [Florida International Univ., Miami, FL (United States); Weinstein, L. B. [Old Dominion Univ., Norfolk, VA (United States); Piasetzky, E. [Tel Aviv Univ., Tel Aviv (Israel), et. al.

    2014-10-30

    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.

  6. Momentum sharing in imbalanced Fermi systems

    E-Print Network [OSTI]

    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

    2014-11-29

    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.

  7. Momentum sharing in imbalanced Fermi systems

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

    Hen, O.; Sargsian, M.; Weinstein, L. B.; Piasetzky, E.

    2014-10-16

    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 starsmore »and may also be observable experimentally in two-spin state, ultra-cold atomic gas systems.« less

  8. Momentum sharing in imbalanced Fermi systems

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

    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.

    2014-10-30

    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

  9. Microsoft Word - frm-070210-GO-EF-1_Form

    Energy Savers [EERE]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousMathematicsEnergyInterested Parties - WAPAEnergy6-09.doc Microsoft Word -

  10. THE FERMI GBM GAMMA-RAY BURST CATALOG: THE FIRST TWO YEARS

    SciTech Connect (OSTI)

    Paciesas, William S.; Bhat, P. N.; Briggs, Michael S.; Burgess, J. Michael; Chaplin, Vandiver; Connaughton, Valerie; Goldstein, Adam; Guiriec, Sylvain; Meegan, Charles A.; Van der Horst, Alexander J.; Von Kienlin, Andreas; Diehl, Roland; Foley, Suzanne; Greiner, Jochen; Gruber, David; Bissaldi, Elisabetta; Fishman, Gerald J.; Gibby, Melissa; Giles, Misty; and others

    2012-03-01

    The Fermi Gamma-ray Burst Monitor (GBM) is designed to enhance the scientific return from Fermi in studying gamma-ray bursts (GRBs). In its first two years of operation GBM triggered on 491 GRBs. We summarize the criteria used for triggering and quantify the general characteristics of the triggered GRBs, including their locations, durations, peak flux, and fluence. This catalog is an official product of the Fermi GBM science team, and the data files containing the complete results are available from the High-Energy Astrophysics Science Archive Research Center.

  11. Anisotropic Fermi Surface and Quantum Limit Transport in High...

    Office of Scientific and Technical Information (OSTI)

    Anisotropic Fermi Surface and Quantum Limit Transport in High Mobility Three-Dimensional Dirac Semimetal Cd 3 As 2 Citation Details In-Document Search Title: Anisotropic Fermi...

  12. Selected Peer-Reviewed Publications 1. Hayward, LNM, dBakker, CMJ, Lusic, H, Gerstenfeld, LC, Grinstaff, MW, Morgan, EF.

    E-Print Network [OSTI]

    (6): 1967-1980. (doi: 10.1007/s00198-010-1390-3). 7. Morgan, EF, Salisbury Palomares, KT, Gleason, RE. Salisbury Palomares, KT, Gerstenfeld, LC, Wigner, N, Lenburg, M, Einhorn, TA, Morgan, EF. Transcriptional:10.1007/s10237-009-0148-3) PMCID: PMC2999671 15. Salisbury Palomares, KT, Gleason, RE, Mason, ZD

  13. A national laboratory funded by the Office of Science of the Department of Energy. www.fnal.gov Fermi National Accelerator Laboratory February 2015

    E-Print Network [OSTI]

    Quigg, Chris

    A national laboratory funded by the Office of Science of the Department of Energy. www transform the way we live. Particle physics research pushes the frontiers of knowledge and technology myriad lesser-known impacts. For example, few people have probably heard that low-energy electron beams

  14. Sharper Fermi LAT images: instrument response functions for an improved event selection

    SciTech Connect (OSTI)

    Portillo, Stephen K. N.; Finkbeiner, Douglas P. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS-51, Cambridge, MA 02138 (United States)

    2014-11-20

    The Large Area Telescope (LAT) on the Fermi Gamma-ray Space Telescope has a point-spread function (PSF) with large tails, consisting of events affected by tracker inefficiencies, inactive volumes, and hard scattering; these tails can make source confusion a limiting factor. The parameter CTBCORE, available in the publicly available Extended Fermi LAT data (available at http://fermi.gsfc.nasa.gov/ssc/data/access/), estimates the quality of each event's direction reconstruction; by implementing a cut in this parameter, the tails of the PSF can be suppressed at the cost of losing effective area. We implement cuts on CTBCORE and present updated instrument response functions derived from the Fermi LAT data itself, along with all-sky maps generated with these cuts. Having shown the effectiveness of these cuts, especially at low energies, we encourage their use in analyses where angular resolution is more important than Poisson noise.

  15. The exponent in the orthogonality catastrophe for Fermi gases

    E-Print Network [OSTI]

    Martin Gebert; Heinrich Küttler; Peter Müller; Peter Otte

    2015-06-15

    We quantify the asymptotic vanishing of the ground-state overlap of two non-interacting Fermi gases in $d$-dimensional Euclidean space in the thermodynamic limit. Given two one-particle Schr\\"odinger operators in finite-volume which differ by a compactly supported bounded potential, we prove a power-law upper bound on the ground-state overlap of the corresponding non-interacting $N$-particle systems. We interpret the decay exponent $\\gamma$ in terms of scattering theory and find $\\gamma = \\pi^{-2}{\\lVert\\arcsin{\\lvert T_E/2\\rvert}\\rVert}_{\\mathrm{HS}}^2$, where $T_E$ is the transition matrix at the Fermi energy $E$. This exponent reduces to the one predicted by Anderson [Phys. Rev. 164, 352-359 (1967)] for the exact asymptotics in the special case of a repulsive point-like perturbation.

  16. Momentum-resolved spectroscopy of a Fermi liquid

    E-Print Network [OSTI]

    Elmer V. H. Doggen; Jami J. Kinnunen

    2014-11-26

    We consider a recent momentum-resolved radio-frequency spectroscopy experiment, in which Fermi liquid properties of a strongly interacting atomic Fermi gas were studied. Here we show that by extending the Brueckner-Goldstone model, we can formulate a theory that goes beyond basic mean-field theories and that can be used for studying spectroscopies of dilute atomic gases in the strongly interacting regime. The model hosts well-defined quasiparticles and works across a wide range of temperatures and interaction strengths. The theory provides excellent qualitative agreement with the experiment. Comparing the predictions of the present theory with the mean-field Bardeen-Cooper-Schrieffer theory yields insights into the role of pair correlations, Tan's contact, and the Hartree mean-field energy shift.

  17. Experimental reconstruction of primary hot isotopes and characteristic properties of the fragmenting source in the heavy ion reactions near the Fermi energy

    E-Print Network [OSTI]

    W. Lin; X. Liu; M. R. D. Rodrigues; S. Kowalski; R. Wada; M. Huang; S. Zhang; Z. Chen; J. Wang; G. Q. Xiao; R. Han; Z. Jin; J. Liu; P. Ren; F. Shi; T. Keutgen; K. Hagel; M. Barbui; C. Bottosso; A. Bonasera; J. B. Natowitz; T. Materna; L. Qin; P. K. Sahu; H. Zheng

    2014-09-14

    The characteristic properties of the hot nuclear matter existing at the time of fragment formation in the multifragmentation events produced in the reaction $^{64}$Zn + $^{112}$Sn at 40 MeV/nucleon are studied. A kinematical focusing method is employed to determine the multiplicities of evaporated light particles, associated with isotopically identified detected fragments. From these data the primary isotopic yield distributions are reconstructed using a Monte Carlo method. The reconstructed yield distributions are in good agreement with the primary isotope distributions obtained from AMD transport model simulations. Utilizing the reconstructed yields, power distribution, Landau free energy, characteristic properties of the emitting source are examined. The primary mass distributions exhibit a power law distribution with the critical exponent, $A^{-2.3}$, for $A \\geq 15$ isotopes, but significantly deviates from that for the lighter isotopes. Landau free energy plots show no strong signature of the first order phase transition. Based on the Modified Fisher Model, the ratios of the Coulomb and symmetry energy coefficients relative to the temperature, $a_{c}/T$ and $a_{sym}/T$, are extracted as a function of A. The extracted $a_{sym}/T$ values are compared with results of the AMD simulations using Gogny interactions with different density dependencies of the symmetry energy term. The calculated $a_{sym}/T$ values show a close relation to the symmetry energy at the density at the time of the fragment formation. From this relation the density of the fragmenting source is determined to be $\\rho /\\rho_{0} = (0.63 \\pm 0.03 )$. Using this density, the symmetry energy coefficient and the temperature of fragmenting source are determined in a self-consistent manner as $a_{sym} = (24.7 \\pm 3.4) MeV$ and $T=(4.9 \\pm 0.2)$ MeV.

  18. NYSERDA's Green Jobs-Green New York Program: Extending Energy Efficiency Financing To Underserved Households

    E-Print Network [OSTI]

    Zimring, Mark

    2011-01-01

    A single lender, Energy Finance Solutions (EFS), ison additional debt to finance energy upgrades? In the past,standards? Several energy efficiency finance programs have

  19. PERSPECTIVE | FOCUS Fishing the Fermi sea

    E-Print Network [OSTI]

    Loss, Daniel

    PERSPECTIVE | FOCUS Fishing the Fermi sea Paul C. Canfield is at Ames Laboratory, and Department feed villages and cities. Those skilled in the art of finding the `right place' to fish were deeply

  20. Enrico Fermi: Audio/Video Clips

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

    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...

  1. Unconventional interaction between vortices in a polarized Fermi gas

    SciTech Connect (OSTI)

    Stojanovic, Vladimir M.; Vincent Liu, W. Kim, Yong Baek

    2008-04-15

    Recently, a homogeneous superfluid state with a single gapless Fermi surface was predicted to be the ground state of an ultracold Fermi gas with spin population imbalance in the regime of molecular Bose-Einstein condensation. We study vortices in this novel state using a symmetry-based effective field theory, which captures the low-energy physics of gapless fermions and superfluid phase fluctuations. This theory is applicable to all spin-imbalanced ultracold Fermi gases in the superfluid regime, regardless of whether the original fermion-pairing interaction is weak or strong. We find a remarkable, unconventional form of the interaction between vortices. The presence of gapless fermions gives rise to a spatially oscillating potential, akin to the RKKY indirect-exchange interaction in non-magnetic metals. We compare the parameters of the effective theory to the experimentally measurable quantities and further discuss the conditions for the verification of the predicted new feature. Our study opens up an interesting question as to the nature of the vortex lattice resulting from the competition between the usual repulsive logarithmic (2D Coulomb) and predominantly attractive fermion-induced interactions.

  2. Nonperturbative Effects on the Ferromagnetic Transition in Repulsive Fermi Gases

    E-Print Network [OSTI]

    Lianyi He; Xu-Guang Huang

    2012-04-26

    It is generally believed that a dilute spin-1/2 Fermi gas with repulsive interactions can undergo a ferromagnetic phase transition to a spin-polarized state at a critical gas parameter $(k_{\\rm F}a)_c$. Previous theoretical predictions of the ferromagnetic phase transition have been based on the perturbation theory, which treats the gas parameter as a small number. On the other hand, Belitz, Kirkpatrick, and Vojta (BKV) have argued that the phase transition in clean itinerant ferromagnets is generically of first order at low temperatures, due to the correlation effects that lead to a nonanalytic term in the free energy. The second-order perturbation theory predicts a first-order phase transition at $(k_{\\rm F}a)_c=1.054$, consistent with the BKV argument. However, since the critical gas parameter is expected to be of order O(1), perturbative predictions may be unreliable. In this paper we study the nonperturbative effects on the ferromagnetic phase transition by summing the particle-particle ladder diagrams to all orders in the gas parameter. We consider a universal repulsive Fermi gas where the effective range effects can be neglected, which can be realized in a two-component Fermi gas of $^6$Li atoms by using a nonadiabatic field switch to the upper branch of a Feshbach resonance with a positive s-wave scattering length. Our theory predicts a second-order phase transition, which indicates that ferromagnetic transition in dilute Fermi gases is possibly a counterexample to the BKV argument. The predicted critical gas parameter $(k_{\\rm F}a)_c=0.858$ is in good agreement with the recent quantum Monte Carlo result $(k_{\\rm F}a)_c=0.86$ for a nearly zero-range potential [S. Pilati, \\emph{et al}., Phys. Rev. Lett. {\\bf 105}, 030405 (2010)]. We also compare the spin susceptibility with the quantum Monte Carlo result and find good agreement.

  3. Study of nuclear giant resonances using a Fermi-liquid method

    E-Print Network [OSTI]

    Bao-Xi Sun

    2012-01-27

    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.

  4. Generalized charge-screening in relativistic Thomas–Fermi model

    SciTech Connect (OSTI)

    Akbari-Moghanjoughi, M.

    2014-10-15

    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.

  5. Enrico Fermi's Impact on Science - John Marburger Speech

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration would like submitKansasCommunities EnergyU.S.Engineering Metal(2) Cu (3) OEnolEnolEnricoFermi

  6. Ingersoll Rand Discovers Hidden Savings with a Three-Tiered Energy...

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

    staff about energy management and new energy-ef- ficient technologies. Operational efficien- cies are also evaluated through Ingersoll Rand's audits that include procurement,...

  7. Fermi Award Winners Saluted | Department of Energy

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of Natural GasAdjustmentsShirley Ann JacksonDepartment ofOffice ofofWindUpcoming events September 3,President Barack Obama

  8. Controlled expansion for certain non-Fermi-liquid metals

    E-Print Network [OSTI]

    Mross, David Fabian

    The destruction of Fermi-liquid behavior when a gapless Fermi surface is coupled to a fluctuating gapless boson field is studied theoretically. This problem arises in a number of different contexts in quantum many-body ...

  9. FERMI@Elettra FEL Design Technical Optimization Final Report

    E-Print Network [OSTI]

    Fawley, William; Penn, Gregory; Allaria, Enrico; De Ninno, Giovanni; Graves, William

    2006-01-01

    LBNL-61333 FERMI@Elettra FEL Design Technical Optimization1 Basic FEL Output5 Important Phenomena which affect the FEL

  10. Milagro Observations of TeV Emission from Galactic Sources in the Fermi Bright Source List

    E-Print Network [OSTI]

    Abdo, A A; Aune, T; Berley, D; Chen, C; Christopher, G E; DeYoung, T; Dingus, B L; Ellsworth, R W; González, M M; Goodman, J A; Hays, E; Hoffman, C M; Huentemeyer, P H; Kolterman, B E; Linnemann, J T; McEnery, J E; Morgan, T; Mincer, A I; Némethy, P; Pretz, J; Ryan, J M; Parkinson, P M Saz; Shoup, A; Sinnis, G; Smith, A J; Vasileiou, V; Walker, G P; Williams, D A; Yodh, G B

    2009-01-01

    We present the result of a search of Milagro sky map for spatial correlations with sources from a subset of the recent Fermi Bright Source List (BSL). The BSL consists of the 205 most significant sources detected above 100 MeV by the Fermi Large Area Telescope. We select sources based on their categorization in the BSL, taking all confirmed or possible Galactic sources in the field of view of Milagro. Of the 34 Fermi sources selected, 14 are observed by Milagro at a significance of 3 standard deviations or more. We conduct this search with a new analysis which employs newly-optimized gamma-hadron separation and utilizes the full 8-year Milagro dataset. Milagro is sensitive to gamma rays above 1 TeV and these results extend the observation of these sources far above the Fermi energy band. With the new analysis and additional data, TeV emission is definitively observed associated with the Fermi pulsar J2229.0+6114, in the the Boomerang Pulsar Wind Nebula (PWN). Furthermore, an extended region of TeV emission is...

  11. Indirect searches for dark matter with the Fermi large area telescopestar

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

    Albert, Andrea

    2015-01-01

    There is overwhelming evidence that non-baryonic dark matter constitutes ~ 27% of the energy density of the Universe. Weakly Interacting Massive Particles (WIMPs) are promising dark matter candidates that may produce ? rays via annihilation or decay detectable by the Fermi Large Area Telescope (LAT). A detection of WIMPs would also indicate the existence of physics beyond the Standard Model. We present recent results from the two cleanest indirect WIMP searches by the Fermi-LAT Collaboration: searches for ?-ray spectral lines and ?-ray emission associated with Milky Way dwarf spheroidal satellite galaxies.

  12. Indirect Searches for Dark Matter with the Fermi Large Area Telescope1

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

    Albert, Andrea

    2015-01-01

    There is overwhelming evidence that non-baryonic dark matter constitutes ~ 27% of the energy density of the Universe. Weakly Interacting Massive Particles (WIMPs) are promising dark matter candidates that may produce ? rays via annihilation or decay detectable by the Fermi Large Area Telescope (LAT). A detection of WIMPs would also indicate the existence of physics beyond the Standard Model. We present recent results from the two cleanest indirect WIMP searches by the Fermi-LAT Collaboration: searches for ?-ray spectral lines and ?-ray emission associated with Milky Way dwarf spheroidal satellite galaxies.

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

    E-Print Network [OSTI]

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

    2010-03-23

    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).

  14. Indirect searches for dark matter with the Fermi large area telescope

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

    Albert, Andrea

    2015-03-24

    There is overwhelming evidence that non-baryonic dark matter constitutes ~ 27% of the energy density of the Universe. Weakly Interacting Massive Particles (WIMPs) are promising dark matter candidates that may produce ? rays via annihilation or decay detectable by the Fermi Large Area Telescope (LAT). A detection of WIMPs would also indicate the existence of physics beyond the Standard Model. We present recent results from the two cleanest indirect WIMP searches by the Fermi-LAT Collaboration: searches for ?-ray spectral lines and ?-ray emission associated with Milky Way dwarf spheroidal satellite galaxies.

  15. Ohmic and step noise from a single trapping center hybridized with a Fermi sea

    E-Print Network [OSTI]

    Rogerio de Sousa; K. Birgitta Whaley; Frank K. Wilhelm; Jan von Delft

    2005-10-27

    We show that single electron tunneling devices such as the Cooper-pair box or double quantum dot can be sensitive to the zero-point fluctuation of a single trapping center hybridized with a Fermi sea. If the trap energy level is close to the Fermi sea and has line-width \\gamma > k_B T, its noise spectrum has an Ohmic Johnson-Nyquist form, whereas for \\gamma < k_B T the noise has a Lorentzian form expected from the semiclassical limit. Trap levels above the Fermi level are shown to lead to steps in the noise spectrum that can be used to probe their energetics, allowing the identification of individual trapping centers coupled to the device.

  16. Relativistic equation of state at subnuclear densities in the Thomas-Fermi approximation

    SciTech Connect (OSTI)

    Zhang, Z. W.; Shen, H., E-mail: shennankai@gmail.com [School of Physics, Nankai University, Tianjin 300071 (China)

    2014-06-20

    We study the non-uniform nuclear matter using the self-consistent Thomas-Fermi approximation with a relativistic mean-field model. The non-uniform matter is assumed to be composed of a lattice of heavy nuclei surrounded by dripped nucleons. At each temperature T, proton fraction Y{sub p} , and baryon mass density ? {sub B}, we determine the thermodynamically favored state by minimizing the free energy with respect to the radius of the Wigner-Seitz cell, while the nucleon distribution in the cell can be determined self-consistently in the Thomas-Fermi approximation. A detailed comparison is made between the present results and previous calculations in the Thomas-Fermi approximation with a parameterized nucleon distribution that has been adopted in the widely used Shen equation of state.

  17. Numerical study of the unitary Fermi gas across the superfluid transition

    E-Print Network [OSTI]

    Goulko, Olga

    2015-01-01

    We present results from Monte Carlo calculations investigating the properties of the homogeneous, spin-balanced unitary Fermi gas in three dimensions. The temperature is varied across the superfluid transition allowing us to determine the temperature dependence of the chemical potential, the energy per particle and the contact density. Numerical artifacts due to finite volume and discretization are systematically studied and removed.

  18. Radiofrequency spectroscopy of a strongly interacting two-dimensional Fermi gas

    E-Print Network [OSTI]

    Bernd Fröhlich; Michael Feld; Enrico Vogt; Marco Koschorreck; Wilhelm Zwerger; Michael Köhl

    2011-02-05

    We realize and study a strongly interacting two-component atomic Fermi gas confined to two dimensions in an optical lattice. Using radio-frequency spectroscopy we measure the interaction energy of the strongly interacting gas. We observe the confinement-induced Feshbach resonance and find the existence of confinement-induced molecules in very good agreement with theoretical predictions.

  19. Corrections to Thomas-Fermi densities at turning points and beyond

    E-Print Network [OSTI]

    Raphael F. Ribeiro; Donghyung Lee; Attila Cangi; Peter Elliott; Kieron Burke

    2015-02-25

    Uniform semiclassical approximations for the number and kinetic-energy densities are derived for many non-interacting fermions in one-dimensional potentials with two turning points. The resulting simple, closed-form expressions contain the leading corrections to Thomas-Fermi theory, involve neither sums nor derivatives, are spatially uniform approximations, and are exceedingly accurate.

  20. A generic method to constrain the dark matter model parameters from Fermi observations of dwarf spheroids

    SciTech Connect (OSTI)

    Tsai, Yue-Lin Sming [National Center for Nuclear Research, Hoza 69, 00-681 Warsaw (Poland); Yuan, Qiang [Key Laboratory of Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, P.R.China (China); Huang, Xiaoyuan, E-mail: Sming.Tsai@fuw.edu.pl, E-mail: yuanq@ihep.ac.cn, E-mail: x_huang@bao.ac.cn [National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012, P.R.China (China)

    2013-03-01

    Observation of ?-rays from dwarf galaxies is an effective way to search for particle dark matter. Using 4-year data of Fermi-LAT observations on a series of Milky Way satellites, we develop a general way to search for the signals from dark matter annihilation in such objects. Instead of giving prior information about the energy spectrum of dark matter annihilation, we bin the Fermi-LAT data into several energy bins and build a likelihood map in the ''energy bin - flux'' plane. The final likelihood of any spectrum can be easily derived through combining the likelihood of all the energy bins. It gives consistent result with that directly calculated using the Fermi Scientific Tool. This method is very efficient for the study of any specific dark matter models with ?-rays. We use the new likelihood map with Fermi-LAT 4 year data to fit the parameter space in three representative dark matter models: i) toy dark matter model, ii) effective dark matter operators, and iii) supersymmetric neutralino dark matter.

  1. FERMI LARGE AREA TELESCOPE OBSERVATIONS OF GRB 110625A

    SciTech Connect (OSTI)

    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)

    2012-08-01

    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.

  2. FERMI NATIONAL ACCELERATOR LABORATORY TUITION ASSISTANCE REQUEST

    E-Print Network [OSTI]

    Quigg, Chris

    FERMI NATIONAL ACCELERATOR LABORATORY TUITION ASSISTANCE REQUEST SECTION 1: EMPLOYEE Employee's Name (as it appears in the Fermilab online directory) ID# Job Title Division/Section/Group Mail Station. __________________________________________________________ ____________________________ Employee's Signature Date SECTION 2: GROUP LEADER AUTHORIZATION Check one: This coursework maintains

  3. Pairing, pseudogap and Fermi arcs in cuprates

    SciTech Connect (OSTI)

    Kaminski, Adam; Gu, Genda; Kondo, Takeshi; Takeuchi, Tsunehiro

    2014-04-29

    We use Angle Resolved Photoemission Spectroscopy (ARPES) to study the relationship between the pseudogap, pairing and Fermi arcs in cuprates. High quality data measured over a wide range of dopings reveals a consistent picture of Fermiology and pairing in these materials. The pseudogap is due to an ordered state that competes with superconductivity rather than preformed pairs. Pairing does occur below Tpair ~ 150K and significantly above Tc, but well below T* and the doping dependence of this temperature scale is distinct from that of the pseudogap. The d-wave gap is present below Tpair, and its interplay with strong scattering creates “artificial” Fermi arcs for Tc < T < Tpair. However, above Tpair, the pseudogap exists only at the antipodal region. This leads to presence of real, gapless Fermi arcs close to the node. The length of these arcs remains constant up to T*, where the full Fermi surface is recovered. We demonstrate that these findings resolve a number of seemingly contradictory scenarios.

  4. Pairing, pseudogap and Fermi arcs in cuprates

    SciTech Connect (OSTI)

    Kaminski, Adam [Iowa State Univ., Ames, IA (United States); Gu, Genda [Brookhaven National Lab. (BNL), Upton, NY (United States); Kondo, Takeshi [The Univ. of Tokyo, Chiba (Japan); Takeuchi, Tsunehiro [Nagoya Univ., Nagoya (Japan)

    2014-10-31

    We use Angle Resolved Photoemission Spectroscopy (ARPES) to study the relationship between the pseudogap, pairing and Fermi arcs in cuprates. High quality data measured over a wide range of dopings reveals a consistent picture of Fermiology and pairing in these materials. The pseudogap is due to an ordered state that competes with superconductivity rather than preformed pairs. Pairing does occur below Tpair ~ 150K and significantly above Tc, but well below T* and the doping dependence of this temperature scale is distinct from that of the pseudogap. The d-wave gap is present below Tpair, and its interplay with strong scattering creates “artificial” Fermi arcs for Tc < T < Tpair. However, above Tpair, the pseudogap exists only at the antipodal region. This leads to presence of real, gapless Fermi arcs close to the node. The length of these arcs remains constant up to T*, where the full Fermi surface is recovered. We demonstrate that these findings resolve a number of seemingly contradictory scenarios.

  5. The Front End Fermi National Accelerator Lab

    E-Print Network [OSTI]

    McDonald, Kirk

    The Front End MAP Review Fermi National Accelerator Lab August 24-26, 2010 Harold G. Kirk Brookhaven National Laboratory #12;August 2426, 2010 MAP ReviewFront End Harold G. Kirk ReviewFront End Harold G. Kirk 3 The Muon Collider/Neutrino Factory

  6. Pairing, pseudogap and Fermi arcs in cuprates

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

    Kaminski, Adam; Kondo, Takeshi; Takeuchi, Tsunehiro; Gu, Genda

    2014-04-29

    We use Angle Resolved Photoemission Spectroscopy (ARPES) to study the relationship between the pseudogap, pairing and Fermi arcs in cuprates. High quality data measured over a wide range of dopings reveals a consistent picture of Fermiology and pairing in these materials. The pseudogap is due to an ordered state that competes with superconductivity rather than preformed pairs. Pairing does occur below Tpair ~ 150K and significantly above Tc, but well below T* and the doping dependence of this temperature scale is distinct from that of the pseudogap. The d-wave gap is present below Tpair, and its interplay with strong scatteringmore »creates “artificial” Fermi arcs for Tc ? T ? Tpair. However, above Tpair, the pseudogap exists only at the antipodal region. This leads to presence of real, gapless Fermi arcs close to the node. The length of these arcs remains constant up to T*, where the full Fermi surface is recovered. As a result, we demonstrate that these findings resolve a number of seemingly contradictory scenarios.« less

  7. 2956r 2010 American Chemical Society pubs.acs.org/EF Energy Fuels 2010, 24, 29562963 : DOI:10.1021/ef9014263

    E-Print Network [OSTI]

    Firoozabadi, Abbas

    Precipitation in Live Oils Zhidong Li and Abbas Firoozabadi* Reservoir Engineering Research Institute (RERI are characterized by considering the pure components, the pseudo-hydrocarbon components, and the hydrocarbon residue. The hydro- carbon residue is further divided into the "heavy" component and asphaltenes. The asphaltene

  8. 4912r 2010 American Chemical Society pubs.acs.org/EF Energy Fuels 2010, 24, 49124918 : DOI:10.1021/ef1007962

    E-Print Network [OSTI]

    Gülder, Ömer L.

    of Binary Mixtures of Ethylene and Butane Isomers and Synergistic Effects Ahmet E. Karatas-,* Mario Commodo fractions of binary mixtures of butane isomers, ethylene-butane isomers, and propane- butane isomers were. Binary mixtures of iso-butane and n-butane did not show any synergistic effects on soot formation

  9. 632r 2011 American Chemical Society pubs.acs.org/EF Energy Fuels 2011, 25, 632639 : DOI:10.1021/ef101238d

    E-Print Network [OSTI]

    Lee, Tonghun

    in using biodiesel in place of or in blends with petrodiesel in diesel engines; however, biodiesel, making them computationally expensive. The present study describes a method for predicting the ignition as a surrogate for biodiesel. The autoignition is predicted using a multistep (8-step) model in order to reduce

  10. 4937r 2010 American Chemical Society pubs.acs.org/EF Energy Fuels 2010, 24, 49374943 : DOI:10.1021/ef100622p

    E-Print Network [OSTI]

    Firoozabadi, Abbas

    temperature of about 4 °C. The kinetic inhibitors are not effective at such a high subcooling. An effective. It is also a clean-burning fuel, which results in low production of CO2. As a result, natural gas inhibitors to change bulk phase properties. Thermodynamic inhibitors, such as methanol, are very effective

  11. Maximal Cherenkov ?-radiation on Fermi-surface of compact stars

    SciTech Connect (OSTI)

    Akbari-Moghanjoughi, M.

    2014-05-15

    The quantum magnetohydrodynamic model is employed in this paper to study the extraordinary (XO) elliptically polarized electromagnetic wave dispersion in quantum plasmas with spin-1/2 magnetization and relativistic degeneracy effects, considering also the electron-exchange and quantum diffraction of electrons. From the lower and upper calculated XO-modes, it is observed that, for electrons on the surface of the Fermi-sphere, the lower XO-mode can excite the Cherenkov radiation by crossing the Fermi-line, with some proper conditions depending on the values of independent plasma parameters, such as the relativistic-degeneracy, the atomic-number of constituent ions, and the magnetic field strength. Particularly, a lower electron number-density and Cherenkov radiation frequency limits are found to exist, for instance, for given values of the plasma ions atomic-number and the magnetic field strength below which the radiation can not be excited by the electrons on the Fermi-surface. This lower density limit increases by decrease in the atomic-number but decreases with decrease in the strength of the ambient magnetic field. It is remarkable that in this research it is discovered that the maximal Cherenkov-radiation per unit-length (the energy radiated by superluminal electrons traveling through the dielectric medium) coincides with the plasma number-densities, which is present in compact stars with the maximal radiation frequency lying in the gamma-ray spectrum. Current study can provide an important plasma diagnostic tool for a wide plasma density range, be it the solid density, the warm dense matter, the inertial confined or the astrophysical compact plasmas and may reveal an important cooling mechanism for white dwarfs. Current findings may also answer the fundamental astrophysical question on the mysterious origin of intense cosmic gamma-ray emissions.

  12. Chrysler: Save Energy Now Assessment Enables a Vehicle Assembly...

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

    helped identify new areas where energy savings could be captured. * By optimizing boiler operation, improving boiler ef- ficiency, and repairing failed steam traps, Chrysler...

  13. Instabilities in a simplified Fermi-like model with Krook-type collisions, intrinsic damping, and a source

    SciTech Connect (OSTI)

    Zale?ny, J. [West Pomeranian University of Technology, Institute of Physics, 70-310 Szczecin (Poland)] [West Pomeranian University of Technology, Institute of Physics, 70-310 Szczecin (Poland)

    2013-08-15

    Plasma micro-instabilities have been investigated numerically using a simplified Fermi-like model extended to include also a Krook-type collision operator containing a source plus collisions and a phenomenologically introduced intrinsic damping. In this simplified Fermi-like model, the wave is modeled as a single potential well. The resonant wave-particle interaction occurs due to bounces of the particles trapped between the well barriers, the height of which depends on the energy exchange between the particles and the wave. A fast numerical algorithm is used for solving the simplified Fermi-like model with the source and the relaxation processes and is briefly described and the obtained numerical results are presented and discussed. The main observation is that the presence of the source and the Krook-type collisions tends to suppress the process of filamentation in phase space and to restore the initial distribution function with free energy. In the Fermi like model including source and collisions, the steady state of the wave amplitude is achieved only due to the presence of the damping in the system. This is different from the collisionless case, when the steady state is achieved due to phase mixing. Some remarks in the end of the paper compare the results of the Fermi-like model with those of the analytical Berk-Breizman model, which inspired the extension of the Fermi-like model to include a source, collisions, and damping.

  14. Detroit Edison's Fermi 1 - Preparation for Reactor Removal

    SciTech Connect (OSTI)

    Swindle, Danny [Sargent and Lundy Engineers, LLC, 55 E. Monroe Street, Chicago, IL 60603 (United States)

    2008-01-15

    This paper is intended to provide information about the ongoing decommissioning tasks at Detroit Edison's Fermi 1 plant, and in particular, the work being performed to prepare the reactor for removal and disposal. In 1972 Fermi 1 was shutdown and the fuel returned to the Atomic Energy Commission. By the end of 1975, a retirement plan was prepared, the bulk sodium removed, and the plant placed in a safe store condition. The plant systems were left isolated with the sodium containing systems inert with carbon dioxide in an attempt to form a carbonate layer, thus passivating the underlying reactive sodium. In 1996, Detroit Edison determined to evaluate the condition of the plant and to make recommendations in relation to the Fermi 1 future plans. At the end of 1997 approval was obtained to remove the bulk asbestos and residual alkali-metals (i.e., sodium and sodium potassium (NaK)). In 2000, full nuclear decommissioning of the plant was approved. To date, the bulk asbestos insulation has been removed, and the only NaK remaining is located in six capillary instrument tubes. The remaining sodium is contained within the reactor, two of the three primary loops, and miscellaneous removed pipes and equipment to be processed. The preferred method for removing or reacting sodium at Fermi 1 is by injecting superheated steam into a heated, nitrogen inert system. The byproducts of this reaction are caustic sodium hydroxide, hydrogen gas, and heat. The decision was made to separate the three primary loops from the reactor for better control prior to processing each loop and the reactor separately. The first loop has already been processed. The main focus is now to process the reactor to allow removal and disposal of the Class C waste prior to the anticipated June 2008 closure of the Barnwell radioactive waste disposal facility located in South Carolina. Lessons learnt are summarized and concern: the realistic schedule and adherence to the schedule, time estimates, personnel accountability, back up or fill in work, work packages, condensation control, radiological contamination control, and organization of the waste stream.

  15. SLAC All Access: Fermi Gamma-ray Space Telescope

    ScienceCinema (OSTI)

    Romani, Roger

    2014-06-24

    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.

  16. Progress from DOE EF RC: Solid-State Solar-Thermal Energy Conversion Center

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious RankADVANCED MANUFACTURINGEnergy Bills andOrderNATIONALofDefine Review Purpose50(S3TEC ) | Department of

  17. burgh Series in the Philosophy and History of Science, vol. 8. Berkeley, Los Angeles, London: University ef lcalifornia Press.

    E-Print Network [OSTI]

    Fitelson, Branden

    : University ef lcalifornia Press. Ricoeur, P. 1970. Fmtd and.+lorop$ New Haven: Yale University Press. -. 1974. The Con@ ollntetpretations, Don Ihde, ed. Evanston, 11.: Northwestern Uni- versity Press. I -1981. Hermeneutus akd the Human Sciences, translated by J. B. Thompson. New York: Cambridge University Press

  18. Stochastic Lagrangian dynamics for charged flows in the E-F regions of ionosphere

    SciTech Connect (OSTI)

    Tang Wenbo; Mahalov, Alex [School of Mathematical and Statistical Sciences, Arizona State University, Tempe, Arizona 85287 (United States)

    2013-03-15

    We develop a three-dimensional numerical model for the E-F region ionosphere and study the Lagrangian dynamics for plasma flows in this region. Our interest rests on the charge-neutral interactions and the statistics associated with stochastic Lagrangian motion. In particular, we examine the organizing mixing patterns for plasma flows due to polarized gravity wave excitations in the neutral field, using Lagrangian coherent structures (LCS). LCS objectively depict the flow topology-the extracted attractors indicate generation of ionospheric density gradients, due to accumulation of plasma. Using Lagrangian measures such as the finite-time Lyapunov exponents, we locate the Lagrangian skeletons for mixing in plasma, hence where charged fronts are expected to appear. With polarized neutral wind, we find that the corresponding plasma velocity is also polarized. Moreover, the polarized velocity alone, coupled with stochastic Lagrangian motion, may give rise to polarized density fronts in plasma. Statistics of these trajectories indicate high level of non-Gaussianity. This includes clear signatures of variance, skewness, and kurtosis of displacements taking polarized structures aligned with the gravity waves, and being anisotropic.

  19. The Fermi Bubbles as Starburst Wind Termination Shocks

    E-Print Network [OSTI]

    Lacki, Brian C

    2013-01-01

    The enhanced star formation in the inner 100 pc of the Galaxy launches a superwind, reaching ~1600 km/s for M82-like parameters. The ram pressure of the wind is very low compared to more powerful starburst winds. I show that halo gas stops the wind a few kpc from the Galactic Center. I argue that the termination shock accelerates cosmic rays, and that the resulting Inverse Compton gamma-rays are visible as the Fermi Bubbles. The Bubbles are thus wind bubbles, which the starburst can inflate within 10 Myr. They remain in steady state as long as the starburst lasts. The shock may accelerate PeV electrons and ultra-high energy protons. The Bubbles may be analogs of galactic wind termination shocks in the intergalactic medium. I discuss the advantages and problems of this model.

  20. Environmental Survey preliminary report, Fermi National Accelerator Laboratory, Batavia, Illinois

    SciTech Connect (OSTI)

    Not Available

    1988-10-01

    This report presents the preliminary findings from the first phase of the Environmental Survey of the US Department of Energy (DOE) Fermi National Accelerator Laboratory (Fermilab), conducted September 14 through 25, 1987. The Survey is being conducted by an interdisciplinary team of environmental specialists led and managed by the Office of Environment, Safety and Health's Office of Environmental Audit. Individual participants for the Survey team are being supplied by a private contractor. The objective of the Survey is to identify environmental problems and areas of environmental risk associated with Fermilab. The Survey covers all environmental media and all areas of environmental regulation. It is being performed in accordance with the DOE Environmental Survey Manual. This phase of the Survey involves the review of existing site environmental data, observations of the operations performed at Fermilab, and interviews with site personnel. 110 refs., 26 figs., 41 tabs.

  1. PROBING CURVATURE EFFECTS IN THE FERMI GRB 110920

    SciTech Connect (OSTI)

    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)

    2013-11-20

    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.

  2. Stoner ferromagnetism of a strongly interacting Fermi gas in the quasirepulsive regime

    E-Print Network [OSTI]

    Lianyi He; Xia-Ji Liu; Xu-Guang Huang; Hui Hu

    2014-12-07

    Recent advances in rapidly quenched ultracold atomic Fermi gases near a Feshbach resonance arise a number of interesting problems, in the context of observing the long-sought Stoner ferromagnetic phase transition. The possibility of experimentally obtaining a "quasirepulsive" regime in the upper branch of the energy spectrum due to the rapid quench is currently debated and theoretically, the Stoner transition has mainly been investigated by using perturbation theory or at high polarization, due to the limited theoretical approaches in the strongly repulsive regime. In this Letter, we present a rigorous prescription for the quasirepulsive branch and prove it by resumming the two-particle virial contributions from the scattering continuum to all orders in the fugacity. By further adopting a nonperturbative large-\\textit{$N$} expansion approach, we determine a finite-temperature phase diagram for the Stoner instability of a quasirepulsive Fermi gas near resonance. Our results agree well with the known quantum Monte-Carlo simulations at zero temperature and recover the known virial expansion prediction at high temperature for arbitrary interaction strengths. At resonance, we find that the unitary Fermi gas undergoes the Stoner transition at about one and a half Fermi temperature, around which the pair formation rate becomes vanishingly small. This suggests a feasible way to observe Stoner ferromagnetism.

  3. Fermi variability study of the candidate pulsar binary 2FGL J0523.3–2530

    SciTech Connect (OSTI)

    Xing, Yi; Wang, Zhongxiang [Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Road, Shanghai 200030 (China); Ng, C.-Y. [Department of Physics, The University of Hong Kong, Pokfulam Road (Hong Kong)

    2014-11-01

    The Fermi source 2FGL J0523.3–2530 has recently been identified as a candidate millisecond pulsar binary with an orbital period of 16.5 hr. We have carried out detailed studies of the source's emission properties by analyzing data taken with the Fermi Large Area Telescope in the 0.2-300 GeV energy range. Long-term, yearly variability from the source has been found, with a factor of four flux variations in 1-300 GeV. From spectral analysis, we find an extra spectral component at 2-3 GeV that causes the source brightening. While no orbital modulations have been found from the Fermi data over the whole period of 2008-2014, orbital modulation in the source's >2 GeV emission is detected during the last 1.5 yr of the Fermi observation. Our results support the millisecond pulsar binary nature of 2FGL J0523.3–2530. Multi-wavelength observations of the source are warranted in order to find any correlated flux variations and thus help determine the origin of the long-term variability, which currently is not understood.

  4. The eukaryotic translation elongation factor eEF1A2 induces neoplastic properties and mediates tumorigenic effects of ZNF217 in precursor cells of human ovarian carcinomas

    SciTech Connect (OSTI)

    Sun, Yu; Wong, Nicholas; Guan, Yinghui; Salamanca, Clara M.; Cheng, Jung Chien; Lee, Jonathan M.; Gray, Joe W.; Auersperg, Nelly

    2008-04-25

    Ovarian epithelial carcinomas (OEC) frequently exhibit amplifications at the 20q13 locus which is the site of several oncogenes, including the eukaryotic elongation factor EEF1A2 and the transcription factor ZNF217. We reported previously that overexpressed ZNF217 induces neoplastic characteristics in precursor cells of OEC. Unexpectedly, ZNF217, which is a transcriptional repressor, enhanced expression of eEF1A2. In this study, array comparative genomic hybridization, single nucleotide polymorphism and Affymetrix analysis of ZNF217-overexpressing cell lines confirmed consistently increased expression of eEF1A2 but not of other oncogenes, and revealed early changes in EEF1A2 gene copy numbers and increased expression at crisis during immortalization. We defined the influence of eEF1A2 overexpression on immortalized ovarian surface epithelial cells, and investigated interrelationships between effects of ZNF217 and eEF1A2 on cellular phenotypes. Lentivirally induced eEF1A2 overexpression caused delayed crisis, apoptosis resistance and increases in serum-independence, saturation densities, and anchorage independence. siRNA to eEF1A2 reversed apoptosis resistance and reduced anchorage independence in eEF1A2-overexpressing lines. Remarkably, siRNA to eEF1A2 was equally efficient in inhibiting both anchorage independence and resistance to apoptosis conferred by ZNF217 overexpression. Our data define neoplastic properties that are caused by eEF1A2 in nontumorigenic ovarian cancer precursor cells, and suggest that eEF1A2 plays a role in mediating ZNF217-induced neoplastic progression.

  5. The free states-related Fermi pocket of cuprate superconductors

    E-Print Network [OSTI]

    Tian De Cao

    2010-07-13

    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.

  6. Classification of Fermi Gamma-RAY Bursts

    E-Print Network [OSTI]

    Horvath, I; Hakkila, J; Bagoly, Z; Preece, R D

    2015-01-01

    The Fermi GBM Catalog has been recently published. Previous classification analyses of the BATSE, RHESSI, BeppoSAX, and Swift databases found three types of gamma-ray bursts. Now we analyzed the GBM catalog to classify the GRBs. PCA and Multiclustering analysis revealed three groups. Validation of these groups, in terms of the observed variables, shows that one of the groups coincides with the short GRBs. The other two groups split the long class into a bright and dim part, as defined by the peak flux. Additional analysis is needed to determine whether this splitting is only a mathematical byproduct of the analysis or has some real physical meaning.

  7. Photovoltaic Energy Conversion

    E-Print Network [OSTI]

    Glashausser, Charles

    Photovoltaic Energy Conversion Frank Zimmermann #12;Solar Electricity Generation Consumes no fuel Electrode Valence Band Conduction Band Fermi Level I- /I3 - Redox Potential Dye 1D 3D* 1D* Energy Levels Counter Electrode Valence Band Conduction Band Fermi Level I- /I3 - Redox Potential Dye 1D 3D* 1D* Energy

  8. ABJM theory as a Fermi gas

    E-Print Network [OSTI]

    Marcos Marino; Pavel Putrov

    2012-03-14

    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.

  9. Design and Commissioning Plan for a Laser Heater for FERMI@elettra

    SciTech Connect (OSTI)

    Zholents, Alexander A.; Qiang, J.; Venturini, M.; Wells,, R.; Wilcox, R.; Di Mitri, S.; Spampinati, S.; Penco, G.

    2008-10-25

    The purpose of a laser heater is to increase the electron beam uncorrelated energy spread as a way to control and ideally suppress the microbunching instability in the linac drive for x-rays FELs. We review the motivations for equipping FERMI with a laser heater and provide a specification for the basics parameters as well as a description of a practical layout including desired diagnostics provisions for both the electron and laser beams. We also outline some useful operational guidelines for commissioning.

  10. Rapid sympathetic cooling to Fermi degeneracy on a chip

    E-Print Network [OSTI]

    Loss, Daniel

    LETTERS Rapid sympathetic cooling to Fermi degeneracy on a chip S. AUBIN*, S. MYRSKOG, M. H. T accelerated evaporative cooling and eliminated the need for multiple vacuum chambers. We demonstrate sympathetic cooling for the first time in a microtrap, and cool 40 K to Fermi degeneracy in just six seconds

  11. Multi-wavelength Emission from the Fermi Bubble III. Stochastic (Fermi) Re-Acceleration of Relativistic Electrons Emitted by SNRs

    E-Print Network [OSTI]

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

    2015-01-01

    We analyse the model of stochastic re-acceleration of electrons, which are emitted by supernova remnants (SNRs) in the Galactic Disk and propagate then into the Galactic halo, in order to explain the origin on nonthermal (radio and gamma-ray) emission from the Fermi Bubbles (FB). We assume that the energy for re-acceleration in the halo is supplied by shocks generated by processes of star accretion onto the central black hole. Numerical simulations show that regions with strong turbulence (places for electron re-acceleration) are located high up in the Galactic Halo about several kpc above the disk. The energy of SNR electrons that reach these regions does not exceed several GeV because of synchrotron and inverse Compton energy losses. At appropriate parameters of re-acceleration these electrons can be re-accelerated up to the energy 10E12 eV which explains in this model the origin of the observed radio and gamma-ray emission from the FB. However although the model gamma-ray spectrum is consistent with the Fe...

  12. Collective modes of p-wave superfluid Fermi gases in BEC phase

    E-Print Network [OSTI]

    Francesco Matera; Matthias F. Wagner

    2015-06-08

    The low-energy modes of a superfluid atomic Fermi gas at zero temperature are investigated. The Bose-Einstein-condensate (BEC) side of the superfluid phase is studied in detail. The atoms are assumed to be in only one internal state, so that for a sufficiently diluted gas the pairing of fermions can be considered effective in the l=1 channel only. In agreement with previous works on p-wave superfluidity in Fermi systems, it is found that the $p_x+ip_y$ phase represents the lowest energy state in both the Bardeen-Cooper-Schrieffer (BCS) and BEC sides. Our calculations show that at low energy three branches of collective modes can emerge, with different species of dispersion relations: a phonon-like mode, a single-particle-like mode and a gapped mode. A comparison with the Bogoliubov excitations of the corresponding spinor Bose condensate is made. They reproduce the dispersion relations of the excitation modes of the p-wave superfluid Fermi gas to a high accuracy.

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

    ScienceCinema (OSTI)

    Isabelle Grenier

    2010-01-08

    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.

  14. Kaluza-Klein Contamination in Fermi Accelerated Environments

    E-Print Network [OSTI]

    Cong-Xin Qiu

    2008-08-09

    Astrophysical constraints of new physics are often limited to weakly interacting light particles, such as axions, the Kaluza-Klein (KK) gravitons from the ADD model, sterile neutrinos and unparticles. We discuss the possibility for an astrophysical scenario to (dis)confirm new physics for heavy particles beyond TeV energy scale. In our scenario, the KK protons (the KK excited quarks/gluons within protons) within the framework of universal extra dimensions (UEDs), are produced by high energy p + p collisions in Fermi accelerated environments, with protonic isotropic spectrum d N / d E \\propto E^-2 up to at least 10^18 eV. Thus, because they are also electrically charged, they should be re-accelerated by mechanism similar to normal protons. The KK states (no matter whether they have already decayed to the lightest KK particle or not) should contaminate 10^-5 to 10^-2 of cosmic-ray events for some fixed energy E (within some suitable assumptions). Hence, if we have techniques to identify them from air shower data, we can constrain UEDs scenario. Our method is an "existence proof" that we can constrain new physics beyond TeV scale or much higher by classical astrophysical scenarios, which can also be generalized to supersymmetric models, the bulk Standard Model fields within the RS model, and the endlessly emerging new models. Moreover, it can exploit domains which have no possibility to be studied in terrestrial experiments.

  15. The Fermi LAT view of the colliding wind binaries

    E-Print Network [OSTI]

    Pshirkov, Maxim S

    2015-01-01

    Colliding wind binaries (CWBs) have been considered as a possible high energy $\\gamma$-ray sources for some time, however no system other than $\\eta$ Car has been detected. In the paper a sample of seven CWBs (WR 11, WR 70, WR 137, WR 140, WR 146, WR 147) which were deemed most favourable candidates by a theoretic modelling was analyzed and almost 7 years of the Fermi-LAT data was used. WR 11 ($\\gamma^2$ Vel) was detected at 6.1$\\sigma$ significance level with a photon flux in 0.1-100 GeV range $(1.8\\pm0.6)\\times10^{-9}~\\mathrm{ph~cm^{-2}~s^{-1}}$, the energy flux $(2.7\\pm0.5)\\times10^{-12}~~\\mathrm{erg~cm^{-2}~s^{-1}}$. At the adopted distance $d=340$ pc that corresponds to luminosity $L=(3.7\\pm0.7)\\times10^{31}~\\mathrm{erg~s^{-1}}$. This luminosity amounts to $\\sim2\\times10^{-6}$ fraction of total wind kinetic power and $\\sim2\\times10^{-4}$ fraction of power injected into the wind-wind interaction region of this system. Upper limits were set on the high-energy flux from the WR 70 and WR 140 systems.

  16. October 200524 F E A T U R EF E A T U R E

    E-Print Network [OSTI]

    the necessary energy production density (rate of ener- gy produced divided by the area of the land needed world. The Need for Fusion Energy Nuclear fission and fusion have sufficient energy density in Table 1, however, since it is not a com- mercially available energy source. Hydrogen is also not list

  17. Diffusive Shock Acceleration: the Fermi Mechanism

    E-Print Network [OSTI]

    Matthew G. Baring

    1997-11-16

    The mechanism of diffusive Fermi acceleration at collisionless plasma shock waves is widely invoked in astrophysics to explain the appearance of non-thermal particle populations in a variety of environments, including sites of cosmic ray production, and is observed to operate at several sites in the heliosphere. This review outlines the principal results from the theory of diffusive shock acceleration, focusing first on how it produces power-law distributions in test-particle regimes, where the shock dynamics are dominated by the thermal populations that provide the seed particles for the acceleration process. Then the importance of non-linear modifications to the shock hydrodynamics by the accelerated particles is addressed, emphasizing how these subsequently influence non-thermal spectral formation.

  18. Fermi matrix element with isospin breaking

    E-Print Network [OSTI]

    P. A. M. Guichon; A. W. Thomas; K. Saito

    2011-01-12

    Prompted by the level of accuracy now being achieved in tests of the unitarity of the CKM matrix, we consider the possible modification of the Fermi matrix element for the $\\beta$-decay of a neutron, including possible in-medium and isospin violating corrections. While the nuclear modifications lead to very small corrections once the Behrends-Sirlin-Ademollo-Gatto theorem is respected, the effect of the $u-d$ mass difference on the conclusion concerning $V_{ud}$ is no longer insignificant. Indeed, we suggest that the correction to the value of $|V_{ud}|^2 \\, + \\, |V_{us}|^2 \\, + \\, |V_{ub}|^2$ is at the level of $10^{-4}$.

  19. Constraints on decaying dark matter from Fermi observations of nearby galaxies and clusters

    SciTech Connect (OSTI)

    Dugger, Leanna; Profumo, Stefano [Department of Astronomy and Department of Physics, University of California Berkeley, 601 Campbell Hall, Berkeley, CA (United States); Jeltema, Tesla E., E-mail: greentee01@gmail.com, E-mail: tesla@ucolick.org, E-mail: profumo@scipp.ucsc.edu [UCO/Lick Observatories, 1156 High St., Santa Cruz, CA 95064 (United States)

    2010-12-01

    We analyze the impact of Fermi gamma-ray observations (primarily non-detections) of selected nearby galaxies, including dwarf spheroidals, and of clusters of galaxies on decaying dark matter models. We show that the fact that galaxy clusters do not shine in gamma rays puts the most stringent limits available to-date on the lifetime of dark matter particles for a wide range of particle masses and decay final states. In particular, our results put strong constraints on the possibility of ascribing to decaying dark matter both the increasing positron fraction reported by PAMELA and the high-energy feature in the electron-positron spectrum measured by Fermi. Observations of nearby dwarf galaxies and of the Andromeda Galaxy (M31) do not provide as strong limits as those from galaxy clusters, while still improving on previous constraints in some cases.

  20. Phase Separation and an upper bound for $?$ for Fermi fluids in the Phase Separation and an upper bound for $?$ for Fermi fluids in the unitary regime

    E-Print Network [OSTI]

    Thomas D. Cohen

    2005-09-12

    An upper bound is derived for $\\Delta$ for a cold dilute fluid of equal amounts of two species of fermion in the unitary regime $k_f a \\to \\infty$ (where $k_f$ is the Fermi momentum and $a$ the scattering length, and $\\Delta$ is a pairing energy: the difference in energy per particle between adding to the system a macroscopic number (but infinitesimal fraction) of particles of one species compared to adding equal numbers of both. The bound is $\\delta \\leq {5/3} (2 (2 \\xi)^{2/5} - (2 \\xi))$ where $\\xi=\\epsilon/\\epsilon_{\\rm FG}$, $\\delta= 2 \\Delta/\\epsilon_{\\rm FG}$; $\\epsilon$ is the energy per particle and $\\epsilon_{\\rm FG}$ is the energy per particle of a noninteracting Fermi gas. If the bound is saturated, then systems with unequal densities of the two species will separate spatially into a superfluid phase with equal numbers of the two species and a normal phase with the excess. If the bound is not saturated then $\\Delta$ is the usual superfluid gap. If the superfluid gap exceeds the maximum allowed by the inequality phase separation occurs.

  1. Sobre a viagem de Enrico Fermi ao Brasil em 1934

    E-Print Network [OSTI]

    Caruso, Francisco

    2014-01-01

    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.

  2. Radio-frequency spectroscopy of ultracold atomic Fermi gases

    E-Print Network [OSTI]

    Schirotzek, Andre

    2010-01-01

    This thesis presents experiments investigating the phase diagram of ultracold atomic Fermi gases using radio-frequency spectroscopy. The tunability of many experimental parameters including the temperature, the interparticle ...

  3. Non-hydrodynamic transport in trapped unitary Fermi gases

    E-Print Network [OSTI]

    Jasmine Brewer; Paul Romatschke

    2015-08-05

    Many strongly coupled fluids are known to share similar hydrodynamic transport properties. In this work we argue that this similarity could extend beyond hydrodynamics to transient dynamics through the presence of non-hydrodynamic modes. We review non-hydrodynamic modes in kinetic theory and gauge/gravity duality and discuss their signatures in trapped Fermi gases close to unitarity. Reanalyzing previously published experimental data, we find hints of non-hydrodynamic modes in cold Fermi gases in two and three dimensions.

  4. Non-hydrodynamic transport in trapped unitary Fermi gases

    E-Print Network [OSTI]

    Brewer, Jasmine

    2015-01-01

    Many strongly coupled fluids are known to share similar hydrodynamic transport properties. In this work we argue that this similarity could extend beyond hydrodynamics to transient dynamics through the presence of non-hydrodynamic modes. We review non-hydrodynamic modes in kinetic theory and gauge/gravity duality and discuss their signatures in trapped Fermi gases close to unitarity. Reanalyzing previously published experimental data, we find hints of non-hydrodynamic modes in cold Fermi gases in two and three dimensions.

  5. Fermi plug-in for TEMPO2 documentation L. Guillemot

    E-Print Network [OSTI]

    Nishikawa, Ken-Ichi

    Fermi plug-in for TEMPO2 documentation L. Guillemot e-mail: guillemo at mpifr-bonn.mpg.de v4.0, 24/09/2011 #12;Introduction The Fermi plug-in for TEMPO2 allows to calculate a pulsar rotational phase for each by TEMPO2. The plug-in first calculates the position of the observatory for each photon time, using

  6. Spectral zeta function and non-perturbative effects in ABJM Fermi-gas

    E-Print Network [OSTI]

    Yasuyuki Hatsuda

    2015-03-26

    The exact partition function in ABJM theory on three-sphere can be regarded as a canonical partition function of a non-interacting Fermi-gas with an unconventional Hamiltonian. All the information on the partition function is encoded in the discrete spectrum of this Hamiltonian. We explain how (quantum mechanical) non-perturbative corrections in the Fermi-gas system appear from a spectral consideration. Basic tools in our analysis are a Mellin-Barnes type integral representation and a spectral zeta function. From a consistency with known results, we conjecture that the spectral zeta function in the ABJM Fermi-gas has an infinite number of "non-perturbative" poles, which are invisible in the semi-classical expansion of the Planck constant. We observe that these poles indeed appear after summing up perturbative corrections. As a consequence, the perturbative resummation of the spectral zeta function causes non-perturbative corrections to the grand canonical partition function. We also present another example associated with a spectral problem in topological string theory. A conjectured non-perturbative free energy on the resolved conifold is successfully reproduced in this framework.

  7. THE SECOND FERMI GBM GAMMA-RAY BURST CATALOG: THE FIRST FOUR YEARS

    SciTech Connect (OSTI)

    Von Kienlin, Andreas; Greiner, Jochen; Gruber, David [Max-Planck-Institut für extraterrestrische Physik, Giessenbachstrasse 1, D-85748 Garching (Germany); Meegan, Charles A.; Bhat, P. N.; Briggs, Michael S.; Burgess, J. Michael; Chaplin, Vandiver; Connaughton, Valerie; Goldstein, Adam [University of Alabama in Huntsville, 320 Sparkman Drive, Huntsville, AL 35805 (United States); Paciesas, William S.; Cleveland, William [Universities Space Research Association, 320 Sparkman Drive, Huntsville, AL 35805 (United States); Bissaldi, Elisabetta [Istituto Nazionale di Fisica Nucleare, Sezione di Trieste, I-34127 Trieste (Italy); Byrne, David; Fitzpatrick, Gerard; Foley, Suzanne [School of Physics, University College Dublin, Belfield, Stillorgan Road, Dublin 4 (Ireland); Collazzi, Andrew C. [Astrophysics Office, ZP 12, NASA-Marshall Space Flight Center, Huntsville, AL 35812 (United States); Gibby, Melissa; Giles, Misty [Jacobs Technology, Inc., Huntsville, AL 35806 (United States); Guiriec, Sylvain [NASA-Goddard Space Flight Center, Greenbelt, MD 20771 (United States); and others

    2014-03-01

    This is the second of a series of catalogs of gamma-ray bursts (GRBs) observed with the Fermi Gamma-ray Burst Monitor (GBM). It extends the first two-year catalog by two more years, resulting in an overall list of 953 GBM triggered GRBs. The intention of the GBM GRB catalog is to provide information to the community on the most important observables of the GBM detected GRBs. For each GRB the location and main characteristics of the prompt emission, the duration, peak flux and fluence are derived. The latter two quantities are calculated for the 50-300 keV energy band, where the maximum energy release of GRBs in the instrument reference system is observed and also for a broader energy band from 10-1000 keV, exploiting the full energy range of GBMs low-energy detectors. Furthermore, information is given on the settings and modifications of the triggering criteria and exceptional operational conditions during years three and four in the mission. This second catalog is an official product of the Fermi GBM science team, and the data files containing the complete results are available from the High-Energy Astrophysics Science Archive Research Center.

  8. Fermi-liquid damping and NMR relaxation in superconductors

    SciTech Connect (OSTI)

    Tewari, S.; Ruvalds, J.

    1996-03-01

    Electron collisions for a two-dimensional Fermi-liquid (FL) are shown to give a quasiparticle damping with interesting frequency and temperature variations in the BCS superconducting state. The spin susceptibility which determines the structure of the damping is analyzed in the normal state for a Hubbard model with a constant on-site Coulomb repulsion. This is then generalized to the superconducting state by including coherence factors and self-energy and vertex corrections. Calculations of the NMR relaxation rate reveal that the FL damping structure can reduce the Hebel-Slichter peak, in agreement with data on the organic superconductor (MDT-TTF){sub 2}AuI{sub 2} (methylenedithiotetrathiafulvalene salt). However, the strongly suppressed FL damping in the superconducting state does not eliminate the Hebel-Slichter peak, and thus suggests that other mechanisms are needed to explain the NMR data on (TMTSF){sub 2}ClO{sub 4} (bistetramethyltetraselenafulvaleneperchlorate), the BEDT organic compounds, and cuprate superconductors. Predictions of the temperature variation of the damping and the spin response are given over a wide frequency range as a guide to experimental probes of the symmetry of the superconducting pairs. {copyright} {ital 1996 The American Physical Society.}

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

    E-Print Network [OSTI]

    Lu, Jianxu

    2008-10-10

    Variational method is used to investigate, at zero temperature, the deformed- Fermi-surfaces mechanism for solving the problem of superconducting pairing of two species of fermions (i.e., spin-up and -down) of mismatched ...

  10. Where are the Fermi lines coming from?

    SciTech Connect (OSTI)

    Rao, Kanishka; Whiteson, Daniel, E-mail: krao@uci.edu, E-mail: daniel@uci.edu [Dept. of Physics and Astronomy, UC Irvine, Irvine, CA (United States)

    2013-03-01

    We estimate the spatial locations of sources of the the observed features in the Fermi-LAT photon spectrum at E{sub ?} = 110 and E{sub ?} = 130 GeV. We determine whether they are consistent with emission from a single source, as would be expected in their interpretation as ?? and ?Z lines from dark matter annhiliation, as well as whether they are consistent with a dark matter halo positioned at the center of the galaxy. We take advantage of the per-photon measured incident angle in reconstructing the line features. In addition, we use a data-driven background model rather than making the assumption of a feature-less background. We localize the sources of the features at 110 and 130 GeV. Assuming an Einasto (NFW) density model we find the 130 GeV line to be offset from the Galactic center by 285 (280) pc, the 110 GeV line by 60 (30) pc with a large relative separation of 220 (240) pc. However, we find this displacement of each source from the Galactic center, as well as their relative displacement to be statistically consistent with a single Einasto or NFW dark matter halo at the center of the galaxy.

  11. The 2nd Fermi GBM Gamma-Ray Burst Catalog: The First Four Years

    E-Print Network [OSTI]

    von Kienlin, Andreas; Paciesas, William S; Bhat, P N; Bissaldi, Elisabetta; Briggs, Michael S; Burgess, J Michael; Byrne, David; Chaplin, Vandiver; Cleveland, William; Connaughton, Valerie; Collazzi, Andrew C; Fitzpatrick, Gerard; Foley, Suzanne; Gibby, Melissa; Giles, Misty; Goldstein, Adam; Greiner, Jochen; Gruber, David; Guiriec, Sylvain; van der Horst, Alexander J; Kouveliotou, Chryssa; Layden, Emily; McBreen, Sheila; McGlynn, Sinead; Pelassa, Veronique; Preece, Robert D; Rau, Arne; Tierney, Dave; Wilson-Hodge, Colleen A; Xiong, Shaolin; Younes, George; Yu, Hoi-Fung

    2014-01-01

    This is the second of a series of catalogs of gamma-ray bursts (GRBs) observed with the Fermi Gamma-ray Burst Monitor (GBM). It extends the first two-year catalog by two more years, resulting in an overall list of 953 GBM triggered GRBs. The intention of the GBM GRB catalog is to provide information to the community on the most important observables of the GBM detected GRBs. For each GRB the location and main characteristics of the prompt emission, the duration, peak flux and fluence are derived. The latter two quantities are calculated for the 50 - 300 keV energy band, where the maximum energy release of GRBs in the instrument reference system is observed and also for a broader energy band from 10 - 1000 keV, exploiting the full energy range of GBMs low-energy detectors. Furthermore, information is given on the settings and modifications of the triggering criteria and exceptional operational conditions during years three and four in the mission. This second catalog is an official product of the Fermi GBM sci...

  12. Towards Energy and Resource Efficient Manufacturing: A Processes and Systems Approach

    E-Print Network [OSTI]

    2012-01-01

    M (2011) Assessment of Energy and Resource Consumption ofAs pointed out above, the energy and resource consumption ofasp Towards energy and resource ef?cient manufacturing: A

  13. Climate and Transportation Solutions: Findings from the 2009 Asilomar Conference on Transportation and Energy Policy

    E-Print Network [OSTI]

    Sperling, Daniel; Cannon, James S.

    2010-01-01

    Strategy A Vehicle Energy Ef?ciency B Alternative Fuelalternative fuels will solve transportation energy problems motivates policies to promote alternative fuel vehicles (vehicles and alternative fuels, as well as estimating energy

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

    E-Print Network [OSTI]

    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

    2015-01-01

    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...

  15. Extremely correlated Fermi liquids in the limit of infinite dimensions

    SciTech Connect (OSTI)

    Perepelitsky, Edward, E-mail: eperepel@ucsc.edu; Sriram Shastry, B.

    2013-11-15

    We study the infinite spatial dimensionality limit (d??) of the recently developed Extremely Correlated Fermi Liquid (ECFL) theory (Shastry 2011, 2013) [17,18] for the t–J model at J=0. We directly analyze the Schwinger equations of motion for the Gutzwiller projected (i.e. U=?) electron Green’s function G. From simplifications arising in this limit d??, we are able to make several exact statements about the theory. The ECFL Green’s function is shown to have a momentum independent Dyson (Mori) self energy. For practical calculations we introduce a partial projection parameter ?, and obtain the complete set of ECFL integral equations to O(?{sup 2}). In a related publication (Zitko et al. 2013) [23], these equations are compared in detail with the dynamical mean field theory for the large U Hubbard model. Paralleling the well known mapping for the Hubbard model, we find that the infinite dimensional t–J model (with J=0) can be mapped to the infinite-U Anderson impurity model with a self-consistently determined set of parameters. This mapping extends individually to the auxiliary Green’s function g and the caparison factor ?. Additionally, the optical conductivity is shown to be obtainable from G with negligibly small vertex corrections. These results are shown to hold to each order in ?. -- Highlights: •Infinite-dimensional t–J model (J=0) studied within new ECFL theory. •Mapping to the infinite U Anderson model with self consistent hybridization. •Single particle Green’s function determined by two local self energies. •Partial projection through control variable ?. •Expansion carried out to O(?{sup 2}) explicitly.

  16. FINAL–REPORT NO. 2: INDEPENDENT CONFIRMATORY SURVEY SUMMARY AND RESULTS FOR THE ENRICO FERMI ATOMIC POWER PLANT, UNIT 1, NEWPORT, MICHIGAN (DOCKET NO. 50 16; RFTA 10-004)

    SciTech Connect (OSTI)

    Erika Bailey

    2011-07-07

    The Enrico Fermi Atomic Power Plant, Unit 1 (Fermi 1) was a fast breeder reactor design that was cooled by sodium and operated at essentially atmospheric pressure. On May 10, 1963, the Atomic Energy Commission (AEC) granted an operating license, DPR-9, to the Power Reactor Development Company (PRDC), a consortium specifically formed to own and operate a nuclear reactor at the Fermi 1 site. The reactor was designed for a maximum capability of 430 megawatts (MW); however, the maximum reactor power with the first core loading (Core A) was 200 MW. The primary system was filled with sodium in December 1960 and criticality was achieved in August 1963.

  17. Strongly correlated electron behavior : superconductivity and non-Fermi liquid behavior in Ce?-xRxColn?

    E-Print Network [OSTI]

    Gonzales, Eileen

    2009-01-01

    T-? cw ), where N A is avogadro’s number, µ ef f is the e?T-? cw ), where N A is avogadro’s number, µ ef f is the e?

  18. Improved Measurement of the Positive Muon Lifetime and Determination of the Fermi Constant

    E-Print Network [OSTI]

    MuLan Collaboration; D. B. Chitwood; T. I. Banks; M. J. Barnes; S. Battu; R. M. Carey; S. Cheekatmalla; S. M. Clayton; J. Crnkovic; K. M. Crowe; P. T. Debevec; S. Dhamija; W. Earle; A. Gafarov; K. Giovanetti; T. P. Gorringe; F. E. Gray; M. Hance; D. W. Hertzog; M. F. Hare; P. Kammel; B. Kiburg; J. Kunkle; B. Lauss; I. Logashenko; K. R. Lynch; R. McNabb; J. P. Miller; F. Mulhauser; C. J. G. Onderwater; C. S. Ozben; Q. Peng; C. C. Polly; S. Rath; B. L. Roberts; V. Tishchenko; G. D. Wait; J. Wasserman; D. M. Webber; P. Winter; P. A. Zolnierczuk

    2008-02-08

    The mean life of the positive muon has been measured to a precision of 11 ppm using a low-energy, pulsed muon beam stopped in a ferromagnetic target, which was surrounded by a scintillator detector array. The result, tau_mu = 2.197013(24) us, is in excellent agreement with the previous world average. The new world average tau_mu = 2.197019(21) us determines the Fermi constant G_F = 1.166371(6) x 10^-5 GeV^-2 (5 ppm). Additionally, the precision measurement of the positive muon lifetime is needed to determine the nucleon pseudoscalar coupling g_P.

  19. On the Fermi and Gamow-Teller strength distribution in medium-heavy mass nuclei

    E-Print Network [OSTI]

    Rodin, V A

    2003-01-01

    The BCS model is incorporated in the Continuum-Random-Phase-Approximation (CRPA) method to formulate a version of the partially self-consistent pn-quasiparticle CRPA (QCRPA) approach. Within the approach the Fermi and Gamow-Teller strength distributions in single- and double- closed-shell nuclei are calculated for a wide excitation energy interval, including the region of the isovector monopole and spin-monopole giant resonances. The isospin and configurational splittings of the Gamow-Teller resonance are also analyzed. The results obtained for $^{90}$Nb, the Sb isotopes and $^{208}$Bi are compared with available experimental data.

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

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration would like submitKansasCommunities EnergyU.S.Engineering Metal(2) Cu (3) OEnolEnolEnrico Fermi

  1. Analysis of the cumulative neutrino flux from Fermi-LAT blazar populations using 3 years of IceCube data

    E-Print Network [OSTI]

    Glüsenkamp, Thorsten

    2015-01-01

    The recent discovery of a diffuse neutrino flux up to PeV energies raises the question of which populations of astrophysical sources contribute to this diffuse signal. One extragalactic candidate source population to produce high-energy neutrinos are Blazars. We present results from a likelihood analysis searching for cumulative neutrino emission from Blazar populations selected with the 2nd Fermi-LAT AGN catalog (2LAC) using an IceCube data set that has been optimized for the detection of individual sources. In contrast to previous searches with IceCube, the investigated populations contain up to hundreds of sources, the biggest one being the entire Blazar sample measured by the Fermi-LAT. No significant neutrino signal was found from any of these populations. Some implications of this non-observation for the origin of the observed PeV diffuse signal will be discussed.

  2. Emission vs Fermi coordinates: applications to relativistic positioning systems

    E-Print Network [OSTI]

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

    2008-09-05

    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.

  3. Evolution of Holographic Fermi Arcs from a Mott Insulator

    E-Print Network [OSTI]

    Garrett Vanacore; Srinidhi T. Ramamurthy; Philip W. Phillips

    2015-08-10

    We study fermions in an electrically-probed and asymptotically anti-de Sitter Schwarzschild spacetime which interact via a novel chiral symmetry-preserving interaction. Computing the dual fermion two-point correlator, we show that this bulk interaction anisotropically gaps Fermi surfaces of the boundary spectrum. Consequently, the interaction we devise provides a holographic model for Fermi arcs seen ubiquitously in the pseudogap regime of the cuprates. Our interaction is a modification of the chiral symmetry-breaking Pauli coupling, which has previously been proposed as the holographic realization of Mott physics. The onset of Mott insulation and pseudogap physics are respectively discussed in the context of bulk chiral and boundary parity symmetry breaking, and the Mott transition is interpreted as a deconfinement transition of non-Fermi liquid excitations.

  4. Evolution of Holographic Fermi Arcs from a Mott Insulator

    E-Print Network [OSTI]

    Vanacore, Garrett; Phillips, Philip W

    2015-01-01

    We study fermions in an electrically-probed and asymptotically anti-de Sitter Schwarzschild spacetime which interact via a novel chiral symmetry-preserving interaction. Computing the dual fermion two-point correlator, we show that this bulk interaction anisotropically gaps Fermi surfaces of the boundary spectrum. Consequently, the interaction we devise provides a holographic model for Fermi arcs seen ubiquitously in the pseudogap regime of the cuprates. Our interaction is a modification of the chiral symmetry-breaking Pauli coupling, which has previously been proposed as the holographic realization of Mott physics. The onset of Mott insulation and pseudogap physics are respectively discussed in the context of bulk chiral and boundary parity symmetry breaking, and the Mott transition is interpreted as a deconfinement transition of non-Fermi liquid excitations.

  5. Thermal conductivity of the one-dimensional Fermi-Hubbard model

    E-Print Network [OSTI]

    C. Karrasch; D. M. Kennes; F. Heidrich-Meisner

    2015-06-18

    We study the thermal conductivity of the one-dimensional Fermi-Hubbard model at finite temperature using a density matrix renormalization group approach. The integrability of this model gives rise to ballistic thermal transport. We calculate the temperature dependence of the thermal Drude weight at half filling for various interactions and moreover, we compute its filling dependence at infinite temperature. The finite-frequency contributions originating from the fact that the energy current is not a conserved quantity are investigated as well. We report evidence that breaking the integrability through a nearest-neighbor interaction leads to vanishing Drude weights and diffusive energy transport. Moreover, we demonstrate that energy spreads ballistically in local quenches with initially inhomogeneous energy density profiles in the integrable case. We discuss the relevance of our results for thermalization in ultra-cold quantum gas experiments and for transport measurements with quasi-one dimensional materials.

  6. Space Detectors for Gamma Rays (100 MeV - 100 GeV): from EGRET to Fermi LAT

    E-Print Network [OSTI]

    Thompson, David J

    2015-01-01

    The design of spaceborne high-energy (E>100 MeV) gamma-ray detectors depends on two principal factors: (1) the basic physics of detecting and measuring the properties of the gamma rays; and (2) the constraints of operating such a detector in space for an extended period. Improvements in technology have enabled major advances in detector performance, as illustrated by two successful instruments, EGRET on the Compton Gamma Ray Observatory and LAT on the Fermi Gamma-ray Space Telescope.

  7. Role of nucleonic Fermi surface depletion in neutron star cooling

    E-Print Network [OSTI]

    Dong, J M; Zhang, H F; Zuo, W

    2015-01-01

    The Fermi surface depletion of beta-stable nuclear matter is calculated to study its effects on several physical properties which determine the neutron star thermal evolution. The neutron and proton Z factors measuring the corresponding Fermi surface depletions, are calculated within the Brueckner-Hartree-Fock approach employing the AV18 two-body force supplemented by a microscopic three body force. Neutrino emissivity, heat capacity and, in particular, neutron 3PF2 superfluidity turn out to be reduced, especially at high baryonic density, to such an extent that the cooling rates of young neutron stars are significantly slowed

  8. Role of nucleonic Fermi surface depletion in neutron star cooling

    E-Print Network [OSTI]

    J. M. Dong; U. Lombardo; H. F. Zhang; W. Zuo

    2015-12-09

    The Fermi surface depletion of beta-stable nuclear matter is calculated to study its effects on several physical properties which determine the neutron star thermal evolution. The neutron and proton Z factors measuring the corresponding Fermi surface depletions, are calculated within the Brueckner-Hartree-Fock approach employing the AV18 two-body force supplemented by a microscopic three body force. Neutrino emissivity, heat capacity and, in particular, neutron 3PF2 superfluidity turn out to be reduced, especially at high baryonic density, to such an extent that the cooling rates of young neutron stars are significantly slowed

  9. Poisson-Fermi Model of Single Ion Activities

    E-Print Network [OSTI]

    Liu, Jinn-Liang

    2015-01-01

    A Poisson-Fermi model is proposed for calculating activity coefficients of single ions in strong electrolyte solutions based on the experimental Born radii and hydration shells of ions in aqueous solutions. The steric effect of water molecules and interstitial voids in the first and second hydration shells play an important role in our model. The screening and polarization effects of water are also included in the model that can thus describe spatial variations of dielectric permittivity, water density, void volume, and ionic concentration. The activity coefficients obtained by the Poisson-Fermi model with only one adjustable parameter are shown to agree with experimental data, which vary nonmonotonically with salt concentrations.

  10. Technical Design and Optimization Study for the FERMI@Elettra FEL Photoinjector

    E-Print Network [OSTI]

    Lidia, Steven M.; Penco, Giuseppe; Trovo', Mauro

    2006-01-01

    Source for the ELETTRA Linac FEL”, ST/M-03/02, May 2003. [for the FERMI @ Elettra FEL”, Proceedings of the 27 thStudy for the FERMI@Elettra FEL Photoinjector Steve Lidia (

  11. Density dependence of symmetry energy and collective transverse in-plane flow

    E-Print Network [OSTI]

    Sakshi Gautam; Aman D. Sood; Rajeev K. Puri; J. Aichelin

    2011-12-13

    We study the sensitivity of the collective transverse in-plane flow to the symmetry energy and its density dependence at Fermi energies and higher incident energies. We find that collective transverse in-plane flow is sensitive to the symmetry energy and its density dependence at Fermi energies whereas it shows insensitivity at higher incident energies.

  12. Characterization of the Deoxynucleotide Triphosphate Triphosphohydrolase (dNTPase) Activity of the EF1143 Protein from Enterococcus faecalis and Crystal Structure of the Activator-Substrate Complex

    SciTech Connect (OSTI)

    Vorontsov, Ivan I.; Minasov, George; Kiryukhina, Olga; Brunzelle, Joseph S.; Shuvalova, Ludmilla; Anderson, Wayne F. (NWU)

    2012-06-19

    The EF1143 protein from Enterococcus faecalis is a distant homolog of deoxynucleotide triphosphate triphosphohydrolases (dNTPases) from Escherichia coli and Thermus thermophilus. These dNTPases are important components in the regulation of the dNTP pool in bacteria. Biochemical assays of the EF1143 dNTPase activity demonstrated nonspecific hydrolysis of all canonical dNTPs in the presence of Mn{sup 2+}. In contrast, with Mg{sup 2+} hydrolysis required the presence of dGTP as an effector, activating the degradation of dATP and dCTP with dGTP also being consumed in the reaction with dATP. The crystal structure of EF1143 and dynamic light scattering measurements in solution revealed a tetrameric oligomer as the most probable biologically active unit. The tetramer contains four dGTP specific allosteric regulatory sites and four active sites. Examination of the active site with the dATP substrate suggests an in-line nucleophilic attack on the {alpha}-phosphate center as a possible mechanism of the hydrolysis and two highly conserved residues, His-129 and Glu-122, as an acid-base catalytic dyad. Structural differences between EF1143 apo and holo forms revealed mobility of the {alpha}3 helix that can regulate the size of the active site binding pocket and could be stabilized in the open conformation upon formation of the tetramer and dGTP effector binding.

  13. Multi-wavelength emission from the Fermi bubbles. I. Stochastic acceleration from background plasma

    SciTech Connect (OSTI)

    Cheng, K. S.; Chernyshov, D. O.; Dogiel, V. A.; Ko, C. M.

    2014-07-20

    We analyze 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 the leptonic origin of the nonthermal radiation from the bubbles, these electrons should be produced somehow in situ because of the 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 stars 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 on 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 explain the observed fluxes of radio and gamma-ray emission from the bubbles, but the range of permitted parameters of the model is strongly restricted.

  14. Fermi-LAT ?-ray anisotropy and intensity explained by unresolved radio-loud active galactic nuclei

    SciTech Connect (OSTI)

    Mauro, Mattia Di; Cuoco, Alessandro; Donato, Fiorenza [Dipartimento di Fisica, Università di Torino, via P. Giuria 1, Torino, 10125 Italy (Italy); Siegal-Gaskins, Jennifer M., E-mail: mattia.dimauro@to.infn.it, E-mail: alessandro.cuoco@to.infn.it, E-mail: donato@to.infn.it, E-mail: jsg@tapir.caltech.edu [California Institute of Technology, 1200 E. California Blvd., Pasadena, CA, 91125 (United States)

    2014-11-01

    Radio-loud active galactic nuclei (AGN) are expected to contribute substantially to both the intensity and anisotropy of the isotropic ?-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 ?-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.

  15. Fermi point in graphene as a monopole in momentum space

    E-Print Network [OSTI]

    M . A. Zubkov

    2011-12-15

    We consider the effective field theory of graphene monolayer with the Coulomb interaction between fermions taken into account. The gauge field in momentum space is introduced. The position of the Fermi point coincides with the position of the corresponding monopole. The procedure of extracting such monopoles during lattice simulations is suggested.

  16. Fermi large area telescope detection of a break in the gamma-ray spectrum of the supernova remnant Cassiopeia A

    SciTech Connect (OSTI)

    Yuan, Yajie; Funk, Stefan; Lande, Joshua; Tibaldo, Luigi [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); Jóhannesson, Gülauger [Science Institute, University of Iceland, IS-107 Reykjavik (Iceland); Uchiyama, Yasunobu, E-mail: yuanyj@stanford.edu, E-mail: funk@slac.stanford.edu, E-mail: joshualande@gmail.com, E-mail: uchiyama@slac.stanford.edu [3-34-1 Nishi-Ikebukuro, Toshima-ku, Tokyo 171-8501 (Japan)

    2013-12-20

    We report on observations of the supernova remnant Cassiopeia A in the energy range from 100 MeV to 100 GeV using 44 months of observations from the Large Area Telescope on board the Fermi Gamma-Ray Space Telescope. We perform a detailed spectral analysis of this source and report on a low-energy break in the spectrum at 1.72{sub ?0.89}{sup +1.35} GeV. By comparing the results with models for the gamma-ray emission, we find that hadronic emission is preferred for the GeV energy range.

  17. Fermi National Accelerator Laboratory August 2015

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

    one-eighth of the southern sky, recording information on 300 million galaxies, 100,000 galaxy clusters and 4,000 supernovae. The Dark Energy Survey is a collaborative effort...

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

    SciTech Connect (OSTI)

    Tanaka, T.; Allafort, A.; Ballet, J.; Funk, S.; Giordano, F.; Hewitt, J.; Lemoine-Goumard, M.; Tajima, H.; Tibolla, O.; Uchiyama, Y.; /Stanford U., HEPL /KIPAC, Menlo Park

    2011-12-13

    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.

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

    SciTech Connect (OSTI)

    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)

    2012-05-10

    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.

  20. A deep view of the Large Magellanic Cloud with 6 years of Fermi-LAT observations

    E-Print Network [OSTI]

    ,

    2015-01-01

    The nearby Large Magellanic Cloud (LMC) provides a rare opportunity for a spatially resolved view of an external star-forming galaxy in gamma-rays. At 0.1-100GeV energies, it was detected as an extended source with CGRO/EGRET and using early observations with the Fermi-LAT. The emission was found to correlate with massive star-forming regions and to be particularly bright towards 30 Doradus. Studies of the origin and transport of cosmic rays (CRs) in the Milky Way are frequently hampered by line-of-sight confusion and poor distance determination. The LMC offers a complementary way to address these questions, by revealing if and how the gamma-ray emission is connected to specific objects, populations of objects, and structures in the galaxy. We revisit the gamma-ray emission from the LMC using about 73 months of Fermi-LAT P7REP data in the 0.2-100GeV range. A complete spatial and spectral model of the LMC emission is developed. Several approaches are tested: a simple geometrical description, template-fitting, ...

  1. Quantification of the Potential Energy

    E-Print Network [OSTI]

    Columbia University

    Quantification of the Potential Energy from Residuals (EfR) in the UK Commissioned, by virtue of its biomass content, it can make a valuable contribution towards our renewable energy targets1 waste up to 2020. To determine the potential2 contribution that energy recovery from residual

  2. U.S. Department of Energy Fermi National Accelerator Laboratory |

    Office of Environmental Management (EM)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of Natural GasAdjustmentsShirley Ann Jackson About1996HowFOAShowing YouNeed forUnruhDepartment ofM ICharterMarch 10,Department

  3. Energy Secretary Moniz to Present Enrico Fermi Awards | Department of

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of Natural GasAdjustmentsShirley Ann JacksonDepartment ofOffice ofofWind ProjectsEfficiency CompetitionEfficientDepartment

  4. A Southern Sky Survey with Fermi LAT and ASKAP

    SciTech Connect (OSTI)

    Cameron, Robert A.; /SLAC /KIPAC, Menlo Park

    2010-04-29

    We present the prospects for a future joint gamma-ray and radio survey of southern hemisphere sources using the Fermi Large Area Telescope (LAT) and the upcoming Australian Square Kilometre Array Pathfinder (ASKAP) radio telescope. ASKAP is a next generation radio telescope designed to perform surveys at GHz frequencies at a much higher survey speed than previous radio telescopes, and is scheduled to start engineering observations in 2011. The survey capabilities of both Fermi LAT and ASKAP are described, and the planned science surveys for ASKAP are summarized. We give some expected details of the Variable and Slow Transient (VAST) survey using ASKAP, which will search for transients on timescales from 5 seconds to years. Some observational properties of faint and transient sources seen at gamma-ray and radio wavelengths are summarized, and prospects and strategies for using ASKAP survey data for LAT source counterpart identification are summarized.

  5. Prospects for GRB Science with the Fermi Large Area Telescope

    E-Print Network [OSTI]

    Band, D L; Baldini, L; Barbiellini, G; Baring, M G; Bastieri, D; Battelino, M; Bellazzini, R; Bissaldi, E; Bogaert, G; Bonnel, J; Chiang, J; Cohen-Tanugi, J; Connaughton, V; Cutini, S; de Palma, F; Dingus, B L; Silva, E do Couto e; Fishman, G; Galli, A; Gehrels, N; Giglietto, N; Granot, J; Guiriec, S; Hughes, R E; Kamae, T; Komin, N; Kühn, F; Kuss, M; Longo, F; Lubrano, P; Kippen, R M; Mazziotta, M N; McEnery, J E; McGlynn, S; Moretti, E; Nakamori, T; Norris, J P; Ohno, M; Olivo, M; Omodei, N; Pelassa, V; Piron, F; Preece, R; Razzano, M; Russell, J J; Ryde, F; Parkinson, P M Saz; Scargle, J D; Sgrò, C; Shimokawabe, T; Smith, P D; Spandre, G; Spinelli, P; Stamatikos, M; Winer, B L; Yamazaki, R

    2009-01-01

    The LAT instrument on the Fermi mission will reveal the rich spectral and temporal gamma-ray burst phenomena in the > 100 MeV band. The synergy with Fermi's GBM detectors will link these observations to those in the well explored 10-1000 keV range; the addition of the > 100 MeV band observations will resolve theoretical uncertainties about burst emission in both the prompt and afterglow phases. Trigger algorithms will be applied to the LAT data both onboard the spacecraft and on the ground. The sensitivity of these triggers will differ because of the available computing resources onboard and on the ground. Here we present the LAT's burst detection methodologies and the instrument's GRB capabilities.

  6. Ratchetlike pulse controlling the Fermi deceleration and hyperacceleration

    E-Print Network [OSTI]

    Cesar Manchein; Marcus W. Beims

    2009-02-28

    Using an ac driven asymmetric pulse we show how the Fermi acceleration (deceleration) can be controlled. A {\\it deformed} sawtooth (Ratchetlike) pulse representing the moving wall in the static Fermi-Ulam model is considered. The time integral from the pulse over one period of oscillation must be negative to obtain deceleration and positive to obtain hyperacceleration. We show that while the decelerated case is chaotic, for the hyperaccelerated case the Lyapunov exponents converge to zero. Numerical simulations indicate that the hyperaccelerated case is ergodic in velocity space. Switching between different pulse deformations we are able to control the particle acceleration. Results should be valid for any pulse for which the time integral can be manipulated between positive and negative values.

  7. Realization of SU(2)*SU(6) Fermi System

    E-Print Network [OSTI]

    Taie, Shintaro; Sugawa, Seiji; Yamazaki, Rekishu; Tsujimoto, Takuya; Murakami, Ryo; Takahashi, Yoshiro

    2010-01-01

    We report the realization of a novel degenerate Fermi mixture with an SU(2)*SU(6) symmetry in a cold atomic gas. We successfully cool the mixture of the two fermionic isotopes of ytterbium 171Yb with the nuclear spin I=1/2 and 173Yb with I=5/2 below the Fermi temperature T_ F as 0.46T_F for 171Yb and 0.54T_F for 173Yb. The same scattering lengths for different spin components make this mixture featured with the novel SU(2)*SU(6) symmetry. The nuclear spin components are separately imaged by exploiting an optical Stern-Gerlach effect. In addition, the mixture is loaded into a 3D optical lattice to implement the SU(2)*SU(6) Hubbard model. This mixture will open the door to the study of novel quantum phases such as a spinor Bardeen-Cooper-Schrieffer-like fermionic superfluid.

  8. I Fermi National Accelerator Laboratory I I

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration would likeUniverse (JournalvivoHighHussein KhalilResearch &ENERGY I NFRASTRUCTURE - _-f;b

  9. Enrico Fermi: Audio/Video Clips

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration would like submitKansasCommunities EnergyU.S.Engineering Metal(2) Cu (3)

  10. Fermi Solar Flare Observations We propose to continue and expand our work over the last three years to make Fermi solar flare

    E-Print Network [OSTI]

    Nishikawa, Ken-Ichi

    1 Fermi Solar Flare Observations 1. Summary We propose to continue and expand our work over the last three years to make Fermi solar flare data readily available for analysis by the international solar physics community. The two-year time frame of the proposed effort is extremely important for solar

  11. Fermi level pinning in Fe-doped PbTe under pressure

    SciTech Connect (OSTI)

    Skipetrov, E. P. Kruleveckaya, O. V.; Skipetrova, L. A.; Slynko, E. I.; Slynko, V. E.

    2014-07-14

    We synthesize an iron-doped PbTe single-crystal ingot and investigate the phase and the elemental composition as well as galvanomagnetic properties in weak magnetic fields (4.2?K?T?300?K, B???0.07?T) of Pb{sub 1?y}Fe{sub y}Te alloys upon varying the iron content, at atmospheric pressure and under hydrostatic compression up to 10 kilobars. We find an increase of iron concentration along the length of the ingot and the appearance of microscopic inclusions enriched with iron in the heavily doped samples. Lightly doped alloys are characterized by the p-type metal conductivity. An increase of the iron impurity content leads to a decrease in the free hole concentration, a stabilization of galvanomagnetic parameters, indicating the pinning of the Fermi energy by the iron resonant impurity level lying under the bottom of the valence band, and to the p-n inversion of the conductivity type. Under pressure, the free hole concentration in the sample, in which the stabilization of galvanomagnetic parameters takes place, increases by approximately a factor of four due to the flow of electrons from the valence band to the iron-induced resonant level. Using the two-band Kane and the six-band Dimmock dispersion relations, the pressure dependence of the Fermi energy is calculated. The model of the electronic structure rearrangement of Pb{sub 1?y}Fe{sub y}Te under pressure is proposed. The energy position and the pressure coefficient of the resonant iron impurity level are determined.

  12. Jet emission in young radio sources: A Fermi large area telescope gamma-ray view

    SciTech Connect (OSTI)

    Migliori, G.; Siemiginowska, A.; Kelly, B. C.; Stawarz, ?.; Celotti, A.; Begelman, M. C.

    2014-01-10

    We investigate the contribution of the beamed jet component to the high-energy emission in young and compact extragalactic radio sources, focusing for the first time on the ?-ray band. We derive predictions on the ?-ray luminosities associated with the relativistic jet assuming a leptonic radiative model. The high-energy emission is produced via Compton scattering by the relativistic electrons in a spherical region at the considered scales (?10 kpc). Simulations show a wide range of ?-ray luminosities, with intensities up to ?10{sup 46}-10{sup 48} erg s{sup –1} depending on the assumed jet parameters. We find a highly linear relation between the simulated X-ray and ?-ray luminosities that can be used to select candidates for ?-ray detection. We compare the simulated luminosity distributions in the radio, X-ray, and ?-ray regimes with observations for the largest sample of X-ray-detected young radio quasars. Our analysis of ?4-yr Fermi Large Area Telescope (LAT) data does not yield any statistically significant detections. However, the majority of the model-predicted ?-ray fluxes for the sample are near or below the current Fermi-LAT flux threshold and compatible with the derived upper limits. Our study gives constraints on the minimum jet power (L {sub jet,} {sub kin}/L {sub disk} > 0.01) of a potential jet contribution to the X-ray emission in the most compact sources (? 1 kpc) and on the particle-to-magnetic field energy density ratio that are in broad agreement with equipartition assumptions.

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

    E-Print Network [OSTI]

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

    2014-06-16

    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.

  14. First results on Cosmic Ray electron spectrum below 20 GeV from the Fermi LAT

    E-Print Network [OSTI]

    Pesce-Rollins, Melissa

    2009-01-01

    Designed to be a successor of the previous flown space based gamma ray detectors, the Fermi Large Area Telescope (LAT) is also an electron detector. Taking advantage of its capability to separate electromagnetic and hadronic signals it is possible to accurately measure the Cosmic Ray electron spectrum. The spectra of primary cosmic ray electrons below 20 GeV is influenced by many local effects such as solar modulation and the geomagnetic cutoff. For energies below a few GeV it is possible to observe the albedo population of electrons which are controlled by the local magnetic field. In this paper we present the LAT electron analysis in particular event selection and validation as well as the first results on the measurement of the electron spectrum below 20 GeV.

  15. FERMI LIMIT ON THE NEUTRINO FLUX FROM GAMMA-RAY BURSTS

    SciTech Connect (OSTI)

    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)

    2013-06-20

    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.

  16. Fermi Limit on the Neutrino Flux from Gamma-ray Bursts

    E-Print Network [OSTI]

    Zhuo Li

    2013-06-14

    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.

  17. A quantum kinetic equation for Fermi-systems including three-body correlations

    E-Print Network [OSTI]

    A. Sedrakian; G. Roepke

    1998-04-23

    A single-time quantum transport equation, which includes effects beyond the quasiparticle approximation, is derived for Fermi-systems in the framework of non-equilibrium real-time Green's functions theory. Ternary correlations are incorporated in the kinetic description via a cluster expansion for the self-energies (e.g., the transport vertex and the width) truncated at the level of three-body scattering amplitudes. A finite temperature/density formulation of the three-body problem is given. Corresponding three-body equations reduce to the well-known Faddeev equations in the vacuum limit. In equilibrium the equation of state contains virial corrections proportional to the third quantum virial coefficient.

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

    SciTech Connect (OSTI)

    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)

    2014-10-15

    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.

  19. Non-Fermi-Liquid Specific Heat of Normal Degenerate Quark Matter

    E-Print Network [OSTI]

    A. Gerhold; A. Ipp; A. Rebhan

    2004-08-31

    We compute the low-temperature behavior of the specific heat of normal (non-color-superconducting) degenerate quark matter as well as that of an ultradegenerate electron gas. Long-range magnetic interactions lead to non-Fermi-liquid behavior with an anomalous leading $T\\ln T^{-1}$ term. Depending on the thermodynamic potential used as starting point, this effect appears as a consequence of the logarithmic singularity in the fermion self-energy at the Fermi surface or directly as a contribution from the only weakly screened quasistatic magnetic gauge bosons. We show that a calculation of Boyanovsky and de Vega claiming the absence of a leading $T\\ln T^{-1}$ term missed it by omitting vector boson contributions to the internal energy. Using a formulation which collects all nonanalytic contributions in bosonic ring diagrams, we systematically calculate corrections beyond the well-known leading-log approximation. The higher-order terms of the low-temperature expansion turn out to also involve fractional powers $T^{(3+2n)/3}$ and we explicitly determine their coefficients up to and including order $T^{7/3}$ as well as the subsequent logarithmically enhanced term $T^3 \\ln (c/T)$. We derive also a hard-dense-loop resummed expression which contains the infinite series of anomalous terms to leading order in the coupling and which we evaluate numerically. At low temperatures, the resulting deviation of the specific heat from its value in naive perturbation theory is significant in the case of strongly coupled normal quark matter and thus of potential relevance for the cooling rates of (proto-)neutron stars with a quark matter component.

  20. Dual vortex theory of strongly interacting electrons: A non-Fermi...

    Office of Scientific and Technical Information (OSTI)

    Dual vortex theory of strongly interacting electrons: A non-Fermi liquid with a twist Citation Details In-Document Search Title: Dual vortex theory of strongly interacting...

  1. FERMI-LAT DETECTION OF PULSED GAMMA-RAYS ABOVE 50 GeV FROM THE VELA PULSAR

    SciTech Connect (OSTI)

    Leung, Gene C. K.; Takata, J.; Ng, C. W.; Cheng, K. S. [Department of Physics, The University of Hong Kong, Pokfulam Road (Hong Kong); Kong, A. K. H.; Tam, P. H. T. [Institute of Astronomy and Department of Physics, National Tsing Hua University, Hsinchu, Taiwan (China); Hui, C. Y., E-mail: gene930@connect.hku.hk, E-mail: takata@hku.hk [Department of Astronomy and Space Science, Chungnam National University, Daejeon (Korea, Republic of)

    2014-12-20

    The first Fermi-Large Area Telescope (LAT) catalog of sources above 10 GeV reported evidence of pulsed emission above 25 GeV from 12 pulsars, including the Vela pulsar, which showed evidence of pulsation at >37 GeV energy bands. Using 62 months of Fermi-LAT data, we analyzed the gamma-ray emission from the Vela pulsar and searched for pulsed emission above 50 GeV. Having confirmed the significance of the pulsation in 30-50 GeV with the H test (p-value ?10{sup –77}), we extracted its pulse profile using the Bayesian block algorithm and compared it with the distribution of the five observed photons above 50 GeV using the likelihood ratio test. Pulsation was significantly detected for photons above 50 GeV with a p-value of =3 × 10{sup –5} (4.2?). The detection of pulsation is significant above 4? at >79 GeV and above 3? at >90 GeV energy bands, making this the highest energy pulsation significantly detected by the LAT. We explore the non-stationary outer gap scenario of the very high-energy emissions from the Vela pulsar.

  2. Bifurcation in kinetic equation for interacting Fermi systems

    E-Print Network [OSTI]

    Klaus Morawetz

    2003-01-27

    The finite duration of collisions appear as time-nonlocality in the kinetic equation. Analyzing the corresponding quantum kinetic equation for dense interacting Fermi systems a delay differential equation is obtained which combines time derivatives with finite time stepping known from the logistic mapping. The responsible delay time is explicitly calculated and discussed. As a novel feature oscillations in the time evolution of the distribution function itself appear and bifurcations up to chaotic behavior can occur. The temperature and density conditions are presented where such oscillations and bifurcations arise indicating an onset of phase transition.

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

    Office of Legacy Management (LM)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefield Municipal Gas &SCE-SessionsSouth Dakota Edgemont, SouthLaboratoryDiv - NYCorp- 016 Fermi

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

    SciTech Connect (OSTI)

    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.

    2010-05-26

    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.

  5. Exploring the Thermodynamics of a Universal Fermi Gas

    E-Print Network [OSTI]

    Nascimbène, Sylvain; Jiang, Kaijun; Chevy, Frédéric; Salomon, Christophe; 10.1038/nature08814

    2010-01-01

    From sand piles to electrons in metals, one of the greatest challenges in modern physics is to understand the behavior of an ensemble of strongly interacting particles. A class of quantum many-body systems such as neutron matter and cold Fermi gases share the same universal thermodynamic properties when interactions reach the maximum effective value allowed by quantum mechanics, the so-called unitary limit [1,2]. It is then possible to simulate some astrophysical phenomena inside the highly controlled environment of an atomic physics laboratory. Previous work on the thermodynamics of a two-component Fermi gas led to thermodynamic quantities averaged over the trap [3-5], making it difficult to compare with many-body theories developed for uniform gases. Here we develop a general method that provides for the first time the equation of state of a uniform gas, as well as a detailed comparison with existing theories [6,14]. The precision of our equation of state leads to new physical insights on the unitary gas. F...

  6. Simulating strongly correlated electrons with a strongly interacting Fermi gas

    SciTech Connect (OSTI)

    Thomas, John E. [North Carolina State University

    2013-05-28

    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.

  7. FermiQCD: A tool kit for parallel lattice QCD applications

    E-Print Network [OSTI]

    Massimo Di Pierro

    2001-10-15

    We present here the most recent version of FermiQCD, a collection of C++ classes, functions and parallel algorithms for lattice QCD, based on Matrix Distributed Processing. FermiQCD allows fast development of parallel lattice applications and includes some SSE2 optimizations for clusters of Pentium 4 PCs.

  8. Multipole Representation of the Fermi Operator with Application to the Electronic Structure Analysis of Metallic Systems

    E-Print Network [OSTI]

    Lu, Jianfeng

    Multipole Representation of the Fermi Operator with Application to the Electronic Structure Analysis of Metallic Systems Lin Lin and Jianfeng Lu Program in Applied and Computational Mathematics and the Fermi operator, and use this representation to develop algorithms for electronic structure analysis

  9. Corrections to Thomas-Fermi Densities at Turning Points and Beyond Raphael F. Ribeiro,1

    E-Print Network [OSTI]

    Burke, Kieron

    Corrections to Thomas-Fermi Densities at Turning Points and Beyond Raphael F. Ribeiro,1 Donghyung Lee,2 Attila Cangi,3 Peter Elliott,3 and Kieron Burke1 1 Department of Chemistry, University corrections to Thomas-Fermi theory, involve neither sums nor derivatives, are spatially uniform approximations

  10. LE JOURNAL DE PHYSIQUE Generalization of the Fermi-Segr formula

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    1491 LE JOURNAL DE PHYSIQUE Generalization of the Fermi-Segrè formula N. Frôman and P. O. Fröman. 2014 A generalization of the non-relativistic Fermi-Segrè formula into a formula which is valid also. The formula thus obtained, which gives an expression for the limit of u(r)/rl+ 1 as r ~ 0, where u

  11. Influence of Induced Interactions on the Superfluid Transition in Dilute Fermi Gases

    E-Print Network [OSTI]

    H. Heiselberg; C. J. Pethick; H. Smith; L. Viverit

    2000-04-20

    We calculate the effects of induced interactions on the transition temperature to the BCS state in dilute Fermi gases. For a pure Fermi system with 2 species having equal densities, the transition temperature is suppressed by a factor $(4e)^{1/3}\\approx 2.2$, and for $\

  12. Fermi Surface of Uranium at Ambient Pressure Gregory S. Boebinger, National High Magnetic Field Laboratory

    E-Print Network [OSTI]

    Weston, Ken

    Fermi Surface of ­Uranium at Ambient Pressure Gregory S. Boebinger, National High Magnetic Field Laboratory DMR-Award 0654118 DC Field Facility User Program The fermi surface of ­Uranium has been measured surface of alpha-uranium at ambient pressure, Phys. Rev. B Rapid Commun., 80, 241101 (2009). B//c-axis B

  13. THE SECOND STAGE OF FERMI@ELETTRA: A SEEDED FEL IN THE SOFT X-RAY SPECTRAL RANGE

    E-Print Network [OSTI]

    Allaria, E.

    2010-01-01

    OF FERMI@ELETTRA: A SEEDED FEL IN THE SOFT X-RAY SPECTRALTrieste, Italy. Abstract The second stage of the FERMI FEL,named FEL-2, is based on the principle of high-gain harmonic

  14. Finite range and upper branch effects on itinerant ferromagnetism in repulsive Fermi gases: Bethe–Goldstone ladder resummation approach

    SciTech Connect (OSTI)

    He, Lianyi

    2014-12-15

    We investigate the ferromagnetic transition in repulsive Fermi gases at zero temperature with upper branch and effective range effects. Based on a general effective Lagrangian that reproduces precisely the two-body s-wave scattering phase shift, we obtain a nonperturbative expression of the energy density as a function of the polarization by using the Bethe–Goldstone ladder resummation. For hard sphere potential, the predicted critical gas parameter k{sub F}a=0.816 and the spin susceptibility agree well with the results from fixed-node diffusion Monte Carlo calculations. In general, positive and negative effective ranges have opposite effects on the critical gas parameter k{sub F}a: While a positive effective range reduces the critical gas parameter, a negative effective range increases it. For attractive potential or Feshbach resonance model, the many-body upper branch exhibits an energy maximum at k{sub F}a=? with ?=1.34 from the Bethe–Goldstone ladder resummation, which is qualitatively consistent with experimental results. The many-body T-matrix has a positive-energy pole for k{sub F}a>? and it becomes impossible to distinguish the bound state and the scattering state. These positive-energy bound states become occupied and therefore the upper branch reaches an energy maximum at k{sub F}a=?. In the zero range limit, there exists a narrow window (0.86energy bound state resonantly enhances the two-body decay rate around k{sub F}a=? and may prevent the study of equilibrium phases and ferromagnetism of the upper branch Fermi gas. - Highlights: • Nonperturbative interaction energy is obtained within the Bethe–Goldstone ladder resummation approach. • Positive and negative effective ranges have opposite effects on the critical gas parameter. • The upper branch Fermi gas exhibits an energy maximum and reentrant ferromagnetic transition. • The ferromagnetic phase disappears for large and negative effective ranges.

  15. Stochastic Fermi Acceleration of sub-Relativistic Electrons and Its Role in Impulsive Solar Flares

    E-Print Network [OSTI]

    Robert Selkowitz; Eric G. Blackman

    2004-07-23

    We reexamine stochastic Fermi acceleration (STFA) in the low energy (Newtonian) regime in the context of solar flares. The particle energization rate depends a dispersive term and a coherent gain term. The energy dependence of pitch angle scattering is important for determining the electron energy spectrum. For scattering by whistler wave turbulence, STFA produces a quasi-thermal spectrum. A second well-constrained scattering mechanism is needed for STFA to match the observed 10-100keV non-thermal spectrum. We suggest that STFA most plausibly acts as phase one of a two phase particle acceleration engine in impulsive flares: STFA can match the thermal spectrum below 10kev, and possibly the power law spectrum between 10 and 100keV, given the proper pitch angle scattering. However, a second phase, such as shock acceleration at loop tops, is likely required to match the spectrum above the observed knee at 100keV. Understanding this knee, if it survives further observations, is tricky.

  16. Stochastic Fermi Acceleration of sub-Relativistic Electrons and Its Role in Impulsive Solar Flares

    E-Print Network [OSTI]

    Selkowitz, R; Selkowitz, Robert; Blackman, Eric G.

    2004-01-01

    We reexamine stochastic Fermi acceleration (STFA) in the low energy (Newtonian) regime in the context of solar flares. The particle energization rate depends a dispersive term and a coherent gain term. The energy dependence of pitch angle scattering is important for determining the electron energy spectrum. For scattering by whistler wave turbulence, STFA produces a quasi-thermal spectrum. A second well-constrained scattering mechanism is needed for STFA to match the observed 10-100keV non-thermal spectrum. We suggest that STFA most plausibly acts as phase one of a two phase particle acceleration engine in impulsive flares: STFA can match the thermal spectrum below 10kev, and possibly the power law spectrum between 10 and 100keV, given the proper pitch angle scattering. However, a second phase, such as shock acceleration at loop tops, is likely required to match the spectrum above the observed knee at 100keV. Understanding this knee, if it survives further observations, is tricky.

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

    E-Print Network [OSTI]

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

    2014-12-02

    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.

  18. Local H~{\\sc i} emissivity measured with the {\\it Fermi}-LAT and implications for cosmic-ray spectra

    E-Print Network [OSTI]

    Casandjian, Jean-Marc

    2015-01-01

    Cosmic-ray (CR) electrons and nuclei interact with the Galactic interstellar gas and produce high-energy $\\gamma$ rays. The $\\gamma$-ray emission rate per hydrogen atom, called emissivity, provides a unique indirect probe of the CR flux. We present the measurement and the interpretation of the emissivity in the solar neighborhood for $\\gamma$-ray energy from 50~MeV to 50~GeV. We analyzed a subset of 4 years of observations from the Large Area Telescope (LAT) aboard the {\\it Fermi Gamma-ray Space Telescope} ({\\it Fermi}) restricted to absolute latitudes $10^ohydrogen column density templates as well as a dust optical depth map we derived the emissivities, the molecular hydrogen to CO conversion factor $X_{CO}=(0.902\\pm0.007) \\times 10^{20}$ cm$^{-2}$ (K km s$^{-1}$)$^{-1}$ and the dust-to-gas ratio $X_{DUST}=(41.4\\pm0.3) \\times 10^{20}$ cm$^{-2}$ mag$^{-1}$. Moreover we detected for the first time $\\gamma$-ray emission from i...

  19. Elliptic flow and nearly perfect fluidity in dilute Fermi gases

    E-Print Network [OSTI]

    Thomas Schaefer

    2010-12-16

    In this contribution we summarize recent progress in understanding the shear viscosity of strongly correlated dilute Fermi gases. We discuss predictions from kinetic theory, and show how these predictions can be tested using recent experimental data on elliptic flow. We find agreement between theory and experiments in the high temperature regime $T\\gg T_F$, where $T_F$ is the the temperature where quantum degeneracy effects become important. In the low temperature regime, $T\\sim T_F$, the strongest constraints on the shear viscosity come from experimental studies of the damping of collective modes. These experiments indicate that $\\eta/s\\lsim 0.5\\hbar/k_B$, where $\\eta$ is the shear viscosity and $s$ is the entropy density.

  20. Fermi GBM Observations of Terrestrial Gamma-ray Flashes

    SciTech Connect (OSTI)

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

    2011-09-21

    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.

  1. Probing the gamma-ray emission from HESS J1834-087 using H.E.S.S. and Fermi LAT observations

    E-Print Network [OSTI]

    :,; Aharonian, F; Benkhali, F Ait; Akhperjanian, A G; Angüner, E; Anton, G; Backes, M; Balenderan, S; Balzer, A; Barnacka, A; Becherini, Y; Tjus, J Becker; Bernlöhr, K; Birsin, E; Bissaldi, E; Biteau, J; Böttcher, M; Boisson, C; Bolmont, J; Bordas, P; Brucker, J; Brun, F; Brun, P; Bulik, T; Carrigan, S; Casanova, S; Chadwick, P M; Chalme-Calvet, R; Chaves, R C G; Cheesebrough, A; Chrétien, M; Colafrancesco, S; Cologna, G; Conrad, J; Couturier, C; Cui, Y; Dalton, M; Daniel, M K; Davids, I D; Degrange, B; Deil, C; deWilt, P; Dickinson, H J; Djannati-Ataï, A; Domainko, W; Drury, L O'C; Dubus, G; Dutson, K; Dyks, J; Dyrda, M; Edwards, T; Egberts, K; Eger, P; Espigat, P; Farnier, C; Fegan, S; Feinstein, F; Fernandes, M V; Fernandez, D; Fiasson, A; Fontaine, G; Förster, A; Füßling, M; Gajdus, M; Gallant, Y A; Garrigoux, T; Giavitto, G; Giebels, B; Glicenstein, J F; Grondin, M -H; Grudzi?ska, M; Häffner, S; Hahn, J; Harris, J; Heinzelmann, G; Henri, G; Hermann, G; Hervet, O; Hillert, A; Hinton, J A; Hofmann, W; Hofverberg, P; Holler, M; Horns, D; Jacholkowska, A; Jahn, C; Jamrozy, M; Janiak, M; Jankowsky, F; Jung, I; Kastendieck, M A; Katarzy?ski, K; Katz, U; Kaufmann, S; Khélifi, B; Kieffer, M; Klepser, S; Klochkov, D; Klu?niak, W; Kneiske, T; Kolitzus, D; Komin, Nu; Kosack, K; Krakau, S; Krayzel, F; Krüger, P P; Laffon, H; Lamanna, G; Lefaucheur, J; Lemière, A; Lemoine-Goumard, M; Lenain, J -P; Lohse, T; Lopatin, A; Lu, C -C; Marandon, V; Marcowith, A; Marx, R; Maurin, G; Maxted, N; Mayer, M; McComb, T J L; Méhault, J; Meintjes, P J; Menzler, U; Meyer, M; Moderski, R; Mohamed, M; Moulin, E; Murach, T; Naumann, C L; de Naurois, M; Niemiec, J; Nolan, S J; Oakes, L; Odaka, H; Ohm, S; Wilhelmi, E de Oña; Opitz, B; Ostrowski, M; Oya, I; Panter, M; Parsons, R D; Arribas, M Paz; Pekeur, N W; Pelletier, G; Perez, J; Petrucci, P -O; Peyaud, B; Pita, S; Poon, H; Pühlhofer, G; Punch, M; Quirrenbach, A; Raab, S; Raue, M; Reichardt, I; Reimer, A; Reimer, O; Renaud, M; Reyes, R de los; Rieger, F; Rob, L; Romoli, C; Rosier-Lees, S; Rowell, G; Rudak, B; Rulten, C B; Sahakian, V; Sanchez, D A; Santangelo, A; Schlickeiser, R; Schüssler, F; Schulz, A; Schwanke, U; Schwarzburg, S; Schwemmer, S; Sol, H; Spengler, G; Spies, F; Stawarz, ?; Steenkamp, R; Stegmann, C; Stinzing, F; Stycz, K; Sushch, I; Tavernet, J -P; Tavernier, T; Taylor, A M; Terrier, R; Tluczykont, M; Trichard, C; Valerius, K; van Eldik, C; van Soelen, B; Vasileiadis, G; Venter, C; Viana, A; Vincent, P; Völk, H J; Volpe, F; Vorster, M; Vuillaume, T; Wagner, S J; Wagner, P; Wagner, R M; Ward, M; Weidinger, M; Weitzel, Q; White, R; Wierzcholska, A; Willmann, P; Wörnlein, A; Wouters, D; Yang, R; Zabalza, V; Zacharias, M; Zdziarski, A A; Zech, A; Zechlin, H -S; Acero, F; Casandjian, J M; Cohen-Tanugi, J; Giordano, F; Guillemot, L; Lande, J; Pletsch, H; Uchiyama, Y

    2014-01-01

    Previous observations with HESS have revealed the existence of an extended very-high-energy (VHE; E>100 GeV) gamma-ray source, HESS J1834-087, coincident with the SNR W41. The origin of the gamma-ray emission has been further investigated with HESS and the Fermi-LAT. The gamma-ray data provided by 61h (HESS) and 4 yrs (Fermi LAT) of observations cover over 5 decades in energy (1.8GeV - 30TeV). The morphology and spectrum of the TeV and GeV sources have been studied and multi-wavelength data have been used to investigate the origin of the observed emission. The TeV source can be modeled with a sum of two components: one point-like and one significantly extended (sig_TeV = 0.17{\\deg}), both centered on SNR W41 and exhibiting spectra described by a power law of index 2.6. The GeV source detected with Fermi is extended (sig_GeV =0.15{\\deg}) and morphologically matches the VHE emission. Its spectrum can be described by a power-law with index 2.15 and joins smoothly the one of the whole TeV source. A break appears ...

  2. Fermi arc topology and interconnectivity in Weyl fermion semimetals TaAs, TaP, NbAs, and NbP

    E-Print Network [OSTI]

    Chi-Cheng Lee; Su-Yang Xu; Shin-Ming Huang; Daniel S. Sanchez; Ilya Belopolski; Guoqing Chang; Guang Bian; Nasser Alidoust; Hao Zheng; Madhab Neupane; Baokai Wang; Arun Bansil; M. Zahid Hasan; Hsin Lin

    2015-08-24

    The family of binary compounds including TaAs, TaP, NbAs, and NbP was recently discovered as the first realization of Weyl semimetals. In order to develop a comprehensive description of the charge carriers in these Weyl semimetals, we performed systematic electronic structure calculations which reveal the nature of Fermi surfaces and their complex interconnectivity in TaAs, TaP, NbAs, and NbP. Our work report the first comparative and comprehensive study of Fermi surface topology and band structure details of all known members of the Weyl semimetal family and provide the necessary building blocks for advancing our understanding of their unique topologically protected low-energy Weyl fermion physics.

  3. Spectral analysis of Fermi-LAT blazars above 50 GeV

    E-Print Network [OSTI]

    Domínguez, Alberto

    2015-01-01

    We present an analysis of the intrinsic (unattenuated by the extragalactic background light, EBL) power-law spectral indices of 128 extragalactic sources detected up to z~2 with the Fermi-Large Area Telescope (LAT) at very high energies (VHEs, E>50 GeV). The median of the intrinsic index distribution is 2.20 (versus 2.54 for the observed distribution). We also analyze the observed spectral breaks (i.e., the difference between the VHE and high energy, HE, 100 MeV

  4. UNEP Rise Centre Energy, Climate and Sustainable

    E-Print Network [OSTI]

    ·Development of a pipeline of potential CDM projects ·Development of analytical guidelines and training courses Secretariat in Brussels. #12;Development and Energy in Africa (DEA) · A project of the EC COOPENER Programme Project sponsored by Dutch Government with US$10 million #12;Energy for Development (EfD) Network

  5. Search for Spatially Extended Fermi-LAT Sources Using Two Years of Data

    SciTech Connect (OSTI)

    Lande, Joshua; Ackermann, Markus; Allafort, Alice; Ballet, Jean; Bechtol, Keith; Burnett, Toby; Cohen-Tanugi, Johann; Drlica-Wagner, Alex; Funk, Stefan; Giordano, Francesco; Grondin, Marie-Helene; Kerr, Matthew; Lemoine-Goumard, Marianne

    2012-07-13

    Spatial extension is an important characteristic for correctly associating {gamma}-ray-emitting sources with their counterparts at other wavelengths and for obtaining an unbiased model of their spectra. We present a new method for quantifying the spatial extension of sources detected by the Large Area Telescope (LAT), the primary science instrument on the Fermi Gamma-ray Space Telescope (Fermi). We perform a series of Monte Carlo simulations to validate this tool and calculate the LAT threshold for detecting the spatial extension of sources. We then test all sources in the second Fermi -LAT catalog (2FGL) for extension. We report the detection of seven new spatially extended sources.

  6. Fermi-Boltzmann statistics of neutrinos and relativistic effective degrees of freedom

    E-Print Network [OSTI]

    Jun Iizuka; Teruyuki Kitabayashi

    2014-11-22

    We investigate the effect of the presence of non-pure fermionic neutrinos on the relativistic effective degrees of freedom in the early universe. The statistics of neutrinos is transformed continuously from Fermi-Dirac to Maxwell-Boltzmann statistics. We find that the relativistic degrees of freedom decreases with the deviation from pure Fermi-Dirac statistics of neutrinos if there are constant and large lepton asymmetries. Additionally, we confirm that the change of the statistics of neutrinos from Fermi-Dirac to Maxwell-Boltzmann is not sufficient to cover the excess of the effective number of neutrinos.

  7. On the role of stochastic Fermi acceleration in setting the dissipation scale of turbulence in the interstellar medium

    E-Print Network [OSTI]

    Robert I Selkowitz; Eric G. Blackman

    2007-07-31

    We consider the dissipation by Fermi acceleration of magnetosonic turbulence in the Reynolds Layer of the interstellar medium. The scale in the cascade at which electron acceleration via stochastic Fermi acceleration (STFA) becomes comparable to further cascade of the turbulence defines the inner scale. For any magnetic turbulent spectra equal to or shallower than Goldreich-Sridhar this turns out to be $\\ge 10^{12}$cm, which is much larger than the shortest length scales observed in radio scintillation measurements. While STFA for such spectra then contradict models of scintillation which appeal directly to an extended, continuous turbulent cascade, such a separation of scales is consistent with the recent work of \\citet{Boldyrev2} and \\citet{Boldyrev3} suggesting that interstellar scintillation may result from the passage of radio waves through the galactic distribution of thin ionized boundary surfaces of HII regions, rather than density variations from cascading turbulence. The presence of STFA dissipation also provides a mechanism for the non-ionizing heat source observed in the Reynolds Layer of the interstellar medium \\citep{Reynolds}. STFA accommodates the proper heating power, and the input energy is rapidly thermalized within the low density Reynolds layer plasma.

  8. A method to efficiently simulate the thermodynamical properties of the Fermi-Hubbard model on a quantum computer

    E-Print Network [OSTI]

    Pierre-Luc Dallaire-Demers; Frank K. Wilhelm

    2015-08-18

    Many phenomena of strongly correlated materials are encapsulated in the Fermi-Hubbard model whose thermodynamical properties can be computed from its grand canonical potential according to standard procedures. In general, there is no closed form solution for lattices of more than one spatial dimension, but solutions can be approximated with cluster perturbation theory. To model long-range effects such as order parameters, a powerful method to compute the cluster's Green's function consists in finding its self-energy through a variational principle of the grand canonical potential. This opens the possibility of studying various phase transitions at finite temperature in the Fermi-Hubbard model. However, a classical cluster solver quickly hits an exponential wall in the memory (or computation time) required to store the computation variables. Here it is shown theoretically that that the cluster solver can be mapped to a subroutine on a quantum computer whose quantum memory scales as the number of orbitals in the simulated cluster. A quantum computer with a few tens of qubits could therefore simulate the thermodynamical properties of complex fermionic lattices inaccessible to classical supercomputers.

  9. A method to efficiently simulate the thermodynamical properties of the Fermi-Hubbard model on a quantum computer

    E-Print Network [OSTI]

    Pierre-Luc Dallaire-Demers; Frank K. Wilhelm

    2015-11-27

    Many phenomena of strongly correlated materials are encapsulated in the Fermi-Hubbard model whose thermodynamical properties can be computed from its grand canonical potential according to standard procedures. In general, there is no closed form solution for lattices of more than one spatial dimension, but solutions can be approximated with cluster perturbation theory. To model long-range effects such as order parameters, a powerful method to compute the cluster's Green's function consists in finding its self-energy through a variational principle of the grand canonical potential. This opens the possibility of studying various phase transitions at finite temperature in the Fermi-Hubbard model. However, a classical cluster solver quickly hits an exponential wall in the memory (or computation time) required to store the computation variables. Here it is shown theoretically that that the cluster solver can be mapped to a subroutine on a quantum computer whose quantum memory scales as the number of orbitals in the simulated cluster. A quantum computer with a few tens of qubits could therefore simulate the thermodynamical properties of complex fermionic lattices inaccessible to classical supercomputers.

  10. Study of the Electron Beam Dynamics in the FERMI @ ELETTRA Linac

    E-Print Network [OSTI]

    2006-01-01

    STUDY OF THE ELECTRON BEAM DYNAMICS IN THE FERMI @ ELETTRAAbstract A study of the electron beam dynamics in the linacused to direct the electron beam into one of two undulator

  11. A simple way to the high-temperature expansion of relativistic Fermi-Dirac integrals

    E-Print Network [OSTI]

    Khvorostukhin, A S

    2015-01-01

    The pressure of an ideal relativistic Fermi gas is computed as an infinite series for high temperatures. Expansion of the particle number density, the scalar density, and the entropy density as first derivatives of the pressure is also found.

  12. Collective Modes in a Unitary Fermi Gas across the Superfluid Phase Transition

    E-Print Network [OSTI]

    Tey, Meng Khoon

    We provide a joint theoretical and experimental investigation of the temperature dependence of the collective oscillations of first sound nature exhibited by a highly elongated harmonically trapped Fermi gas at unitarity, ...

  13. Coherent quench dynamics in the one-dimensional Fermi-Hubbard model

    E-Print Network [OSTI]

    Iyer, Deepak

    Recently, it has been shown that the momentum distribution of a metallic state of fermionic atoms in a lattice Fermi-Bose mixture exhibits coherent oscillations after a global quench that suppresses tunneling. The oscillation ...

  14. Physics 112 Mathematical Notes Winter 2000 1. Power Series Expansion of the FermiDirac Integral

    E-Print Network [OSTI]

    California at Santa Cruz, University of

    Physics 112 Mathematical Notes Winter 2000 1. Power Series Expansion of the Fermi­Dirac Integral The Fermi­Dirac integral is defined as: f n (z) # 1 #(n) # # 0 x n-1 dx z -1 e x + 1 , where x # #/kT and z e -(m+1)x x n-1 dx . Using the well known integral: # # 0 e -Ax x n-1 dx = #(n) A n , and changing

  15. Physics 112 Mathematical Notes Winter 2000 1. Power Series Expansion of the Fermi-Dirac Integral

    E-Print Network [OSTI]

    California at Santa Cruz, University of

    Physics 112 Mathematical Notes Winter 2000 1. Power Series Expansion of the Fermi-Dirac Integral The Fermi-Dirac integral is defined as: fn(z) 1 (n) 0 xn-1 dx z-1ex + 1 , where x /kT and z eµ/kT . We (ze-x )m = z (n) m=0 (-1)m zm 0 e-(m+1)x xn-1 dx . Using the well known integral: 0 e-Ax xn-1 dx

  16. Composition of the Fermi-LAT isotropic gamma-ray background intensity: Emission from extragalactic point sources and dark matter annihilations

    E-Print Network [OSTI]

    Mattia Di Mauro; Fiorenza Donato

    2015-06-14

    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 fit to the IGRB data. Our analysis is conducted within the different IGRB data sets obtained from different models for the Galactic emission, which is shown to add a significant ambiguity on the IGRB interpretation.

  17. Implications of plasma beam instabilities for the statistics of the Fermi hard gamma-ray blazars and the origin of the extragalactic gamma-ray background

    SciTech Connect (OSTI)

    Broderick, Avery E. [Perimeter Institute for Theoretical Physics, 31 Caroline Street North, Waterloo, ON N2L 2Y5 (Canada); Pfrommer, Christoph; Puchwein, Ewald [Heidelberg Institute for Theoretical Studies, Schloss-Wolfsbrunnenweg 35, D-69118 Heidelberg (Germany); Chang, Philip [Department of Physics, University of Wisconsin-Milwaukee, 1900 East Kenwood Boulevard, Milwaukee, WI 53211 (United States)

    2014-08-01

    Fermi has been instrumental in constraining the luminosity function and redshift evolution of gamma-ray bright BL Lac objects, a subpopulation of blazars with almost featureless optical spectra. This includes limits on the spectrum and anisotropy of the extragalactic gamma-ray background (EGRB), redshift distribution of nearby Fermi active galactic nuclei (AGNs), and the construction of a logN-log S relation. Based on these, it has been argued that the evolution of the gamma-ray bright BL Lac population must be much less dramatic than that of other AGNs. However, critical to such claims is the assumption that inverse Compton cascades reprocess emission above a TeV into the Fermi energy range, substantially enhancing the strength of the observed limits. Here we demonstrate that in the absence of such a process, due, e.g., to the presence of virulent plasma beam instabilities that preempt the cascade, a population of TeV-bright BL Lac objects that evolve similarly to quasars is consistent with the population of hard gamma-ray BL Lac objects observed by Fermi. Specifically, we show that a simple model for the properties and luminosity function is simultaneously able to reproduce their logN-log S relation, local redshift distribution, and contribution to the EGRB and its anisotropy without any free parameters. Insofar as the naturalness of a picture in which the hard gamma-ray BL Lac population exhibits the strong redshift evolution observed in other tracers of the cosmological history of accretion onto halos is desirable, this lends support for the absence of the inverse Compton cascades and the existence of the beam plasma instabilities.

  18. Hunting for dark matter subhalos among the Fermi-LAT sources with VERITAS

    E-Print Network [OSTI]

    Nieto, Daniel

    2015-01-01

    The distribution of dark matter in the Galaxy, according to state-of-the-art simulations, shows not only a smooth halo component but also a rich substructure where a hierarchy of dark matter subhalos of different masses is found. We present a search for potential dark matter subhalos in our Galaxy exploiting the high (HE, 100 MeV -- 100 GeV) and very-high-energy (VHE, >100 GeV) gamma-ray bands. We assume a scenario where the dark matter is composed of weakly interacting massive particles of mass over 100 GeV, and is capable of self-annihilation into standard model products. Under such a hypothesis, most of the photons created by the annihilation of dark matter particles are predicted to lay in the HE gamma-ray band, where the Fermi-Large Area Telescope is the most sensitive instrument to date. However, the distinctive spectral cut-off located at the dark matter particle mass is expected in the VHE gamma-ray band, thus making imaging atmospheric Cherenkov telescopes like VERITAS the best suited instruments for...

  19. Implications of Fermi-LAT observations on the origin of IceCube neutrinos

    SciTech Connect (OSTI)

    Wang, Bin; Li, Zhuo [Department of Astronomy, School of Physics, Peking University, Beijing (China); Zhao, Xiaohong, E-mail: wang_b@pku.edu.cn, E-mail: zhaoxh@ynao.ac.cn, E-mail: zhuo.li@pku.edu.cn [Yunnan Observatories, Chinese Academy of Sciences, Kunming (China)

    2014-11-01

    The IceCube (IC) collaboration recently reported the detection of TeV-PeV extraterrestrial neutrinos whose origin is yet unknown. By the photon-neutrino connection in pp and p? interactions, we use the Fermi-LAT observations to constrain the origin of the IC detected neutrinos. We find that Galactic origins, i.e., the diffuse Galactic neutrinos due to cosmic ray (CR) propagation in the Milky Way, and the neutrinos from the Galactic point sources, may not produce the IC neutrino flux, thus these neutrinos should be of extragalactic origin. Moreover, the extragalactic gamma-ray bursts (GRBs) may not account for the IC neutrino flux, the jets of active galactic nuclei may not produce the IC neutrino spectrum, but the starburst galaxies (SBGs) may be promising sources. As suggested by the consistency between the IC detected neutrino flux and the Waxman-Bahcall bound, GRBs in SBGs may be the sources of both the ultrahigh energy, ?> 10{sup 19}eV, CRs and the 1–100 PeV CRs that produce the IC detected TeV-PeV neutrinos.

  20. THE FERMI GBM GAMMA-RAY BURST SPECTRAL CATALOG: FOUR YEARS OF DATA

    SciTech Connect (OSTI)

    Gruber, David; Von Ahlefeld, Victoria Weller; Diehl, Roland; Greiner, Jochen; Von Kienlin, Andreas [Max-Planck-Institut für extraterrestrische Physik, Giessenbachstrasse 1, D-85748 Garching (Germany); Goldstein, Adam; Bhat, P. Narayana; Briggs, Michael S.; Connaughton, Valerie [University of Alabama in Huntsville, 320 Sparkman Drive, Huntsville, AL 35805 (United States); Bissaldi, Elisabetta [Istituto Nazionale di Fisica Nucleare, Sezione di Trieste, I-34127 Trieste (Italy); Byrne, Dave; Fitzpatrick, Gerard; Foley, Suzanne [School of Physics, University College Dublin, Belfield, Stillorgan Road, Dublin 4 (Ireland); Cleveland, William H. [Universities Space Research Association, 320 Sparkman Drive, Huntsville, AL 35805 (United States); Fishman, Gerald J.; Kouveliotou, Chryssa [Space Science Office, VP62, NASA/Marshall Space Flight Center, Huntsville, AL 35812 (United States); Gibby, Melissa; Giles, Misty M. [Jacobs Technology, Inc., Huntsville, AL (United States); Guiriec, Sylvain [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Van der Horst, Alexander J. [Astronomical Institute, University of Amsterdam, Science Park 904, 1098 XH Amsterdam (Netherlands); and others

    2014-03-01

    In this catalog we present the updated set of spectral analyses of gamma-ray bursts (GRBs) detected by the Fermi Gamma-Ray Burst Monitor during its first four years of operation. It contains two types of spectra, time-integrated spectral fits and spectral fits at the brightest time bin, from 943 triggered GRBs. Four different spectral models were fitted to the data, resulting in a compendium of more than 7500 spectra. The analysis was performed similarly but not identically to Goldstein et al. All 487 GRBs from the first two years have been re-fitted using the same methodology as that of the 456 GRBs in years three and four. We describe, in detail, our procedure and criteria for the analysis and present the results in the form of parameter distributions both for the observer-frame and rest-frame quantities. The data files containing the complete results are available from the High-Energy Astrophysics Science Archive Research Center.

  1. Extended Theory of Finite Fermi Systems (Collective Vibrations in Closed Shell Nuclei)

    E-Print Network [OSTI]

    S. Kamerdzhiev; J. Speth; G. Tertychny

    2003-11-18

    We review an extension of Migdal's Theory of Finite Fermi Systems which has been developed and applied to collective vibrations in closed shell nuclei in the past ten years. This microscopic approach is based on a consistent use of the Green function method. Here one considers in a consistent way more complex 1p1h$\\otimes$phonon configurations beyond the RPA correlations. Moreover, these configurations are not only included in the excited states but also explicitly in the ground states of nuclei. The method has been applied to the calculation of the strength distribution and transition densities of giant electric and magnetic resonances in stable and unstable magic nuclei. Using these microscopic transition densities, cross sections for inelastic electron and alpha scattering have been calculated and compared with the available experimental data. The method also allows one to extract in a consistent way the magnitude of the strength of the various multipoles in the energy regions in which several multipoles overlap. We compare the microscopic transition densities, the strength distributions and the various multipole strengths with their values extracted phenomenologically.

  2. Fermi Large Area Telescope Observations of the Cygnus Loop Supernova Remnant

    SciTech Connect (OSTI)

    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.

    2011-11-08

    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.

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

    SciTech Connect (OSTI)

    Abedinpour, Saeed H.; Asgari, Reza; Tanatar, B.; Polini, Marco

    2014-01-15

    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.

  4. Viscosity and scale invariance in the unitary Fermi gas

    E-Print Network [OSTI]

    Tilman Enss; Rudolf Haussmann; Wilhelm Zwerger

    2010-10-12

    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.

  5. Towards a Supersymmetric Description of the Fermi Galactic Center Excess

    E-Print Network [OSTI]

    Matthew Cahill-Rowley; Jamie Gainer; JoAnne Hewett; Tom Rizzo

    2015-03-04

    We attempt to build a model that describes the {\\it Fermi} galactic gamma-ray excess (FGCE) within a UV-complete Supersymmetric framework; we find this to be highly non-trivial. At the very least a successful Supersymmetric explanation must have several important ingredients in order to fit the data and satisfy other theoretical and experimental constraints. Under the assumption that a {\\it single} annihilation mediator is responsible for both the observed relic density as well as the FGCE, we show that the requirements are not easily satisfied in many TeV-scale SUSY models, but can be met with some model building effort in the general NMSSM with $\\sim 10$ parameters beyond the MSSM. We find that the data selects a particular region of the parameter space with a mostly singlino lightest Supersymmetric particle and a relatively light CP-odd Higgs boson that acts as the mediator for dark matter annihilation. We study the predictions for various observables within this parameter space, and find that searches for this light CP-odd state at the LHC, as well as searches for the direct detection of dark matter, are likely to be quite challenging. It is possible that a signature could be observed in the flavor sector; however, indirect detection remains the best probe of this scenario.

  6. Toward a sub-ppm measurement of the Fermi constant

    E-Print Network [OSTI]

    David M. Webber

    2010-06-21

    The Fermi constant, G_F, describes the strength of the weak force and is determined most precisely from the mean life of the positive muon, tau_mu. Advances in theory have reduced the theoretical uncertainty on G_F as calculated from tau_mu to a few tenths of a part per million (ppm). The remaining uncertainty on G_F is entirely experimental, and is dominated by the uncertainty on tau_mu. The MuLan experiment is designed to measure the muon lifetime to part-per-million precision, a better-than twenty-fold improvement over the previous generation of experiments. In 2007, we reported an intermediate result, tau_mu=2.197013(24) microseconds (11 ppm), which is in excellent agreement with the previous world average. This mean life was measured using a pulsed surface muon beam stopped in a ferromagnetic target, surrounded by a symmetric scintillator detector array. Since this intermediate measurement, the detector was instrumented with waveform digitizers, the muon beam rate and beam extinction were increased, and two data sets were acquired on different targets, each containing over 10^12 muon decays. These data will lead to a new determination of G_F to better than a part per million.

  7. Fermi 2: Independent safety assessment of refueling outage

    SciTech Connect (OSTI)

    Arora, H.O. [Detroit Edison, MI (United States)

    1994-12-31

    Industry experience and studies conducted by the U.S. Nuclear Regulatory Commission (NRC) have shown that plants are susceptible to a variety of events that can challenge safety during shutdowns. While these events have neither posed nor indicated an undue risk to public health and safety, they do serve to underscore the importance of effective outage planning and control. The NUMARC 91-06 guidelines suggest that proper planning and execution of outage activities can reduce the likelihood and consequences of events, which ultimately enhances safety during shutdown. The Fermi 2, Independent Safety Engineering Group (ISEG) is charged with the independent safety review of the refueling outage plan and its implementation. The ISEG is responsible for performing a detailed and critical review of proposed outage plan prior to the start of the outage, maintaining surveillance of the adequacy and consistency of the {open_quotes}defense-in-depth{close_quotes} provided during the outage, reviewing the outage plan changes for potential vulnerabilities that could affect safety functions, and investigating selected events that emerge during the course of the outage.

  8. Analysis of Fermi Gamma-Ray Burst duration distribution

    E-Print Network [OSTI]

    Tarnopolski, Mariusz

    2015-01-01

    Two classes of GRBs, short and long, have been determined without any doubts, and are usually prescribed to different physical scenarios. A third class, intermediate in $T_{90}$ durations, has been reported to be present in the datasets of BATSE, Swift, RHESSI and possibly BeppoSAX. The latest release of $>1500$ GRBs observed by Fermi gives an opportunity to further investigate the duration distribution. The aim of this paper is to investigate whether a third class is present in the $\\log T_{90}$ distribution, or is it described by a bimodal distribution. A standard $\\chi^2$ fitting of a mixture of Gaussians is applied to 25 histograms with different binnings. Different binnings give various values of the fitting parameters, as well as the shape of the fitted curve. Among five statistically significant fits none is trimodal. Locations of the Gaussian components are in agreement with previous works. However, a trimodal distribution, understood in the sense of having three separated peaks, is not found for any ...

  9. Experiences with string matching on the Fermi Architecture

    SciTech Connect (OSTI)

    Tumeo, Antonino; Secchi, Simone; Villa, Oreste

    2011-02-25

    String matching is at the core of many real-world applications, such as security, bioinformatic, data mining. All these applications requires the ability to match always growing data sets against large dictionaries effectively, fastly and possibly in real time. Unfortunately, string matching is a computationally intensive procedure which poses significant challenges on current software and hardware implementations. Graphic Processing Units (GPU) have become an interesting target for such high-throughput applications, but the algorithms and the data structures need to be redesigned to be parallelized and adapted to the underlining hardware, coping with the limitations imposed by these architectures. In this paper we present an efficient implementation of the Aho-Corasick string matching algorithm on GPU, showing how we progressively redesigned the algorithm and the data structures to fit on the architecture. We then evaluate the implementation on single and multiple Tesla C2050 (T20 ``Fermi'' based) boards, comparing them to the previous Tesla C1060 (T10 based) solutions and equivalent multicore implementations on x86 CPUs. We discuss the various tradeoffs of the different architectures.

  10. Towards a supersymmetric description of the Fermi Galactic center excess

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

    Cahill-Rowley, M.; Gainer, J. S.; Hewett, J. L.; Rizzo, T. G.

    2015-02-10

    We attempt to build a model that describes the Fermi galactic gamma-ray excess (FGCE) within a UV-complete Supersymmetric framework; we find this to be highly non-trivial. At the very least a successful Supersymmetric explanation must have several important ingredients in order to fit the data and satisfy other theoretical and experimental constraints. Under the assumption that a single annihilation mediator is responsible for both the observed relic density as well as the FGCE, we show that the requirements are not easily satisfied in many TeV-scale SUSY models, but can be met with some model building effort in the general NMSSMmore »with ~ 10 parameters beyond the MSSM. We find that the data selects a particular region of the parameter space with a mostly singlino lightest Supersymmetric particle and a relatively light CP-odd Higgs boson that acts as the mediator for dark matter annihilation. We study the predictions for various observables within this parameter space, and find that searches for this light CP-odd state at the LHC, as well as searches for the direct detection of dark matter, are likely to be quite challenging. It is possible that a signature could be observed in the flavor sector; however, indirect detection remains the best probe of this scenario.« less

  11. Relativistic Fermi-Ulam map: Application to WEGA stellarator lower hybrid power operation

    SciTech Connect (OSTI)

    Fuchs, V.; Seidl, J.; Krlín, L.; Pánek, R.; Preinhaelter, J.; Urban, J.; Laqua, H. P.

    2014-06-15

    Analytical and numerical support is here provided in support of the explanation [Laqua et al., Plasma Phys. Controlled Fusion 56, 075022 (2014)] for the observation of ?MeV electrons during Lower Hybrid (LH) operation in EC pre-heated plasma at the WEGA stellarator [Otte et al., Nukleonika, 57, 171 (2012)]. In the quoted experiments, LH power from the WEGA TE{sub 11} circular waveguide, 9?cm diameter, un-phased, 2.45?GHz antenna, is radiated into a B???0.5?T, n{sup ¯}{sub e}???5?×?10{sup 17} 1/m{sup 3} plasma at T{sub e}???10?eV bulk temperature with an EC-generated 50?keV population of electrons. In response, the fast electrons travel around flux or drift surfaces essentially without collisions, repeatedly interacting with the rf field close to the antenna mouth, and gaining energy in the process. Our WEGA antenna calculations indicate a predominantly standing electric field pattern at the antenna mouth. From a simple approximation of the corresponding Hamiltonian equations of motion, we derive here a relativistic generalization of the simplified area-preserving Fermi-Ulam (F-U) map [M. A. Lieberman and A. J. Lichtenberg, Phys. Rev. A 5, 1852 (1972), Lichtenberg et al., Physica D 1, 291 (1980)], allowing phase-space global stochasticity analysis. At typical WEGA plasma and antenna conditions, and with correlated phases between electron–antenna electric field interaction events, the F-U map and supporting numerical simulations predict an absolute energy barrier in the range of 300?keV. In contrast, with random phases intervening between interaction events, the electron energy can reach ?MeV values, compatible with the measurements on WEGA [Laqua et al., Plasma Phys. Controlled Fusion 56, 075022 (2014)].

  12. CO M PUTATIO NAL M ETHO D S F O R M ESO SCO PIC, INHO M O G ENEO US PLASTIC D EF O R M ATIO N

    E-Print Network [OSTI]

    Ghoniem, Nasr M.

    CO M PUTATIO NAL M ETHO D S F O R M ESO SCO PIC, INHO M O G ENEO US PLASTIC D EF O R M ATIO N Nasr of heterogeneuos plastic deformation in materials. The equations of motion of three-dimensional (3-D) inter- acting simulations of inhomogeneous plastic deformation, and associated applications in pattern-forming plastic

  13. SPA will continue to process proposals during the cut over period and will collect required information from the PRF and proposal that will then be entered into EFS (PS 9.2) once the upgrade has been successfully

    E-Print Network [OSTI]

    Thomas, David D.

    GMUN/CA's, Proposals: SPA will continue to process proposals during the cut over period: To allow enough time for SPA to review/process PO's and sub invoices (that have been approved by PI on Monday, 3/30 processing prior to the EFS cutover. 2. Domestic sub invoices need to be received by SPA

  14. Measurement of the Positive Muon Lifetime and Determination of the Fermi Constant to Part-per-Million Precision

    E-Print Network [OSTI]

    D. M. Webber; V. Tishchenko; Q. ~Peng; S. Battu; R. M. Carey; D. B. Chitwood; J. Crnkovic; P. T. Debevec; S. Dhamija; W. Earle; A. Gafarov; K. Giovanetti; T. P. Gorringe; F. E. Gray; Z. Hartwig; D. W. Hertzog; B. Johnson; P. Kammel; B. Kiburg; S. Kizilgul; J. Kunkle; B. Lauss; I. Logashenko; K. R. Lynch; R. McNabb; J. P. Miller; F. Mulhauser; C. J. G. Onderwater; J. Phillips; S. Rath; B. L. Roberts; P. Winter; B. Wolfe

    2010-12-06

    We report a measurement of the positive muon lifetime to a precision of 1.0 parts per million (ppm); it is the most precise particle lifetime ever measured. The experiment used a time-structured, low-energy muon beam and a segmented plastic scintillator array to record more than 2 x 10^{12} decays. Two different stopping target configurations were employed in independent data-taking periods. The combined results give tau_{mu^+}(MuLan) = 2196980.3(2.2) ps, more than 15 times as precise as any previous experiment. The muon lifetime gives the most precise value for the Fermi constant: G_F(MuLan) = 1.1663788 (7) x 10^-5 GeV^-2 (0.6 ppm). It is also used to extract the mu^-p singlet capture rate, which determines the proton's weak induced pseudoscalar coupling g_P.

  15. Quantum Monte Carlo Study of the Ground-State Properties of a Fermi Gas in the BCS-BEC Crossover

    SciTech Connect (OSTI)

    Giorgini, S.; Astrakharchik, G. E.; Boronat, J.; Casulleras, J.

    2006-11-07

    The ground-state properties of a two-component Fermi gas with attractive short-range interactions are calculated using the fixed-node diffusion Monte Carlo method. The interaction strength is varied over a wide range by tuning the value of the s-wave scattering length of the two-body potential. We calculate the ground-state energy per particle and we characterize the equation of state of the system. Off-diagonal long-range order is investigated through the asymptotic behavior of the two-body density matrix. The condensate fraction of pairs is calculated in the unitary limit and on both sides of the BCS-BEC crossover.

  16. Brightest Fermi-LAT flares of PKS 1222+216: implications on emission and acceleration processes

    SciTech Connect (OSTI)

    Kushwaha, Pankaj; Singh, K. P.; Sahayanathan, Sunder

    2014-11-20

    We present a high time resolution study of the two brightest ?-ray outbursts from a blazar PKS 1222+216 observed by the Fermi Large Area Telescope (LAT) in 2010. The ?-ray light curves obtained in four different energy bands, 0.1-3, 0.1-0.3, 0.3-1, and 1-3 GeV, with time bins of six hours, show asymmetric profiles with similar rise times in all the bands but a rapid decline during the April flare and a gradual one during the June flare. The light curves during the April flare show an ?2 day long plateau in 0.1-0.3 GeV emission, erratic variations in 0.3-1 GeV emission, and a daily recurring feature in 1-3 GeV emission until the rapid rise and decline within a day. The June flare shows a monotonic rise until the peak, followed by a gradual decline powered mainly by the multi-peak 0.1-0.3 GeV emission. The peak fluxes during both the flares are similar except in the 1-3 GeV band in April, which is twice the corresponding flux during the June flare. Hardness ratios during the April flare indicate spectral hardening in the rising phase followed by softening during the decay. We attribute this behavior to the development of a shock associated with an increase in acceleration efficiency followed by its decay leading to spectral softening. The June flare suggests hardening during the rise followed by a complicated energy dependent behavior during the decay. Observed features during the June flare favor multiple emission regions while the overall flaring episode can be related to jet dynamics.

  17. Two Emission Mechanisms in the Fermi Bubbles: A Possible Signal of Annihilating Dark Matter

    SciTech Connect (OSTI)

    Hooper, Dan; Slatyer, Tracy R.

    2013-09-01

    We study the variation of the spectrum of the Fermi Bubbles with Galactic latitude. Far from the Galactic plane (|b| > 30 degrees), the observed gamma-ray emission is nearly invariant with latitude, and is consistent with arising from inverse Compton scattering of the interstellar radiation field by cosmic-ray electrons with an approximately power-law spectrum. The same electrons in the presence of microgauss-scale magnetic fields can also generate the the observed microwave "haze". At lower latitudes (b < 20 degrees), in contrast, the spectrum of the emission correlated with the Bubbles possesses a pronounced spectral feature peaking at 1-4 GeV (in E^2 dN/dE) which cannot be generated by any realistic spectrum of electrons. Instead, we conclude that a second (non-inverse-Compton) emission mechanism must be responsible for the bulk of the low-energy, low-latitude emission. This second component is spectrally similar to the excess GeV emission previously reported from the Galactic Center (GC), and also appears spatially consistent with a luminosity per volume falling approximately as r^-2.4, where r is the distance from the GC. We argue that the spectral feature visible in the low-latitude Bubbles is the extended counterpart of the GC excess, now detected out to at least 2-3 kpc from the GC. The spectrum and angular distribution of the signal is consistent with that predicted from ~10 GeV dark matter particles annihilating to leptons, or from ~50 GeV dark matter particles annihilating to quarks, following a distribution similar to the canonical Navarro-Frenk-White (NFW) profile. We also consider millisecond pulsars as a possible astrophysical explanation for the signal, as observed millisecond pulsars possess a spectral cutoff at approximately the required energy. Any such scenario would require a large population of unresolved millisecond pulsars extending at least 2-3 kpc from the GC.

  18. Revised FINAL–REPORT NO. 2: INDEPENDENT CONFIRMATORY SURVEY SUMMARY AND RESULTS FOR THE ENRICO FERMI ATOMIC POWER PLANT, UNIT 1, NEWPORT, MICHIGAN (DOCKET NO. 50 16; RFTA 10-004) 2018-SR-02-1

    SciTech Connect (OSTI)

    Erika Bailey

    2011-10-27

    The Enrico Fermi Atomic Power Plant, Unit 1 (Fermi 1) was a fast breeder reactor design that was cooled by sodium and operated at essentially atmospheric pressure. On May 10, 1963, the Atomic Energy Commission (AEC) granted an operating license, DPR-9, to the Power Reactor Development Company (PRDC), a consortium specifically formed to own and operate a nuclear reactor at the Fermi 1 site. The reactor was designed for a maximum capability of 430 megawatts (MW); however, the maximum reactor power with the first core loading (Core A) was 200 MW. The primary system was filled with sodium in December 1960 and criticality was achieved in August 1963. The reactor was tested at low power during the first couple years of operation. Power ascension testing above 1 MW commenced in December 1965 immediately following the receipt of a high-power operating license. In October 1966 during power ascension, zirconium plates at the bottom of the reactor vessel became loose and blocked sodium coolant flow to some fuel subassemblies. Two subassemblies started to melt and the reactor was manually shut down. No abnormal releases to the environment occurred. Forty-two months later after the cause had been determined, cleanup completed, and the fuel replaced, Fermi 1 was restarted. However, in November 1972, PRDC made the decision to decommission Fermi 1 as the core was approaching its burn-up limit. The fuel and blanket subassemblies were shipped off-site in 1973. Following that, the secondary sodium system was drained and sent off-site. The radioactive primary sodium was stored on-site in storage tanks and 55 gallon (gal) drums until it was shipped off-site in 1984. The initial decommissioning of Fermi 1 was completed in 1975. Effective January 23, 1976, DPR-9 was transferred to the Detroit Edison Company (DTE) as a 'possession only' license (DTE 2010a). This report details the confirmatory activities performed during the second Oak Ridge Institute for Science and Education (ORISE) site visit to Fermi 1 in November 2010. The survey was strategically planned during a Unit 2 (Fermi 2) outage to take advantage of decreased radiation levels that were observed and attributed to Fermi 2 from the operating unit during the first site visit. However, during the second visit there were elevated radiation levels observed and attributed to the partially dismantled Fermi 1 reactor vessel and a waste storage box located on the 3rd floor of the Fermi 1 Turbine Building. Confirmatory surveys (unshielded) performed directly in the line of sight of these areas were affected. The objective of the confirmatory survey was to verify that the final radiological conditions were accurately and adequately described in Final Status Survey (FSS) documentation, relative to the established release criteria. This objective was achieved by performing document reviews, as well as independent measurements and sampling. Specifically, documentation of the planning, implementation, and results of the FSS were evaluated; side-by-side FSS measurement and source comparisons were performed; site areas were evaluated relative to appropriate FSS classification; and areas were assessed for residual, undocumented contamination.

  19. Measurement of the Cosmic Ray e+ plus e- spectrum from 20 GeV to 1 TeV with the Fermi Large Area Telescope

    E-Print Network [OSTI]

    Fermi/LAT Collaboration

    2009-04-30

    Designed as a high-sensitivity gamma-ray observatory, the Fermi Large Area Telescope is also an electron detector with a large acceptance exceeding 2m^2 sr at 300 GeV. Building on the gamma-ray analysis, we have developed an efficient electron detection strategy which provides sufficient background rejection for measurement of the steeply-falling electron spectrum up to 1 TeV. Our high precision data show that the electron spectrum falls with energy as E^(-3.0) and does not exhibit prominent spectral features. Interpretations in terms of a conventional diffusive model as well as a potential local extra component are briefly discussed.

  20. Closure & Waste Management Environmental Impact Statement (EfS)

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 OutreachProductswsicloudwsiclouddenDVA N C E D BGene NetworkNuclearDNP 20082 P r o j e

  1. Hunting for treasures among the Fermi unassociated sources: A multiwavelength approach

    SciTech Connect (OSTI)

    Acero, F.; Ojha, R.; Edwards, P. G.; Blanchard, J.; Lovell, J. E. J.; Thompson, D. J.

    2013-12-20

    The Fermi Gamma-Ray Space Telescope has been detecting a wealth of sources where the multiwavelength counterpart is either inconclusive or missing altogether. We present a combination of factors that can be used to identify multiwavelength counterparts to these Fermi unassociated sources. This approach was used to select and investigate seven bright, high-latitude unassociated sources with radio, UV, X-ray, and ?-ray observations. As a result, four of these sources are candidates to be active galactic nuclei, and one to be a pulsar, while two do not fit easily into these known categories of sources. The latter pair of extraordinary sources might reveal a new category subclass or a new type of ?-ray emitter. These results altogether demonstrate the power of a multiwavelength approach to illuminate the nature of unassociated Fermi sources.

  2. 4.5 years multi-wavelength observations of Mrk 421 during the ARGO-YBJ and Fermi common operation time

    E-Print Network [OSTI]

    Bartoli, B; Bi, X J; Cao, Z; Catalanotti, S; Chen, S Z; Chen, T L; Cui, S W; Dai, B Z; Damone, A; Danzengluobu,; De Mitri, I; Piazzoli, B D Ettorre; Di Girolamo, T; Di Sciascio, G; Feng, C F; Feng, Zhaoyang; Feng, Zhenyong; Gou, Q B; Guo, Y Q; He, H H; Hu, Haibing; Hu, Hongbo; Iacovacci, M; Iuppa, R; Jia, H Y; Labaciren,; Li, H J; Liu, C; Liu, J; Liu, M Y; Lu, H; Ma, L L; Ma, X H; Mancarella, G; Mari, S M; Marsella, G; Mastroianni, S; Montini, P; Ning, C C; Perrone, L; Pistilli, P; Salvini, P; Santonico, R; Shen, P R; Sheng, X D; Shi, F; Surdo, A; Tan, Y H; Vallania, P; Vernetto, S; Vigorito, C; Wang, H; Wu, C Y; Wu, H R; Xue, L; Yang, Q Y; Yang, X C; Yao, Z G; Yuan, A F; Zha, M; Zhang, H M; Zhang, L; Zhang, X Y; Zhang, Y; Zhao, J; Zhaxiciren,; Zhaxisangzhu,; Zhou, X X; Zhu, F R; Zhu, Q Q

    2015-01-01

    We report on the extensive multi-wavelength observations of the blazar Markarian 421 (Mrk 421) covering radio to gamma-rays, during the 4.5 year period of ARGO-YBJ and Fermi common operation time, from August 2008 to February 2013. In particular, thanks to the ARGO-YBJ and Fermi data, the whole energy range from 100 MeV to 10 TeV is covered without any gap. In the observation period, Mrk 421 showed both low and high activity states at all wavebands. The correlations among flux variations in different wavebands were analyzed. Seven large flares, including five X-ray flares and two GeV gamma-ray flares with variable durations (3-58 days), and one X-ray outburst phase were identified and used to investigate the variation of the spectral energy distribution with respect to a relative quiescent phase. During the outburst phase and the seven flaring episodes, the peak energy in X-rays is observed to increase from sub-keV to few keV. The TeV gamma-ray flux increases up to 0.9-7.2 times the flux of the Crab Nebula. T...

  3. A new part-per-million measurement of the positive muon lifetime and determination of the Fermi Constant

    E-Print Network [OSTI]

    David M. Webber

    2011-09-29

    The Fermi Constant, G_F, describes the strength of the weak force and is determined most precisely from the mean life of the positive muon, tau_mu. Advances in theory have reduced the theoretical uncertainty on G_F as calculated from tau_mu to a few tenths of a part per million (ppm). Until recently, the remaining uncertainty on G_F was entirely experimental and dominated by the uncertainty on tau_mu. We report the MuLan collaboration's recent 1.0 ppm measurement of the positive muon lifetime. This measurement is over a factor of 15 more precise than any previous measurement, and is the most precise particle lifetime ever measured. The experiment used a time-structured low-energy muon beam and an array of plastic scintillators read-out by waveform digitizers and a fast data acquisition system to record over 2 times 10^{12} muon decays. Two different in-vacuum muon-stopping targets were used in separate data-taking periods. The results from these two data-taking periods are in excellent agreement. The combined results give tau_{mu^+}({MuLan})=2196980.3(2.2) ps. This measurement of the muon lifetime gives the most precise value for the Fermi Constant: G_F({MuLan}) = 1.1663788 (7) \\times 10^{-5} {GeV}^{-2} (0.6 ppm). The lifetime is also used to extract the mu^-p singlet capture rate, which determines the proton's weak induced pseudoscalar coupling g_P.

  4. PROBING MILLISECOND PULSAR EMISSION GEOMETRY USING LIGHT CURVES FROM THE FERMI/LARGE AREA TELESCOPE

    SciTech Connect (OSTI)

    Venter, C.; Harding, A. K. [Astrophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Guillemot, L. [Universite de Bordeaux, Centre d'Etudes Nucleaires Bordeaux Gradignan, UMR 5797, Gradignan, 33175 (France)

    2009-12-10

    An interesting new high-energy pulsar sub-population is emerging following early discoveries of gamma-ray millisecond pulsars (MSPs) by the Fermi Large Area Telescope (LAT). We present results from three-dimensional emission modeling, including the special relativistic effects of aberration and time-of-flight delays and also rotational sweepback of B-field lines, in the geometric context of polar cap (PC), outer gap (OG), and two-pole caustic (TPC) pulsar models. In contrast to the general belief that these very old, rapidly rotating neutron stars (NSs) should have largely pair-starved magnetospheres due to the absence of significant pair production, we find that most of the light curves are best fit by TPC and OG models, which indicates the presence of narrow accelerating gaps limited by robust pair production-even in these pulsars with very low spin-down luminosities. The gamma-ray pulse shapes and relative phase lags with respect to the radio pulses point to high-altitude emission being dominant for all geometries. We also find exclusive differentiation of the current gamma-ray MSP population into two MSP sub-classes: light curve shapes and lags across wavebands impose either pair-starved PC (PSPC) or TPC/OG-type geometries. In the first case, the radio pulse has a small lag with respect to the single gamma-ray pulse, while the (first) gamma-ray peak usually trails the radio by a large phase offset in the latter case. Finally, we find that the flux correction factor as a function of magnetic inclination and observer angles is typically of order unity for all models. Our calculation of light curves and flux correction factor for the case of MSPs is therefore complementary to the 'ATLAS paper' of Watters et al. for younger pulsars.

  5. Distribution of occupation numbers in finite Fermi systems and role of interaction in chaos and thermalization

    SciTech Connect (OSTI)

    Flambaum, V.V.; Izrailev, F.M. [School of Physics, University of New South Wales, Sydney 2052 (Australia)] [School of Physics, University of New South Wales, Sydney 2052 (Australia)

    1997-01-01

    A method is developed for calculation of single-particle occupation numbers in finite Fermi systems of interacting particles. It is more accurate than the canonical distribution method and gives the Fermi-Dirac distribution in the limit of large number of particles. It is shown that statistical effects of the interaction are absorbed by an increase of the effective temperature. Criteria for quantum chaos and statistical equilibrium are considered. All results are confirmed by numerical experiments in the two-body random interaction model. {copyright} {ital 1997} {ital The American Physical Society}

  6. Natural orbits of atomic Cooper pairs in a nonuniform Fermi gas

    E-Print Network [OSTI]

    Y. H. Pong; C. K. Law

    2006-05-08

    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.

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

    Office of Science (SC) Website

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power AdministrationRobust,Field-effectWorkingLosThe 26thI D- 6 0GrantsThe Life of Enrico Fermi The Enrico Fermi

  8. Fermi National Accelerator Laboratory | U.S. DOE Office of Science (SC)

    Office of Science (SC) Website

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power AdministrationRobust,Field-effectWorkingLosThe 26thIWalter H. Zinn,Christopher Charges/Reports7FermiFermi

  9. Fermi National Accelerator Laboratory | U.S. DOE Office of Science (SC)

    Office of Science (SC) Website

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power AdministrationRobust,Field-effectWorkingLosThe 26thIWalterOptimizing(SC) ElectronAugustFebruaryFermiFermi

  10. Fermi National Accelerator Laboratory | U.S. DOE Office of Science (SC)

    Office of Science (SC) Website

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power AdministrationRobust,Field-effectWorkingLosThe 26thIWalterOptimizing(SC)Fermi National AcceleratorFermi

  11. Fermi National Accelerator Laboratory | U.S. DOE Office of Science (SC)

    Office of Science (SC) Website

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power AdministrationRobust,Field-effectWorkingLosThe 26thIWalterOptimizing(SC)Fermi NationalFermi National

  12. EFS Exhibit A General Conditions

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

    Recovery Act (RCRA), and shall apply to any clean-up or response costs occasioned by the transport, treatment, storage or disposal by SUBCONTRACTOR or any third party of...

  13. Simulation of NMR Fermi contact shifts for Lithium battery materials: the need of an efficient hybrid functional approach

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    1 Simulation of NMR Fermi contact shifts for Lithium battery materials: the need of an efficient shift calculations for assisting structural characterization of battery materials, we propose to use them at no additional computational cost. In this paper, NMR Fermi contact shifts for lithium

  14. Zeeman tomography of magnetic white dwarfs IV. The complex field structure of the polars EF Eri, BL Hyi, and CP Tuc

    E-Print Network [OSTI]

    K. Beuermann; F. Euchner; K. Reinsch; S. Jordan; B. T. Gaensicke

    2006-10-26

    The magnetic fields of the accreting white dwarfs (WDs) in magnetic cataclysmic variables (mCVs) determine the accretion geometries, the emission properties, and the secular evolution of these objects. We determine the structure of the surface magnetic fields of the WDs primaries in magnetic CVs using Zeeman tomography. Our study is based on orbital-phase resolved optical flux and circular polarization spectra of the polars EF Eri, BL Hyi, and CP Tuc obtained with FORS1 at the ESO VLT. An evolutionary algorithm is used to synthesize best fits to these spectra from an extensive database of pre-computed Zeeman spectra. The general approach has been described in previous papers of this series. The results achieved with simple geometries as centered or offset dipoles are not satisfactory. Significantly improved fits are obtained for multipole expansions that are truncated at degree l(max)=3 or 5 and include all tesseral and sectoral components with 0CP Tuc and the ranges of field strength covered are similar for the dipole and multipole models, but only the latter provide access to accreting matter at the right locations on the WD. The results suggest that the field geometries of the WDs in short-period mCVs are quite complex with strong contributions from multipoles higher than the dipole in spite of a typical age of the WDs in CVs in excess of 1 Gyr. It is feasible to derive the surface field structure of an accreting WD from phase-resolved low-state circular spectropolarimetry of sufficiently high signal-to-noise ratio. The fact that independent information is available on the strength and direction of the field in the accretion spot from high-state observations helps in unraveling the global field structure.

  15. Enrico Fermi's Impact on Science - John Marburger Speech

    Office of Scientific and Technical Information (OSTI)

    energy. This was the beginning of nuclear spectroscopy, an essential tool for the production and application of isotopes in chemistry, medicine, and materials science - a field...

  16. RAPID COMMUNICATIONS PHYSICAL REVIEW B 84, 180511(R) (2011)

    E-Print Network [OSTI]

    Johnson, Peter D.

    2011-01-01

    -dependent single-particle scattering rates of car- riers at T Tc, at the Fermi energy EF on the Fermi surface (FS, and energy for cuprate superconductors based on photoemission measurements of Bi2Sr2CaCu2O8+ J. D. Rameau, Z.-H. Pan, H.-B. Yang, G. D. Gu, and P. D. Johnson Brookhaven National Laboratory, Upton, New York 11973

  17. Data:0c7149ef-adf6-42a7-963d-4b12a98d024d | Open Energy Information

    Open Energy Info (EERE)

    adf6-42a7-963d-4b12a98d024d No revision has been approved for this page. It is currently under review by our subject matter experts. Jump to: navigation, search Loading... 1. Basic...

  18. Data:160c06ef-99c8-45a6-9685-727a8ae18799 | Open Energy Information

    Open Energy Info (EERE)

    a8ae18799 No revision has been approved for this page. It is currently under review by our subject matter experts. Jump to: navigation, search Loading... 1. Basic Information 2....

  19. Published: March 08, 2011 r 2011 American Chemical Society 1597 dx.doi.org/10.1021/ef101522w |Energy Fuels 2011, 25, 15971604

    E-Print Network [OSTI]

    Zare, Richard N.

    desorption by irradiation with the 10.6 m output of a CO2 laser followed by single-photon ionization is island-like. ' INTRODUCTION Asphaltenes compose a fraction of petroleum defined by their insolubility in n-pentane or n-heptane and solubility in benzene or toluene. This fraction is a very complex mixture

  20. Published: October 21, 2011 r 2011 American Chemical Society 5493 dx.doi.org/10.1021/ef201329x |Energy Fuels 2011, 25, 54935502

    E-Print Network [OSTI]

    Azad, Abdul-Majeed

    . Among these, carbon capture and storage (CCS) is considered promising. The chemical-looping combustion separation of carbon dioxide. In this work, the feasibility of CuO supported on Al2O3 and MgAl2O4 for CLC of alternative technologies have been proposed to mitigate the rising levels of carbon dioxide in the atmosphere

  1. Inferred cosmic-ray spectrum from ${\\it Fermi}$-LAT $\\gamma$-ray observations of the Earth's limb

    E-Print Network [OSTI]

    :,; Ajello, M; Albert, A; Allafort, A; Baldini, L; Barbiellini, G; Bastieri, D; Bechtol, K; Bellazzini, R; Blandford, R D; Bloom, E D; Bonamente, E; Bottacini, E; Bouvier, A; Brandt, T J; Brigida, M; Bruel, P; Buehler, R; Buson, S; Caliandro, G A; Cameron, R A; Caraveo, P A; Cecchi, C; Charles, E; Chaves, R C G; Chekhtman, A; Chiang, J; Chiaro, G; Ciprini, S; Claus, R; Cohen-Tanugi, J; Conrad, J; Cutini, S; Dalton, M; D'Ammando, F; de Angelis, A; de Palma, F; Dermer, C D; Digel, S W; Di Venere, L; Silva, E do Couto e; Drell, P S; Drlica-Wagner, A; Favuzzi, C; Fegan, S J; Ferrara, E C; Focke, W B; Franckowiak, A; Fukazawa, Y; Funk, S; Fusco, P; Gargano, F; Gasparrini, D; Germani, S; Giglietto, N; Giordano, F; Giroletti, M; Glanzman, T; Godfrey, G; Gomez-Vargas, G A; Grenier, I A; Grove, J E; Guiriec, S; Gustafsson, M; Hadasch, D; Hanabata, Y; Harding, A K; Hayashida, M; Hayashi, K; Hewitt, J W; Horan, D; Hou, X; Hughes, R E; Inoue, Y; Jackson, M S; Jogler, T; Jóhannesson, G; Johnson, A S; Kamae, T; Kawano, T; Knödlseder, J; Kuss, M; Lande, J; Larsson, S; Latronico, L; Longo, F; Loparco, F; Lovellette, M N; Lubrano, P; Mayer, M; Mazziotta, M N; McEnery, J E; Mehault, J; Michelson, P F; Mitthumsiri, W; Mizuno, T; Moiseev, A A; Monte, C; Monzani, M E; Morselli, A; Moskalenko, I V; Murgia, S; Nemmen, R; Nuss, E; Ohsugi, T; Okumura, A; Orienti, M; Orlando, E; Ormes, J F; Paneque, D; Panetta, J H; Perkins, J S; Pesce-Rollins, M; Piron, F; Pivato, G; Porter, T A; Rainò, S; Rando, R; Razzano, M; Razzaque, S; Reimer, A; Reimer, O; Ritz, S; Roth, M; Schaal, M; Schulz, A; Sgrò, C; Siskind, E J; Spandre, G; Spinelli, P; Strong, A W; Takahashi, H; Takeuchi, Y; 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; Werner, M; Winer, B L; Wood, K S; Wood, M; Yang, Z

    2014-01-01

    Recent accurate measurements of cosmic-ray (CR) species by ATIC-2, CREAM, and PAMELA reveal an unexpected hardening in the proton and He spectra above a few hundred GeV, a gradual softening of the spectra just below a few hundred GeV, and a harder spectrum of He compared to that of protons. These newly-discovered features may offer a clue to the origin of high-energy CRs. We use the ${\\it Fermi}$ Large Area Telescope observations of the $\\gamma$-ray emission from the Earth's limb for an indirect measurement of the local spectrum of CR protons in the energy range $\\sim 90~$GeV-$6~$TeV (derived from a photon energy range $15~$GeV-$1~$TeV). Our analysis shows that single power law and broken power law spectra fit the data equally well and yield a proton spectrum with index $2.68 \\pm 0.04$ and $2.61 \\pm 0.08$ above $\\sim 200~$GeV, respectively.

  2. A Measurement Study of GPU DVFS on Energy Conservation Xinxin Mei, Ling Sing Yung, Kaiyong Zhao, Xiaowen Chu

    E-Print Network [OSTI]

    Chu, Xiaowen

    DVFS is an ef- fective approach to conserving energy. For example, by scaling down the GPU core voltage at full load. How to conserver energy on such GPU platforms becomes an important problem. Dynamic voltageA Measurement Study of GPU DVFS on Energy Conservation Xinxin Mei, Ling Sing Yung, Kaiyong Zhao

  3. Extending the Fermi-LAT Data Processing Pipeline to the Grid

    E-Print Network [OSTI]

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

    2012-12-17

    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)

  4. High-energy cosmic-ray acceleration

    E-Print Network [OSTI]

    Bustamante, M; de Paula, W; Duarte Chavez, J A; Gago, A M; Hakobyan, H; Jez, P; Monroy Montañez, J A; Ortiz Velasquez, A; Padilla Cabal, F; Pino Rozas, M; Rodriguez Patarroyo, D J; Romeo, G L; Saldaña-Salazar , U J; Velasquez, M; von Steinkirch, M

    2010-01-01

    We briefly review the basics of ultrahigh-energy cosmic-ray acceleration. The Hillas criterion is introduced as a geometrical criterion that must be fulfilled by potential acceleration sites, and energy losses are taken into account in order to obtain a more realistic scenario. The different available acceleration mechanisms are presented, with special emphasis on Fermi shock acceleration and its prediction of a power-law cosmic-ray energy spectrum. We conclude that first-order Fermi acceleration, though not entirely satisfactory, is the most promising mechanism for explaining the ultra-high-energy cosmic-ray flux.

  5. Secretary Moniz's Remarks at the 2013 Enrico Fermi Awards Ceremony...

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

    Addthis Dr. Ernest Moniz Dr. Ernest Moniz Secretary of Energy Well, thank you, Pat (Dehmer). It's great to be here for a very, very enjoyable occasion indeed. And actually, with...

  6. Photons from Heavy-Ion Collisions at Fermi Velocity 

    E-Print Network [OSTI]

    Ko, Che Ming; Alchelin, J.

    1987-01-01

    field and the Pauli blocking of nucleon-nucleon collisions has been introduced recently to describe heavy-ion collisions at intermediate energies. ' Important information about the properties of dense nu- clear matter has been extracted by comparing... as a probe of the properties of the dense nu- clear matter, it is necessary to study reactions at higher incident energies where the maximum density reached in the collision is appreciable. One then expects significant eff'ects due to the equation...

  7. Technical Design and Optimization Study for the FERMI@Elettra FELPhotoinjector

    SciTech Connect (OSTI)

    Lidia, Steven M.; Penco, Giuseppe; Trovo', Mauro

    2006-06-30

    The FERMI {at} Elettra FEL project will provide a novel, x-ray free electron laser user facility at Sincrotrone Trieste based on seeded and cascade FEL techniques. The electron beam source and injector systems play a crucial role in the success of the facility by providing the highest quality electron beams to the linac and FEL undulators. This Technical Note examines the critical technology components that make up the injector system, and demonstrates optimum beam dynamics solutions to achieve the required high quality electron beams. Section 2 provides an overview of the various systems and subsystems that comprise the photoinjector. The different operating modes of the injector are described as they pertain to the different linac configurations driven by the FEL and experimental design. For each mode, the required electron beam parameters are given. Sections 3 and 4 describe the critical beamline elements in the injector complex: the photocathode and drive laser, and the RF gun. The required drive laser parameters are given at the end of Section 3. Additional details on the design of the photoinjector drive laser systems are presented in a separate Technical Note. Design considerations for the RF gun are extensively presented in Section 4. There, we describe the variation of the cavity geometry to optimize the efficiency of the energy transfer to the electron beam. A study of the power coupling into the various cavity modes that interact within the bandwidth of the RF drive pulse is presented, followed by a study of the transient cavity response under several models and, finally, the effects on extracted beam quality. Section 5 describes the initial design for the low energy, off-axis diagnostic beamline. Beam dynamics simulations using ASTRA, elegant, and MAD are presented. Section 6 presents the optimization studies for the beam dynamics in the various operating modes. The optimized baseline configurations for the beamline and incident drive laser pulse are presented, supported by simulation results from space-charge tracking codes. Optimization of the beam transport through the downstream linac to the FEL undulator entrance requires significant deviations from the canonical ''flat-top'' temporal laser pulse distribution at the photocathode. The physics of nonlinear electron current emission are examined to determine the optimum temporal profile of the drive laser in order to produce the required linear current ramp at the injector exit. Parametric sensitivity studies are performed around the baseline configurations, and jitter studies are presented that analyze the stability of the solutions.

  8. Correction to kinetic energy density using exactly solvable model

    E-Print Network [OSTI]

    Alexey Sergeev; Raka Jovanovic; Sabre Kais; Fahhad H Alharbi

    2015-06-03

    An accurate non-gradient-expansion based correction to Thomas--Fermi is developed using solvable model. The used model is a system of $N$ non-interacting electrons moving independently in the Coulomb field of the nuclear charge. The presented correction is applicable for atoms and should be extendable beyond that. The method exploits the fact that the difference between the Thomas--Fermi approximation and the non-interacting kinetic energy is comparable to the difference between the same values inside the proposed solvable model. The numerical experiments show that by adding this correction factor, the precision of Thomas--Fermi approximation is enhanced by an order of magnitude.

  9. On the Energy (In)efficiency of Hadoop Clusters Jacob Leverich, Christos Kozyrakis

    E-Print Network [OSTI]

    Kozyrakis, Christos

    resources for large-scale data analysis. However, their ef- fect on datacenter energy efficiency hasOn the Energy (In)efficiency of Hadoop Clusters Jacob Leverich, Christos Kozyrakis Computer Systems Laboratory Stanford University {leverich, kozyraki}@stanford.edu ABSTRACT Distributed processing frameworks

  10. Fermi National Accelerator Laboratory Technologies Available for Licensing

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTechtail.Theory ofDid you not find whatGasEnergy Technologies |FeatureFellows Fellows|- Energy

  11. Observation of an electron band above the Fermi level in FeTe?.??Se?.?? from in-situ surface doping

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

    Zhang, P.; Richard, P.; Xu, N.; Xu, Y. -M.; Ma, J.; Qian, T.; Fedorov, A. V.; Denlinger, J. D.; Gu, G. D.; Ding, H.

    2014-10-27

    We used in-situ potassium (K) evaporation to dope the surface of the iron-based superconductor FeTe?.??Se?.??. The systematic study of the bands near the Fermi level confirms that electrons are doped into the system, allowing us to tune the Fermi level of this material and to access otherwise unoccupied electronic states. In particular, we observe an electron band located above the Fermi level before doping that shares similarities with a small three-dimensional pocket observed in the cousin, heavily-electron-doped KFe??xSe? compound.

  12. Effect of nutrient media on photobiological hydrogen production by Anabaena variabilis ATCC 29413

    E-Print Network [OSTI]

    Berberoglu, Halil; Jay, Jenny; Pilon, Laurent

    2008-01-01

    concentration, (b) light to biomass energy conversion ef?concentration, (b) light to biomass energy conversion ef?measurements, h light to biomass energy conversion ef?

  13. The FermiPastaUlam Problem and the Metastability Perspective

    E-Print Network [OSTI]

    Carati, Andrea

    . First there is a quick formation of a packet of low-frequency modes which do share the energy on the subject, the ones which in our opinion played a significant role with respect to the main question we have was somehow neglected. We will point out later how the relations between the two subjects, solitons and FPU

  14. Topological crystalline insulator Pb{sub x}Sn{sub 1-x}Te thin films on SrTiO{sub 3} (001) with tunable Fermi levels

    SciTech Connect (OSTI)

    Guo, Hua; Liu, Jun-Wei; Wang, Zhen-Yu; Wu, Rui; Ji, Shuai-Hua; Duan, Wen-Hui; Chen, Xi Xue, Qi-Kun; Yan, Chen-Hui; Zhang, Zhi-Dong; Wang, Li-Li; He, Ke; Ma, Xu-Cun

    2014-05-01

    In this letter, we report a systematic study of topological crystalline insulator Pb{sub x}Sn{sub 1-x}Te (0 < x < 1) thin films grown by molecular beam epitaxy on SrTiO{sub 3}(001). Two domains of Pb{sub x}Sn{sub 1-x}Te thin films with intersecting angle of ? ? 45° were confirmed by reflection high energy diffraction, scanning tunneling microscopy, and angle-resolved photoemission spectroscopy (ARPES). ARPES study of Pb{sub x}Sn{sub 1-x}Te thin films demonstrated that the Fermi level of PbTe could be tuned by altering the temperature of substrate whereas SnTe cannot. An M-shaped valance band structure was observed only in SnTe but PbTe is in a topological trivial state with a large gap. In addition, co-evaporation of SnTe and PbTe results in an equivalent variation of Pb concentration as well as the Fermi level of Pb{sub x}Sn{sub 1-x}Te thin films.

  15. Thermoelectric probe for Fermi surface topology in the three-dimensional Rashba semiconductor BiTeI

    E-Print Network [OSTI]

    Ideue, T.

    We have investigated thermoelectric properties of a three-dimensional Rashba system BiTeI. Magnetic-field dependences of the Seebeck effect and Nernst effect show qualitative changes with the Fermi level passing through ...

  16. Role of fourth-order phase-space moments in collective modes of trapped Fermi gases

    SciTech Connect (OSTI)

    Chiacchiera, Silvia; Lepers, Thomas; Davesne, Dany; Urban, Michael

    2011-10-15

    We study the transition from hydrodynamic to collisionless behavior in collective modes of ultracold trapped Fermi gases. To that end, we solve the Boltzmann equation for the trapped Fermi gas via the moments method. We showed previously that it is necessary to go beyond second-order moments if one wants to reproduce the results of a numerical solution of the Boltzmann equation. Here, we will give the detailed description of the method including fourth-order moments. We apply this method to the case of realistic parameters, and compare the results for the radial quadrupole and scissors modes at unitarity to experimental data obtained by the Innsbruck group. It turns out that the inclusion of fourth-order moments clearly improves the agreement with the experimental data. In particular, the fourth-order moments reduce the effect of collisions and therefore partially compensate the effect of the enhanced in-medium cross section at low temperatures.

  17. The dilute Fermi gas is the most "perfect fluid" in Nature

    E-Print Network [OSTI]

    Gabriel Wlaz?owski; Wei Quan; Aurel Bulgac

    2015-07-03

    We present an ab initio calculation of the shear viscosity as a function of interaction strength in a two-component unpolarized Fermi gas near the unitary limit, within a finite temperature quantum Monte Carlo (QMC) framework and using the Kubo linear-response formalism. The shear viscosity decreases as we tune the interaction strength $1/ak_F$ from the Bardeen-Cooper-Schrieffer (BCS) side of the Feshbach resonance towards Bose-Einstein condensation (BEC) limit and it acquires the smallest value for $1/ak_F\\approx0.4$, with a minimum value of $\\left . \\frac{\\eta}{s}\\right |_{min} \\approx 0.2 \\frac{\\hbar}{k_B}$, which is about twice as small than the value reported for experiments in quark-gluon plasma $\\left . \\frac{\\eta}{s}\\right |_{QGP} \\lesssim 0.4\\frac{\\hbar}{k_B}$. The Fermi gas near unitarity thus emerges as the most "perfect fluid" so far in Nature.

  18. Magnetic breakdown and Landau level spectra of a tunable double-quantum-well Fermi surface

    SciTech Connect (OSTI)

    Simmons, J.A.; Harff, N.E.; Lyo, S.K.; Klem, J.F. [Sandia National Labs., Albuquerque, NM (United States); Boebinger, G.S.; Pfeiffer, L.N.; West, K.W. [Lucent Technologies, Murray Hill, NJ (United States). Bell Labs.

    1997-12-31

    By measuring longitudinal resistance, the authors map the Landau level spectra of double quantum wells as a function of both parallel (B{sub {parallel}}) and perpendicular (B{sub {perpendicular}}) magnetic fields. In this continuously tunable highly non-parabolic system, the cyclotron masses of the two Fermi surface orbits change in opposite directions with B{sub {parallel}}. This causes the two corresponding ladders of Landau levels formed at finite B{sub {perpendicular}} to exhibit multiple crossings. They also observe a third set of landau levels, independent of B{sub {parallel}}, which arise from magnetic breakdown of the Fermi surface. Both semiclassical and full quantum mechanical calculations show good agreement with the data.

  19. Fermi large area telescope observations of blazar 3C 279 occultations by the sun

    SciTech Connect (OSTI)

    Barbiellini, G.; Bastieri, D.; Buson, S.; Bechtol, K.; Blandford, R. D.; Borgland, A. W.; Buehler, R.; Cameron, R. A.; Chiang, J.; Bellazzini, R.; Bregeon, J.; Bruel, P.; Caraveo, P. A.; Cavazzuti, E.; Ciprini, S.; Cecchi, C.; Chaves, R. C. G.; Cheung, C. C. E-mail: phdmitry@stanford.edu; and others

    2014-04-01

    Observations of occultations of bright ?-ray sources by the Sun may reveal predicted pair halos around blazars and/or new physics, such as, e.g., hypothetical light dark matter particles—axions. We use Fermi Gamma-Ray Space Telescope (Fermi) data to analyze four occultations of blazar 3C 279 by the Sun on October 8 each year from 2008 to 2011. A combined analysis of the observations of these occultations allows a point-like source at the position of 3C 279 to be detected with significance of ?3?, but does not reveal any significant excess over the flux expected from the quiescent Sun. The likelihood ratio test rules out complete transparency of the Sun to the blazar ?-ray emission at a 3? confidence level.

  20. Strong Interaction Effects at a Fermi Surface in a Model for Voltage-Biased Bilayer Graphene

    E-Print Network [OSTI]

    Armour, Wes; Strouthos, Costas

    2015-01-01

    Monte Carlo simulation of a 2+1 dimensional model of voltage-biased bilayer graphene, consisting of relativistic fermions with chemical potential mu coupled to charged excitations with opposite sign on each layer, has exposed non-canonical scaling of bulk observables near a quantum critical point found at strong coupling. We present a calculation of the quasiparticle dispersion relation E(k) as a function of exciton source j in the same system, employing partially twisted boundary conditions to boost the number of available momentum modes. The Fermi momentum k_F and superfluid gap Delta are extracted in the limit j tends to zero for three different values of mu, and support a strongly interacting scenario at the Fermi surface with Delta of order O(mu). We propose an explanation for the observation mu < k_F in terms of a dynamical critical exponent z < 1.

  1. Strong Interaction Effects at a Fermi Surface in a Model for Voltage-Biased Bilayer Graphene

    E-Print Network [OSTI]

    Wes Armour; Simon Hands; Costas Strouthos

    2015-09-11

    Monte Carlo simulation of a 2+1 dimensional model of voltage-biased bilayer graphene, consisting of relativistic fermions with chemical potential mu coupled to charged excitations with opposite sign on each layer, has exposed non-canonical scaling of bulk observables near a quantum critical point found at strong coupling. We present a calculation of the quasiparticle dispersion relation E(k) as a function of exciton source j in the same system, employing partially twisted boundary conditions to boost the number of available momentum modes. The Fermi momentum k_F and superfluid gap Delta are extracted in the limit j tends to zero for three different values of mu, and support a strongly interacting scenario at the Fermi surface with Delta of order O(mu). We propose an explanation for the observation mu < k_F in terms of a dynamical critical exponent z < 1.

  2. Reliable reduction of Fermi-level pinning at atomically matched metal/Ge interfaces by sulfur treatment

    SciTech Connect (OSTI)

    Kasahara, K.; Yamada, S.; Miyao, M. [Department of Electronics, Kyushu University, 744 Motooka, Fukuoka 819-0395 (Japan); Sakurai, T.; Sawano, K.; Nohira, H. [Advanced Research Laboratories, Tokyo City University, 8-15-1 Todoroki, Tokyo 158-0082 (Japan); Hamaya, K., E-mail: hamaya@ee.es.osaka-u.ac.jp [Department of Electronics, Kyushu University, 744 Motooka, Fukuoka 819-0395 (Japan); Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531 (Japan)

    2014-04-28

    This study demonstrates that by using a sulfur (S) treatment on the Ge surface, a reduction in Fermi level pinning can reproducibly be achieved at atomically matched metal/Ge(111) interfaces. The Schottky barrier height for p-type Ge can be controlled by changing the metal work function despite the metal/Ge junctions. The results indicate that the combination of atomic-arrangement matching and S treatment can remove extrinsic factors influencing Fermi level pinning at metal/Ge interfaces.

  3. Enrico Fermi Achieves First Self Sustain Nuclear Chain Reaction | National

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration would like submitKansasCommunities EnergyU.S.Engineering Metal(2) Cu (3) OEnolEnol

  4. Shot-noise at a Fermi-edge singularity: Non-Markovian dynamics

    SciTech Connect (OSTI)

    Ubbelohde, N.; Maire, N.; Haug, R. J.; Roszak, K.; Hohls, F.; Novotný, T.

    2013-12-04

    For an InAs quantum dot we study the current shot noise at a Fermi-edge singularity in low temperature cross-correlation measurements. In the regime of the interaction effect the strong suppression of noise observed at zero magnetic field and the sequence of enhancement and suppression in magnetic field go beyond a Markovian master equation model. Qualitative and quantitative agreement can however be achieved by a generalized master equation model taking non-Markovian dynamics into account.

  5. Hybrid Monte Carlo with Wilson Dirac operator on the Fermi GPU

    E-Print Network [OSTI]

    Abhijit Chakrabarty; Pushan Majumdar

    2012-07-10

    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.

  6. Quantum fluctuations in the BCS-BEC crossover of two-dimensional Fermi gases

    E-Print Network [OSTI]

    He, Lianyi; Cao, Gaoqing; Hu, Hui; Liu, Xia-Ji

    2015-01-01

    We present a theoretical study of the ground state of the BCS-BEC crossover in dilute two-dimensional Fermi gases. While the mean-field theory provides a simple and analytical equation of state, the pressure is equal to that of a noninteracting Fermi gas in the entire BCS-BEC crossover, which is not consistent with the features of the weakly interacting Bose condensate in the BEC limit and the weakly interacting Fermi liquid in the BCS limit. The inadequacy of the 2D mean-field theory indicates that the quantum fluctuations are much more pronounced than those in 3D. In this work, we show that the inclusion of the Gaussian quantum fluctuations naturally recovers the above features in both the BEC and BCS limits. In the BEC limit, the missing logarithmic dependence on the boson chemical potential is recovered by the quantum fluctuations. Near the quantum phase transition from the vacuum to the BEC phase, we compare our equation of state with the known grand canonical equation of state of 2D Bose gases and deter...

  7. Polaronic atom-trimer continuity in three-component Fermi gases

    E-Print Network [OSTI]

    Nishida, Yusuke

    2014-01-01

    Recently it has been proposed that three-component Fermi gases may exhibit a new type of crossover physics in which an unpaired Fermi sea of atoms smoothly evolves into that of trimers in addition to the ordinary BCS-BEC crossover of condensed pairs. Here we study its corresponding polaron problem in which a single impurity atom of one component interacts with condensed pairs of the other two components with equal populations. By developing a variational approach in the vicinity of a narrow Feshbach resonance, we show that the impurity atom smoothly changes its character from atom to trimer with increasing the attraction and eventually there is a sharp transition to dimer. The emergent polaronic atom-trimer continuity can be probed in ultracold atoms experiments with the inverse radio-frequency spectroscopy. Our novel crossover wave function properly incorporating the polaronic atom-trimer continuity will provide a useful basis to further investigate the phase diagram of three-component Fermi gases in more ge...

  8. Spectral zeta function and non-perturbative effects in ABJM Fermi-gas

    E-Print Network [OSTI]

    Hatsuda, Yasuyuki

    2015-01-01

    The exact partition function in ABJM theory on three-sphere can be regarded as a canonical partition function of a non-interacting Fermi-gas with an unconventional Hamiltonian. All the information on the partition function is encoded in the discrete spectrum of this Hamiltonian. We explain how (quantum mechanical) non-perturbative corrections in the Fermi-gas system appear from a spectral consideration. Basic tools in our analysis are a Mellin-Barnes type integral representation and a spectral zeta function. From a consistency with known results, we conjecture that the spectral zeta function in the ABJM Fermi-gas has an infinite number of "non-perturbative" poles, which are invisible in the semi-classical expansion of the Planck constant. We observe that these poles indeed appear after summing up perturbative corrections. As a consequence, the perturbative resummation of the spectral zeta function causes non-perturbative corrections to the grand canonical partition function. We also present another example as...

  9. Search for Early Gamma-ray Production in Supernovae Located in a Dense Circumstellar Medium with the Fermi LAT

    E-Print Network [OSTI]

    ,

    2015-01-01

    Supernovae (SNe) exploding in a dense circumstellar medium (CSM) are hypothesized to accelerate cosmic rays in collisionless shocks and emit GeV gamma rays and TeV neutrinos on a time scale of several months. We perform the first systematic search for gamma-ray emission in Fermi LAT data in the energy range from 100 MeV to 300 GeV from the ensemble of 147 SNe Type IIn exploding in dense CSM. We search for a gamma-ray excess at each SNe location in a one year time window. In order to enhance a possible weak signal, we simultaneously study the closest and optically brightest sources of our sample in a joint-likelihood analysis in three different time windows (1 year, 6 months and 3 months). For the most promising source of the sample, SN 2010jl (PTF10aaxf), we repeat the analysis with an extended time window lasting 4.5 years. We do not find a significant excess in gamma rays for any individual source nor for the combined sources and provide model-independent flux upper limits for both cases. In addition, we de...

  10. Updated Search for Spectral Lines from Galactic Dark Matter Interactions with Pass 8 Data from the Fermi Large Area Telescope

    E-Print Network [OSTI]

    ,

    2015-01-01

    Dark matter in the Milky Way may annihilate directly into gamma rays, producing a monoenergetic spectral line. Therefore, detecting such a signature would be strong evidence for dark matter annihilation or decay. We search for spectral lines in the Fermi Large Area Telescope observations of the Milky Way halo in the energy range 200 MeV to 500 GeV using analysis methods from our most recent line searches. The main improvements relative to previous works are our use of 5.8 years of data reprocessed with the Pass 8 event-level analysis and the additional data resulting from the modified observing strategy designed to increase exposure of the Galactic center region. We searched in five sky regions selected to optimize sensitivity to different theoretically-motivated dark matter scenarios and find no significant detections. In addition to presenting the results from our search for lines, we also investigate the previously reported tentative detection of a line at 133 GeV using the new Pass 8 data.

  11. Search for Gamma-Ray Emission from DES Dwarf Spheroidal Galaxy Candidates with Fermi-LAT Data

    E-Print Network [OSTI]

    The Fermi-LAT Collaboration; The DES Collaboration; :; A. Drlica-Wagner; A. Albert; K. Bechtol; M. Wood; L. Strigari; M. Sanchez-Conde; L. Baldini; R. Essig; J. Cohen-Tanugi; B. Anderson; R. Bellazzini; E. D. Bloom; R. Caputo; C. Cecchi; E. Charles; J. Chiang; J. Conrad; A. de Angelis; S. Funk; P. Fusco; F. Gargano; N. Giglietto; F. Giordano; S. Guiriec; M. Gustafsson; M. Kuss; F. Loparco; P. Lubrano; N. Mirabal; T. Mizuno; A. Morselli; T. Ohsugi; E. Orlando; M. Persic; S. Raino; F. Spada; D. J. Suson; G. Zaharijas; S. Zimmer; T. Abbott; S. Allam; E. Balbinot; A. H. Bauer; A. Benoit-Levy; R. A. Bernstein; G. M. Bernstein; E. Bertin; D. Brooks; E. Buckley-Geer; D. L. Burke; A. Carnero Rosell; F. J. Castander; R. Covarrubias; C. B. D'Andrea; L. N. da Costa; D. L. DePoy; S. Desai; H. T. Diehl; C. E Cunha; T. F. Eifler; J. Estrada; A. E. Evrard; A. Fausti Neto; E. Fernandez; D. A. Finley; B. Flaugher; J. Frieman; E. Gaztanaga; D. Gerdes; D. Gruen; R. A. Gruendl; G. Gutierrez; K. Honscheid; B. Jain; D. James; T. Jeltema; S. Kent; R. Kron; K. Kuehn; N. Kuropatkin; O. Lahav; T. S. Li; E. Luque; M. A. G. Maia; M. Makler; M. March; J. Marshall; P. Martini; K. W. Merritt; C. Miller; R. Miquel; J. Mohr; E. Neilsen; B. Nord; R. Ogando; J. Peoples; D. Petravick; A. Pieres; A. A. Plazas; A. Queiroz; A. K. Romer; A. Roodman; E. S. Rykoff; M. Sako; E. Sanchez; B. Santiago; V. Scarpine; M. Schubnell; I. Sevilla; R. C. Smith; M. Soares-Santos; F. Sobreira; E. Suchyta; M. E. C. Swanson; G. Tarle; J. Thaler; D. Thomas; D. Tucker; A. Walker; R. H. Wechsler; W. Wester; P. Williams; B. Yanny; J. Zuntz

    2015-03-19

    Due to their proximity, high dark matter content, and apparent absence of non-thermal processes, Milky Way dwarf spheroidal satellite galaxies (dSphs) are excellent targets for the indirect detection of dark matter. Recently, eight new dSph candidates were discovered using the first year of data from the Dark Energy Survey (DES). We searched for gamma-ray emission coincident with the positions of these new objects in six years of Fermi Large Area Telescope data. We found no significant excesses of gamma-ray emission. Under the assumption that the DES candidates are dSphs with dark matter halo properties similar to the known dSphs, we computed individual and combined limits on the velocity-averaged dark matter annihilation cross section for these new targets. If confirmed, they will constrain the annihilation cross section to lie below the thermal relic cross section for dark matter particles with masses < 20 GeV annihilating via the b-bbar or tau+tau- channels.

  12. Search for Gamma-Ray Emission from DES Dwarf Spheroidal Galaxy Candidates with Fermi-LAT Data

    E-Print Network [OSTI]

    :,; Albert, A; Bechtol, K; Wood, M; Strigari, L; Sanchez-Conde, M; Baldini, L; Essig, R; Cohen-Tanugi, J; Anderson, B; Bellazzini, R; Bloom, E D; Caputo, R; Cecchi, C; Charles, E; Chiang, J; Conrad, J; de Angelis, A; Funk, S; Fusco, P; Gargano, F; Giglietto, N; Giordano, F; Guiriec, S; Gustafsson, M; Kuss, M; Loparco, F; Lubrano, P; Mirabal, N; Mizuno, T; Morselli, A; Ohsugi, T; Orlando, E; Persic, M; Raino, S; Spada, F; Suson, D J; Zaharijas, G; Zimmer, S; Abbott, T; Allam, S; Balbinot, E; Bauer, A H; Benoit-Levy, A; Bernstein, R A; Bernstein, G M; Bertin, E; Brooks, D; Buckley-Geer, E; Burke, D L; Rosell, A Carnero; Castander, F J; Covarrubias, R; D'Andrea, C B; da Costa, L N; DePoy, D L; Desai, S; Diehl, H T; Cunha, C E; Eifler, T F; Estrada, J; Evrard, A E; Neto, A Fausti; Fernandez, E; Finley, D A; Flaugher, B; Frieman, J; Gaztanaga, E; Gerdes, D; Gruen, D; Gruendl, R A; Gutierrez, G; Honscheid, K; Jain, B; James, D; Jeltema, T; Kent, S; Kron, R; Kuropatkin, N; Lahav, O; Li, T S; Luque, E; Maia, M A G; Makler, M; March, M; Marshall, J; Martini, P; Merritt, K W; Miller, C; Miquel, R; Mohr, J; Neilsen, E; Nord, B; Ogando, R; Peoples, J; Petravick, D; Pieres, A; Plazas, A A; Queiroz, A; Romer, A K; Roodman, A; Rykoff, E S; Sako, M; Sanchez, E; Santiago, B; Scarpine, V; Schubnell, M; Sevilla, I; Smith, R C; Soares-Santos, M; Sobreira, F; Suchyta, E; Swanson, M E C; Tarle, G; Thaler, J; Thomas, D; Tucker, D; Walker, A; Wechsler, R H; Wester, W; Williams, P; Yanny, B; Zuntz, J

    2015-01-01

    Due to their proximity, high dark matter content, and apparent absence of non-thermal processes, Milky Way dwarf spheroidal satellite galaxies (dSphs) are excellent targets for the indirect detection of dark matter. Recently, eight new dSph candidates were discovered using the first year of data from the Dark Energy Survey (DES). We searched for gamma-ray emission coincident with the positions of these new objects in six years of Fermi Large Area Telescope data. We found no significant excesses of gamma-ray emission. Under the assumption that the DES candidates are dSphs with dark matter halo properties similar to the known dSphs, we computed individual and combined limits on the velocity-averaged dark matter annihilation cross section for these new targets. If confirmed, they will constrain the annihilation cross section to lie below the thermal relic cross section for dark matter particles with masses < 20 GeV annihilating via the b-bbar or tau+tau- channels.

  13. The Fermi-GBM X-ray burst monitor: thermonuclear bursts from 4U 0614+09

    E-Print Network [OSTI]

    Linares, M; Jenke, P; van der Horst, A J; Camero-Arranz, A; Kouveliotou, C; Chakrabarty, D; Beklen, E; Bhat, P N; Briggs, M S; Finger, M; Paciesas, W; Preece, R; von Kienlin, A; Wilson-Hodge, C A

    2012-01-01

    Thermonuclear bursts from slowly accreting neutron stars (NSs) have proven difficult to detect, yet they are potential probes of the thermal properties of the neutron star interior. During the first year of a systematic all-sky search for X-ray bursts using the Gamma-ray Burst Monitor (GBM) 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 d (68% confidence interval) between March 2010 and March 2011, classified all bursts as normal duration bursts and placed a lower limit on the recurrence time of long/intermediate bursts of 62 d (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 bu...

  14. Search for Gamma-ray Production in Supernovae Located in a Dense Circumstellar Medium with the Fermi-LAT

    E-Print Network [OSTI]

    ,

    2015-01-01

    Supernovae (SNe) exploding in a dense circumstellar medium (CSM) are predicted to accelerate cosmic rays in collisionless shocks and emit GeV gamma rays and TeV neutrinos on a time scale of several months. Here we summarize the results of the first systematic search for gamma-ray emission in Fermi-LAT data in the energy range from 100 MeV to 300 GeV from a large sample of SNe exploding in dense CSM. We search for a gamma-ray excess at the position of 147 SNe Type IIn in a one year time window after the optical peak time. In addition we combine the closest and optically brightest sources of our sample in a joint likelihood analysis in three different time windows (3, 6 and 12 months). No excess gamma-ray emission is found and limits on the gamma-ray luminosity and the ratio of gamma-ray to optical luminosity are presented.

  15. Search for Gamma-Ray Emission from DES Dwarf Spheroidal Galaxy Candidates with Fermi-LAT Data

    E-Print Network [OSTI]

    The Fermi-LAT Collaboration; The DES Collaboration; :; A. Drlica-Wagner; A. Albert; K. Bechtol; M. Wood; L. Strigari; M. Sanchez-Conde; L. Baldini; R. Essig; J. Cohen-Tanugi; B. Anderson; R. Bellazzini; E. D. Bloom; R. Caputo; C. Cecchi; E. Charles; J. Chiang; A. de Angelis; S. Funk; P. Fusco; F. Gargano; N. Giglietto; F. Giordano; S. Guiriec; M. Gustafsson; M. Kuss; F. Loparco; P. Lubrano; N. Mirabal; T. Mizuno; A. Morselli; T. Ohsugi; E. Orlando; M. Persic; S. Raino; N. Sehgal; F. Spada; D. J. Suson; G. Zaharijas; S. Zimmer; T. Abbott; S. Allam; E. Balbinot; A. H. Bauer; A. Benoit-Levy; R. A. Bernstein; G. M. Bernstein; E. Bertin; D. Brooks; E. Buckley-Geer; D. L. Burke; A. Carnero Rosell; F. J. Castander; R. Covarrubias; C. B. D'Andrea; L. N. da Costa; D. L. DePoy; S. Desai; H. T. Diehl; C. E Cunha; T. F. Eifler; J. Estrada; A. E. Evrard; A. Fausti Neto; E. Fernandez; D. A. Finley; B. Flaugher; J. Frieman; E. Gaztanaga; D. Gerdes; D. Gruen; R. A. Gruendl; G. Gutierrez; K. Honscheid; B. Jain; D. James; T. Jeltema; S. Kent; R. Kron; K. Kuehn; N. Kuropatkin; O. Lahav; T. S. Li; E. Luque; M. A. G. Maia; M. Makler; M. March; J. Marshall; P. Martini; K. W. Merritt; C. Miller; R. Miquel; J. Mohr; E. Neilsen; B. Nord; R. Ogando; J. Peoples; D. Petravick; A. Pieres; A. A. Plazas; A. Queiroz; A. K. Romer; A. Roodman; E. S. Rykoff; M. Sako; E. Sanchez; B. Santiago; V. Scarpine; M. Schubnell; I. Sevilla; R. C. Smith; M. Soares-Santos; F. Sobreira; E. Suchyta; M. E. C. Swanson; G. Tarle; J. Thaler; D. Thomas; D. Tucker; A. Walker; R. H. Wechsler; W. Wester; P. Williams; B. Yanny; J. Zuntz

    2015-08-16

    Due to their proximity, high dark-matter content, and apparent absence of non-thermal processes, Milky Way dwarf spheroidal satellite galaxies (dSphs) are excellent targets for the indirect detection of dark matter. Recently, eight new dSph candidates were discovered using the first year of data from the Dark Energy Survey (DES). We searched for gamma-ray emission coincident with the positions of these new objects in six years of Fermi Large Area Telescope data. We found no significant excesses of gamma-ray emission. Under the assumption that the DES candidates are dSphs with dark matter halo properties similar to the known dSphs, we computed individual and combined limits on the velocity-averaged dark matter annihilation cross section for these new targets. If the estimated dark-matter content of these dSph candidates is confirmed, they will constrain the annihilation cross section to lie below the thermal relic cross section for dark matter particles with masses < 20 GeV annihilating via the b-bbar or tau+tau- channels.

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

    SciTech Connect (OSTI)

    Abdo, A.A.

    2011-08-19

    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.

  17. Neutral current quasielastic (anti)neutrino scattering beyond the Fermi gas model at MiniBooNE and BNL kinematics

    E-Print Network [OSTI]

    M. V. Ivanov; A. N. Antonov; M. B. Barbaro; C. Giusti; A. Meucci; J. A. Caballero; R. Gonzalez-Jimenez; E. Moya de Guerra; J. M. Udias

    2015-03-14

    Neutral current quasielastic (anti)neutrino scattering cross sections on a $^{12}$C target are analyzed using a realistic spectral function $S(p,E)$ that gives a scaling function in accordance with the ($e,e'$) scattering data. The spectral function accounts for the nucleon-nucleon (NN) correlations by using natural orbitals (NOs) from the Jastrow correlation method and has a realistic energy dependence. The standard value of the axial mass $M_A= 1.032$ GeV is used in all calculations. The role of the final-state interaction (FSI) on the spectral and scaling functions, as well as on the cross sections is accounted for. A comparison of the calculations with the empirical data of the MiniBooNE and BNL experiments is performed. Our results are analyzed in comparison with those when NN correlations are not included, and also with results from other theoretical approaches, such as the relativistic Fermi gas (RFG), the relativistic mean field (RMF), the relativistic Green's function (RGF), as well as with the SuperScaling Approach (SuSA) based on the analysis of quasielastic electron scattering.

  18. THE FERMI-GBM X-RAY BURST MONITOR: THERMONUCLEAR BURSTS FROM 4U 0614+09

    SciTech Connect (OSTI)

    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)

    2012-12-01

    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.

  19. FERMI RULES OUT THE INVERSE COMPTON/CMB MODEL FOR THE LARGE-SCALE JET X-RAY EMISSION OF 3C 273

    SciTech Connect (OSTI)

    Meyer, Eileen T.; Georganopoulos, Markos

    2014-01-10

    The X-ray emission mechanism in large-scale jets of powerful radio quasars has been a source of debate in recent years, with two competing interpretations: either the X-rays are of synchrotron origin, arising from a different electron energy distribution than that producing the radio to optical synchrotron component, or they are due to inverse Compton scattering of cosmic microwave background photons (IC/CMB) by relativistic electrons in a powerful relativistic jet with bulk Lorentz factor ? ? 10-20. These two models imply radically different conditions in the large-scale jet in terms of jet speed, kinetic power, and maximum energy of the particle acceleration mechanism, with important implications for the impact of the jet on the large-scale environment. A large part of the X-ray origin debate has centered on the well-studied source 3C 273. Here we present new observations from Fermi which put an upper limit on the gamma-ray flux from the large-scale jet of 3C 273 that violates at a confidence greater that 99.9% the flux expected from the IC/CMB X-ray model found by extrapolation of the UV to X-ray spectrum of knot A, thus ruling out the IC/CMB interpretation entirely for this source when combined with previous work. Further, this upper limit from Fermi puts a limit on the Doppler beaming factor of at least ? < 9, assuming equipartition fields, and possibly as low as ? < 5, assuming no major deceleration of the jet from knots A through D1.

  20. Universal energy diffusion in a quivering billiard

    E-Print Network [OSTI]

    Jeffery Demers; Christopher Jarzynski

    2015-09-15

    We introduce and study a model of time-dependent billiard systems with billiard boundaries undergoing infinitesimal wiggling motions. The so-called quivering billiard is simple to simulate, straightforward to analyze, and is a faithful representation of time-dependent billiards in the limit of small boundary displacements. We assert that when a billiard's wall motion approaches the quivering motion, deterministic particle dynamics become inherently stochastic. Particle ensembles in a quivering billiard are shown to evolve to a universal energy distribution through an energy diffusion process, regardless of the billiard's shape or dimensionality, and as a consequence universally display Fermi acceleration. Our model resolves a known discrepancy between the one-dimensional Fermi-Ulam model and the simplified static wall approximation. We argue that the quivering limit is the true fixed wall limit of the Fermi-Ulam model.

  1. Quantum fluctuations in the BCS-BEC crossover of two-dimensional Fermi gases

    E-Print Network [OSTI]

    Lianyi He; Haifeng Lv; Gaoqing Cao; Hui Hu; Xia-Ji Liu

    2015-08-14

    We present a theoretical study of the ground state of the BCS-BEC crossover in dilute two-dimensional Fermi gases. While the mean-field theory provides a simple and analytical equation of state, the pressure is equal to that of a noninteracting Fermi gas in the entire BCS-BEC crossover, which is not consistent with the features of a weakly interacting Bose condensate in the BEC limit and a weakly interacting Fermi liquid in the BCS limit. The inadequacy of the 2D mean-field theory indicates that the quantum fluctuations are much more pronounced than those in 3D. In this work, we show that the inclusion of the Gaussian quantum fluctuations naturally recovers the above features in both the BEC and the BCS limits. In the BEC limit, the missing logarithmic dependence on the boson chemical potential is recovered by the quantum fluctuations. Near the quantum phase transition from the vacuum to the BEC phase, we compare our equation of state with the known grand canonical equation of state of 2D Bose gases and determine the ratio of the composite boson scattering length $a_{\\rm B}$ to the fermion scattering length $a_{\\rm 2D}$. We find $a_{\\rm B}\\simeq 0.56 a_{\\rm 2D}$, in good agreement with the exact four-body calculation. We compare our equation of state in the BCS-BEC crossover with recent results from the quantum Monte Carlo simulations and the experimental measurements and find good agreements.

  2. The influence of pairing correlations on the isospin symmetry breaking corrections of superallowed Fermi beta decays

    SciTech Connect (OSTI)

    Cal Latin-Small-Letter-Dotless-I k, A. E.; Gerceklioglu, M.; Selam, C.

    2013-05-15

    Within the framework of quasi-particle random phase approximation, the isospin breaking correction of superallowed 0{sup +} {yields} 0{sup +} beta decay and unitarity of Cabibbo-Kobayashi-Maskawa mixing matrix have been investigated. The broken isotopic symmetry of nuclear part of Hamiltonian has been restored by Pyatov's method. The isospin symmetry breaking correction with pairing correlations has been compared with the previous results without pairing. The effect of pairing interactions has been examined for nine superallowed Fermi beta decays; their parent nuclei are {sup 26}Al, {sup 34}Cl, {sup 38}K, {sup 42}Sc, {sup 46}V, {sup 50}Mn, {sup 54}Co, {sup 62}Ga, {sup 74}Rb.

  3. Microsoft Word - Fermi First Light Review_Final Corrections.doc

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefield MunicipalTechnical Report:Speeding accessby aLED Street LightingFrom theHighI _sEFFECT83InitialFermi

  4. Fermi National Accelerator Laboratory | U.S. DOE Office of Science (SC)

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  5. Fermi National Accelerator Laboratory | U.S. DOE Office of Science (SC)

    Office of Science (SC) Website

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  6. Fermi National Accelerator Laboratory | U.S. DOE Office of Science (SC)

    Office of Science (SC) Website

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  7. Fermi National Accelerator Laboratory | U.S. DOE Office of Science (SC)

    Office of Science (SC) Website

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  8. Fermi National Accelerator Laboratory | U.S. DOE Office of Science (SC)

    Office of Science (SC) Website

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power AdministrationRobust,Field-effectWorkingLosThe 26thIWalterOptimizing(SC)Fermi National

  9. Fermi National Accelerator Laboratory FERMILAB-Conf-95/276-E

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

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  10. Fermi Site Office EA / EIS | U.S. DOE Office of Science (SC)

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration would likeUniverse (Journal Article) | SciTech Connect Large Area TelescopeAdditional,Fermi

  11. Isospin transport in 84Kr + 112,124Sn collisions at Fermi energies

    E-Print Network [OSTI]

    S. Barlini; S. Piantelli; G. Casini; P. R. Maurenzig; A. Olmi; M. Bini; S. Carboni; G. Pasquali; G. Poggi; A. A. Stefanini; R. Bougault; E. Bonnet; B. Borderie; A. Chbihi; J. D. Frankland; D. Gruyer; O. Lopez; N. Le Neindre; M. Parlog; M. F. Rivet; E. Vient; E. Rosato; G. Spadaccini; M. Vigilante; M. Bruno; T. Marchi; L. Morelli; M. Cinausero; M. Degerlier; F. Gramegna; T. Kozik; T. Twarog; R. Alba; C. Maiolino; D. Santonocito

    2013-01-18

    Isotopically resolved fragments with Z<=20 have been studied with high resolution telescopes in a test run for the FAZIA collaboration. The fragments were produced by the collision of a 84Kr beam at 35 MeV/nucleon with a n-rich (124Sn) and a n-poor (112Sn) target. The fragments, detected close to the grazing angle, are mainly emitted from the phase-space region of the projectile. The fragment isotopic content clearly depends on the n-richness of the target and it is a direct evidence of isospin diffusion between projectile and target. The observed enhanced neutron richness of light fragments emitted from the phase-space region close to the center of mass of the system can be interpreted as an effect of isospin drift in the diluted neck region.

  12. Properties of the Initial Participant Matter Interaction Zone in Near Fermi-Energy Heavy Ion Collisions

    E-Print Network [OSTI]

    J. Wang; T. Keutgen; R. Wada; K. Hagel; S. Kowalski; T. Materna; L. Qin; Z. Chen; J. B. Natowitz; Y. G. Ma; M. Murray; A. Keksis; E. Martin; A. Ruangma; D. V. Shetty; G. Souliotis; M. Veselsky; E. M. Winchester; S. J. Yennello; D. Fabris; M. Lunardon; S. Moretto; G. Nebbia; S. Pesente; V. Rizzi; G. Viesti; M. Cinausero; G. Prete; J. Cibor; W. Zipper; Z. Majka; P. Staszel; Y. El Masri; R. Alfarro; A. Martinez-Davalos; A. Menchaca-Rocha; A. Ono

    2006-03-07

    The sizes, temperatures and free neutron to proton ratios of the initial interaction zones produced in the collisions of 40 MeV/nucleon $^{40}$Ar + $^{112}$Sn and 55 MeV/nucleon$^{27}$Al + $^{124}$Sn are derived using total detected neutron plus charged particle multiplicity as a measure of the impact parameter range and number of participant nucleons. The size of the initial interaction zone, determined from a coalescence model analysis, increases significantly with decreasing impact parameter. The temperatures and free neutron to proton ratios in the interaction zones are relatively similar for different impact parameter ranges and evolve in a similar fashion.

  13. Ternary Breaking of the Reaction System in Heavy-Ion Collisions below the Fermi Energy 

    E-Print Network [OSTI]

    Cammarata, Paul Joseph

    2015-01-12

    the angular distributions of the breakup. This dependence has been shown to act as a surrogate for the impact parameter of the collision. Additionally, the velocity of the resultant projectile-like fragment plays a key role in sorting out the dynamical vs...

  14. Fermi Gamma-Ray Space Telescope: High-Energy Results From the First Year

    Office of Scientific and Technical Information (OSTI)

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  15. Fermi Observations of High-Energy Gamma-Ray Emission From GRB 080825C

    Office of Scientific and Technical Information (OSTI)

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  16. Fermi Observations of High-Energy Gamma-Ray Emission From GRB 080825C

    Office of Scientific and Technical Information (OSTI)

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  17. Fermi Observations of High-Energy Gamma-Ray Emission from GRB 080916C

    Office of Scientific and Technical Information (OSTI)

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  18. Fermi Observations of High-Energy Gamma-Ray Emission from GRB 080916C

    Office of Scientific and Technical Information (OSTI)

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

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  20. Fermi Gamma-Ray Space Telescope: High-Energy Results From the First Year

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  1. Time-resolved analysis of Fermi gamma-ray bursts with fast- and slow-cooled synchrotron photon models

    SciTech Connect (OSTI)

    Burgess, J. M.; Preece, R. D.; Connaughton, V.; Briggs, M. S.; Goldstein, A.; Bhat, P. N.; Paciesas, W. S.; Xiong, S. [University of Alabama in Huntsville, 320 Sparkman Drive, Huntsville, AL 35899 (United States); Greiner, J.; Gruber, D.; Kienlin, A.; Rau, A. [Max-Planck-Institut für extraterrestrische Physik, Giessenbachstrasse 1, D-85748 Garching (Germany); Kouveliotou, C. [Space Science Office, VP62, NASA/Marshall Space Flight Center, Huntsville, AL 35812 (United States); McGlynn, S. [Exzellence Cluster "Universe," Technische Universitt Mnchen, Boltzmannstrasse 2, D-85748, Garching (Germany); Meegan, C. A. [Universities Space Research Association, 320 Sparkman Drive, Huntsville, AL 35899 (United States); Axelsson, M. [Department of Astronomy, Stockholm University, SE-106 91 Stockholm (Sweden); Baring, M. G. [Rice University, Department of Physics and Astronomy, MS-108, P.O. Box 1892, Houston, TX 77251 (United States); Dermer, C. D. [Space Science Division, Naval Research Laboratory, Washington, DC 20375-5352 (United States); Iyyani, S. [The Oskar Klein Centre for Cosmoparticle Physics, AlbaNova, SE-106 91 Stockholm (Sweden); Kocevski, D., E-mail: james.m.burgess@nasa.gov, E-mail: Rob.Preece@nasa.gov, E-mail: shabuiyyani@gmail.com, E-mail: baring@rice.edu [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); and others

    2014-03-20

    Time-resolved spectroscopy is performed on eight bright, long gamma-ray bursts (GRBs) dominated by single emission pulses that were observed with the Fermi Gamma-Ray Space Telescope. Fitting the prompt radiation of GRBs by empirical spectral forms such as the Band function leads to ambiguous conclusions about the physical model for the prompt radiation. Moreover, the Band function is often inadequate to fit the data. The GRB spectrum is therefore modeled with two emission components consisting of optically thin non-thermal synchrotron radiation from relativistic electrons and, when significant, thermal emission from a jet photosphere, which is represented by a blackbody spectrum. To produce an acceptable fit, the addition of a blackbody component is required in five out of the eight cases. We also find that the low-energy spectral index ? is consistent with a synchrotron component with ? = –0.81 ± 0.1. This value lies between the limiting values of ? = –2/3 and ? = –3/2 for electrons in the slow- and fast-cooling regimes, respectively, suggesting ongoing acceleration at the emission site. The blackbody component can be more significant when using a physical synchrotron model instead of the Band function, illustrating that the Band function does not serve as a good proxy for a non-thermal synchrotron emission component. The temperature and characteristic emission-region size of the blackbody component are found to, respectively, decrease and increase as power laws with time during the prompt phase. In addition, we find that the blackbody and non-thermal components have separate temporal behaviors as far as their respective flux and spectral evolutions.

  2. Casimir interaction between normal or superfluid grains in the Fermi sea

    E-Print Network [OSTI]

    Andreas Wirzba; Aurel Bulgac; Piotr Magierski

    2005-11-07

    We report on a new force that acts on cavities (literally empty regions of space) when they are immersed in a background of non-interacting fermionic matter fields. The interaction follows from the obstructions to the (quantum mechanical) motions of the fermions caused by the presence of bubbles or other (heavy) particles in the Fermi sea, as, for example, nuclei in the neutron sea in the inner crust of a neutron star or superfluid grains in a normal Fermi liquid. The effect resembles the traditional Casimir interaction between metallic mirrors in the vacuum. However, the fluctuating electromagnetic fields are replaced by fermionic matter fields. We show that the fermionic Casimir problem for a system of spherical cavities can be solved exactly, since the calculation can be mapped onto a quantum mechanical billiard problem of a point-particle scattered off a finite number of non-overlapping spheres or disks. Finally we generalize the map method to other Casimir systems, especially to the case of a fluctuating scalar field between two spheres or a sphere and a plate under Dirichlet boundary conditions.

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

    E-Print Network [OSTI]

    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; Tibaldo, L; Torres, D; Torresi, E; Tosti, G; Troja, E; Uchiyama, Y; Vianello, G; Winer, B; Wood, K; Zimmer, S

    2015-01-01

    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., ...

  4. Direct constraints on minimal supersymmetry from Fermi-LAT observations of the dwarf galaxy Segue 1

    SciTech Connect (OSTI)

    Scott, Pat; Conrad, Jan; Edsjö, Joakim; Bergström, Lars; Akrami, Yashar; Farnier, Christian E-mail: conrad@fysik.su.se E-mail: lbe@fysik.su.se E-mail: yashar@fysik.su.se

    2010-01-01

    The dwarf galaxy Segue 1 is one of the most promising targets for the indirect detection of dark matter. Here we examine what constraints 9 months of Fermi-LAT gamma-ray observations of Segue 1 place upon the Constrained Minimal Supersymmetric Standard Model (CMSSM), with the lightest neutralino as the dark matter particle. We use nested sampling to explore the CMSSM parameter space, simultaneously fitting other relevant constraints from accelerator bounds, the relic density, electroweak precision observables, the anomalous magnetic moment of the muon and B-physics. We include spectral and spatial fits to the Fermi observations, a full treatment of the instrumental response and its related uncertainty, and detailed background models. We also perform an extrapolation to 5 years of observations, assuming no signal is observed from Segue 1 in that time. Results marginally disfavour models with low neutralino masses and high annihilation cross-sections. Virtually all of these models are however already disfavoured by existing experimental or relic density constraints.

  5. Direct Constraints on Minimal Supersymmetry from Fermi-LAT Observations of the Dwarf Galaxy Segue 1

    E-Print Network [OSTI]

    Pat Scott; Jan Conrad; Joakim Edsjö; Lars Bergström; Christian Farnier; Yashar Akrami

    2009-12-15

    The dwarf galaxy Segue 1 is one of the most promising targets for the indirect detection of dark matter. Here we examine what constraints 9 months of Fermi-LAT gamma-ray observations of Segue 1 place upon the Constrained Minimal Supersymmetric Standard Model (CMSSM), with the lightest neutralino as the dark matter particle. We use nested sampling to explore the CMSSM parameter space, simultaneously fitting other relevant constraints from accelerator bounds, the relic density, electroweak precision observables, the anomalous magnetic moment of the muon and B-physics. We include spectral and spatial fits to the Fermi observations, a full treatment of the instrumental response and its related uncertainty, and detailed background models. We also perform an extrapolation to 5 years of observations, assuming no signal is observed from Segue 1 in that time. Results marginally disfavour models with low neutralino masses and high annihilation cross-sections. Virtually all of these models are however already disfavoured by existing experimental or relic density constraints.

  6. Constraining the Milky Way dark matter density profile with gamma-rays with Fermi-LAT

    SciTech Connect (OSTI)

    Bernal, Nicolás [Bethe Center for Theoretical Physics and Physikalisches Institut, Universität Bonn, Nußallee 12, D-53115 Bonn (Germany); Palomares-Ruiz, Sergio, E-mail: nicolas@th.physik.uni-bonn.de, E-mail: sergio.palomares.ruiz@ist.utl.pt [Centro de Física Teórica de Partículas (CFTP), Instituto Superior Técnico, Avenida Rovisco Pais 1, 1049-001 Lisboa (Portugal)

    2012-01-01

    We study the abilities of the Fermi-LAT instrument on board of the Fermi mission to simultaneously constrain the Milky Way dark matter density profile and some dark matter particle properties, as annihilation cross section, mass and branching ratio into dominant annihilation channels. A single dark matter density profile is commonly assumed to determine the capabilities of gamma-ray experiments to extract dark matter properties or to set limits on them. However, our knowledge of the Milky Way halo is far from perfect, and thus in general, the obtained results are too optimistic. Here, we study the effect these astrophysical uncertainties would have on the determination of dark matter particle properties and conversely, we show how gamma-ray searches could also be used to learn about the structure of the Milky Way halo, as a complementary tool to other type of observational data that study the gravitational effect caused by the presence of dark matter. In addition, we also show how these results would improve if external information on the annihilation cross section and on the local dark matter density were included and compare our results with the predictions from numerical simulations.

  7. Multi-wavelength features of Fermi Bubbles as signatures of a Galactic wind

    E-Print Network [OSTI]

    Sarkar, Kartick Chandra; Sharma, Prateek

    2015-01-01

    Using hydrodynamical simulations, we show that an episode of star formation in the center of the Milky Way, with a star-formation-rate (SFR) $\\sim 0.5$ M$_\\odot$ yr$^{-1}$ for $\\sim 30$ Myr, can produce bubbles that resemble the Fermi Bubbles (FBs), when viewed from the solar position. The morphology, extent and multi-wavelength observations of FBs, especially X-rays, constrain various physical parameters such as SFR, age, and the circum-galactic medium (CGM) density. We show that the interaction of the CGM with the Galactic wind driven by a star formation in the central region can explain the observed surface brightness and morphological features of X-rays associated with the Fermi Bubbles. Furthermore, assuming that cosmic ray electrons are accelerated {\\it in situ} by shocks and/or turbulence, the brightness and morphology of gamma-ray emission and the microwave haze can be explained. The kinematics of the cold and warm clumps in our model also matches with recent observations of absorption lines through t...

  8. Distinct Fermi Surface Topology and Nodeless Superconducting Gap in a Tl0:58Rb0:42Fe1:72Se2 Superconductor

    E-Print Network [OSTI]

    Tian, Weidong

    -based superconductors reported so far. The Fermi surface around the M point shows a nearly isotropic superconducting gap) superconductors [6]. It is important to explore whether the high-Tc superconductiv- ity mechanism in this new FeDistinct Fermi Surface Topology and Nodeless Superconducting Gap in a ðTl0:58Rb0:42ÞFe1:72Se2

  9. Fermi Research Alliance, LLC BAHMO: Blue Cross and Blue Shield of Illinois Coverage Period: 01/01/2015 12/31/2015 Summary of Benefits and Coverage: What this Plan Covers & What it Costs Coverage for: ALL | Plan Type: HMO

    E-Print Network [OSTI]

    Fermilab Experiment E831

    1 of 8 Fermi Research Alliance, LLC BAHMO: Blue Cross and Blue Shield of Illinois Coverage Period or plan document for additional information about excluded services. #12;2 of 8 Fermi Research Alliance

  10. Fermi Research Alliance: PPO Premium Plan Coverage Period: 01/01/2015 12/31/2015 Summary of Benefits and Coverage: What this Plan Covers & What it Costs Coverage for: ALL | Plan Type: PPO

    E-Print Network [OSTI]

    Fermilab Experiment E831

    1 of 8 Fermi Research Alliance: PPO Premium Plan Coverage Period: 01/01/2015 ­ 12/31/2015 Summary excluded services. #12;2 of 8 Fermi Research Alliance: PPO Premium Plan Coverage Period: 01/01/2015 ­ 12

  11. CEE Illinois Newsletter http://universityofillinois.createsend5.com/...mail/r/223E1D1015588E362540EF23F30FEDED/159959431C95E5BCEBAD456BEB5F1DD6[11/26/2013 11:34:34 AM

    E-Print Network [OSTI]

    Minsker, Barbara S.

    EF23F30FEDED/159959431C95E5BCEBAD456BEB5F1DD6[11/26/2013 11:34:34 AM] NEWS FROM CEE AT ILLINOIS95E5BCEBAD456BEB5F1DD6[11/26/2013 11:34:34 AM] The Department of Civil and Environmental EngineeringEF23F30FEDED/159959431C95E5BCEBAD456BEB5F1DD6[11/26/2013 11:34:34 AM] #12;

  12. Technical Design and Optimization Study for the FERMI@Elettra FEL Photoinjector

    E-Print Network [OSTI]

    Lidia, Steven M.; Penco, Giuseppe; Trovo', Mauro

    2006-01-01

    beamline layout. Energy Analyzer Optics To begin thebeam energy and energy spread. The optics will be describedand energy analyzer beamline. RF Gun and In-line Transport Optics

  13. A hadronic-leptonic model for the Fermi bubbles: Cosmic-rays in the galactic halo and radio emission

    SciTech Connect (OSTI)

    Fujita, Yutaka; Ohira, Yutaka; Yamazaki, Ryo

    2014-07-01

    We investigate non-thermal emission from the Fermi bubbles in a hadronic model. Cosmic-ray (CR) protons are accelerated at the forward shock of the bubbles. They interact with the background gas in the Galactic halo and create ?{sup 0}-decay gamma-rays and secondary electrons through proton-proton interaction. We follow the evolution of the CR protons and electrons by calculating their distribution functions. We find that the spectrum and the intensity profiles of ?{sup 0}-decay gamma-rays are consistent with observations. We predict that the shock front is located far ahead of the gamma-ray boundary of the Fermi bubbles. This naturally explains the fact that a clear temperature jump of thermal gas was not discovered at the gamma-ray boundary in recent Suzaku observations. We also consider re-acceleration of the background CRs in the Galactic halo at the shock front. We find that it can significantly affect the gamma-rays from the Fermi bubbles, unless the density of the background CRs is ? 10% of that in the Galactic disk. We indicate that secondary electrons alone cannot produce the observed radio emission from the Fermi bubbles. However, the radio emission from the outermost region of the bubbles can be explained if electrons are directly accelerated at the shock front with an efficiency of ?0.1% of that of protons.

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

    E-Print Network [OSTI]

    Dobrescu, Bogdan E.

    2009-06-02

    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...

  15. Non-Fermi Liquid Aspects of Cold and Dense QED and QCD: Equilibrium and Non-Equilibrium

    E-Print Network [OSTI]

    D. Boyanovsky; H. J. de Vega

    2000-09-14

    Infrared divergences from the exchange of dynamically screened magnetic gluons (photons) lead to the breakdown of the Fermi liquid description of the {\\em normal} state of cold and dense QCD and QED. We implement a resummation of these divergences via the renormalization group to obtain the spectral density, dispersion relation, widths and wave function renormalization of single quasiparticles near the Fermi surface. We find that all feature scaling with anomalous dimensions: $\\omega_p({k}) \\propto |k-k_F|^{\\frac{1}{1-2\\lambda}} ~ ; ~ \\Gamma(k) \\propto |k-k_F|^{\\frac{1}{1-2\\lambda}} ~;~ Z_p({k}) \\propto |k-k_F|^{\\frac{2\\lambda}{1-2\\lambda}}$ with $\\lambda = \\frac{\\alpha}{6\\pi} ~ {for QED} \\vspace{0.5 ex} ~,~ \\frac{\\alpha_s}{6\\pi} \\frac{N^2_c-1}{2N_c} \\~~{for QCD with}$. The discontinuity of the distribution function for quasiparticles near the Fermi surface vanishes. The dynamical renormalization group is implemented to study the relaxation of quasiparticles in real time. Quasiparticles with Fermi momentum have vanishing group velocity and relax with a power law with a coupling dependent anomalous dimension.

  16. The On-Orbit Calibrations for the Fermi Large Area Telescope

    SciTech Connect (OSTI)

    Abdo, Aous A.; /Naval Research Lab, Wash., D.C.; Ackermann, M.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Ajello, M.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Ampe, J.; /Naval Research Lab, Wash., D.C.; Anderson, B.; /UC, Santa Cruz; Atwood, W.B.; /UC, Santa Cruz; Axelsson, M.; /Stockholm U., OKC /Stockholm U.; Bagagli, R.; /INFN, Pisa; Baldini, L.; /INFN, Pisa; Ballet, J.; /DAPNIA, Saclay; 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; Belli, F.; /Frascati /Rome U.,Tor Vergata; Berenji, B.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bisello, D.; /INFN, Padua /Padua U. /Garching, Max Planck Inst., MPE /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Ecole Polytechnique /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /INFN, Perugia /Perugia U. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /DAPNIA, Saclay /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. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /IASF, Milan /IASF, Milan /Kalmar U. /Stockholm U., OKC /Royal Inst. Tech., Stockholm /DAPNIA, Saclay /ASDC, Frascati /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.; /more authors..

    2011-11-17

    The Large Area Telescope (LAT) on-board the Fermi Gamma-ray Space Telescope began its on-orbit operations on June 23, 2008. Calibrations, defined in a generic sense, correspond to synchronization of trigger signals, optimization of delays for latching data, determination of detector thresholds, gains and responses, evaluation of the perimeter of the South Atlantic Anomaly (SAA), measurements of live time, of absolute time, and internal and spacecraft boresight alignments. Here we describe on-orbit calibration results obtained using known astrophysical sources, galactic cosmic rays, and charge injection into the front-end electronics of each detector. Instrument response functions will be described in a separate publication. This paper demonstrates the stability of calibrations and describes minor changes observed since launch. These results have been used to calibrate the LAT datasets to be publicly released in August 2009.

  17. Anomalous specific heat jump in a two-component ultracold Fermi gas

    E-Print Network [OSTI]

    Armen Sedrakian; Herbert Müther; Artur Polls

    2006-09-20

    The thermodynamic functions of a Fermi gas with spin population imbalance are studied in the temperature-asymmetry plane in the BCS limit. The low temperature domain is characterized by anomalous enhancement of the entropy and the specific heat above their values in the unpaired state, decrease of the gap and eventual unpairing phase transition as the temperature is lowered. The unpairing phase transition induces a second jump in the specific heat, which can be measured in calorimetric experiments. While the superfluid is unstable against a supercurrent carrying state, it may sustain a metastable state if cooled adiabatically down from the stable high-temperature domain. In the latter domain the temperature dependence of the gap and related functions is analogous to the predictions of the BCS theory.

  18. Second sound and the superfluid fraction in a resonantly interacting Fermi gas

    E-Print Network [OSTI]

    Sidorenkov, Leonid A; Grimm, Rudolf; Hou, Yan-Hua; Pitaevskii, Lev; Stringari, Sandro

    2013-01-01

    Superfluidity is a macroscopic quantum phenomenon, which shows up below a critical temperature and leads to a peculiar behavior of matter, with frictionless flow, the formation of quantized vortices, and the quenching of the moment of inertia being intriguing examples. A remarkable explanation for many phenomena exhibited by a superfluid at finite temperature can be given in terms of a two-fluid mixture comprised of a normal component that behaves like a usual fluid and a superfluid component with zero viscosity and zero entropy. Important examples of superfluid systems are liquid helium and neutron stars. More recently, ultracold atomic gases have emerged as new superfluid systems with unprecedented possibilities to control interactions and external confinement. Here we report the first observation of `second sound' in an ultracold Fermi gas with resonant interactions. Second sound is a striking manifestation of the two-component nature of a superfluid and corresponds to an entropy wave, where the superfluid...

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

    ScienceCinema (OSTI)

    Simon Swordy

    2010-01-08

    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.

  20. Radio observations of the first three-month Fermi-AGN at 4.8 GHz

    E-Print Network [OSTI]

    Xiang Liu; Hua-Gang Song; Jun Liu; Zhen Ding; Nicola Marchili; Thomas P. Krichbaum; Lars Fuhrmann; Anton Zensus; Tao An

    2011-10-09

    Using the Urumqi 25m radio telescope, sources from the first three-month Fermi-LAT detected AGN catalog with declination >0 were observed in 2009 at 4.8 GHz. The radio flux density appears to correlate with the gamma-ray intensity. Intra-day variability (IDV) observations were performed in March, April and May in 2009 for selected 42 gamma-ray bright blazars, and 60% of them show evident flux variability at 4.8 GHz during the IDV observations, the IDV detection rate is higher than that in previous flat-spectrum AGN samples. The IDV appears more often in the VLBI-core dominant blazars, and the non-IDV blazars show relatively `steeper' spectral indices than the IDV blazars. Pronounced inter-month variability has been found in two BL Lac objects: J0112+2244 and J0238+1636.

  1. Orthogonality catastrophe as a consequence of qubit embedding in an ultracold Fermi gas

    SciTech Connect (OSTI)

    Goold, J. [Clarendon Laboratory, University of Oxford (United Kingdom); Physics Department, University College Cork, Cork (Ireland); Fogarty, T.; Lo Gullo, N.; Busch, Th. [Physics Department, University College Cork, Cork (Ireland); Paternostro, M. [Centre for Theoretical Atomic, Molecular and Optical Physics, Queen's University Belfast, Belfast BT7 1NN (United Kingdom)

    2011-12-15

    We investigate the behavior of a two-level atom coupled to a one-dimensional, ultracold Fermi gas. The sudden switching on of the scattering between the two entities leads to the loss of any coherence in the initial state of the impurity and we show that the exact dynamics of this process is strongly influenced by the effect of the orthogonality catastrophe within the gas. We highlight the relationship between the Loschmidt echo and the retarded Green's function - typically used to formulate the dynamical theory of the catastrophe - and demonstrate that the effect is reflected in the impurity dynamics. We show that the expected nonexponential decay of the spectral function can be observed using Ramsey interferometry on the two-level atom and comment on finite temperature effects.

  2. Second order fluid dynamics for the unitary Fermi gas from kinetic theory

    E-Print Network [OSTI]

    Thomas Schaefer

    2014-10-15

    We compute second order transport coefficients of the dilute Fermi gas at unitarity. The calculation is based on kinetic theory and the Boltzmann equation at second order in the Knudsen expansion. The second order transport coefficients describe the shear stress relaxation time, non-linear terms in the strain-stress relation, and non-linear couplings between vorticity and strain. An exact calculation in the dilute limit gives $\\tau_R=\\eta/P$, where $\\tau_R$ is the shear stress relaxation time, $\\eta$ is the shear viscosity, and $P$ is pressure. This relation is identical to the result obtained using the Bhatnagar-Gross-Krook (BGK) approximation to the collision term, but other transport coefficients are sensitive to the exact collision integral.

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

    SciTech Connect (OSTI)

    Chen, Y.

    2010-05-03

    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.

  4. Constraining Inert Triplet dark matter by the LHC and FermiLAT

    SciTech Connect (OSTI)

    Ayazi, Seyed Yaser; Firouzabadi, S. Mahdi E-mail: smmfirouz@yahoo.com

    2014-11-01

    We study collider phenomenology of inert triplet scalar dark matter at the LHC. We discuss possible decay of Higgs boson to dark matter candidate and apply current experimental data for invisible Higgs decay and R{sub ??} to constrain parameter space of our model. We also investigate constraints on dark matter coming from forthcoming measurement, R{sub Z?} and mono-Higgs production. We analytically calculate the annihilation cross section of dark matter candidate into 2? and Z? and then use FermiLAT data to put constraints on parameter space of Inert Triplet Model. We found that this limit can be stronger than the constraints provided by LUX experiment for low mass DM.

  5. Time resolved spectroscopy of SGR J1550–5418 bursts detected with Fermi/gamma-ray burst monitor

    SciTech Connect (OSTI)

    Younes, G. [Universities Space Research Association, 6767 Old Madison Pike, Suite 450, Huntsville, AL 35806 (United States); Kouveliotou, C.; Collazzi, A. [Astrophysics Office, ZP 12, NASA-Marshall Space Flight Center, Huntsville, AL 35812 (United States); Van der Horst, A. J.; Watts, A. L.; Huppenkothen, D.; Van der Klis, M.; Van Putten, T. [Astronomical Institute "Anton Pannekoek," University of Amsterdam, Postbus 94249, 1090 GE Amsterdam (Netherlands); Baring, M. G. [Department of Physics and Astronomy, Rice University, MS-108, P.O. Box 1892, Houston, TX 77251 (United States); Granot, J. [Department of Natural Sciences, The Open University of Israel, 1 University Road, P.O. Box 808, Raánana 43537 (Israel); Bhat, P. N.; Gorgone, N. [University of Alabama in Huntsville CSPAR, 320 Sparkman Drive, Huntsville, AL 35805 (United States); Gehrels, N.; Mcenery, J. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Gö?ü?, E.; Kaneko, Y.; Lin, L. [Sabanc? University, Orhanl?-Tuzla, ?stanbul 34956 (Turkey); Gruber, D.; Von Kienlin, A. [Max Planck Institute for Extraterrestrial Physics, Giessenbachstrasse, Postfach 1312, D-85748 Garching (Germany); Grunblatt, S. [University of Hawaii at Manoa, 2500 Campus Road, Honolulu, HI 96822 (United States); and others

    2014-04-10

    We report on a time-resolved spectroscopy of the 63 brightest bursts of SGR J1550–5418, detected with the Fermi/Gamma-ray Burst Monitor during its 2008-2009 intense bursting episode. We performed spectral analysis down to 4 ms timescales to characterize the spectral evolution of the bursts. Using a Comptonized model, we find that the peak energy, E {sub peak}, anti-correlates with flux, while the low-energy photon index remains constant at ? – 0.8 up to a flux limit F ? 10{sup –5} erg s{sup –1} cm{sup –2}. Above this flux value, the E {sub peak}–flux correlation changes sign, and the index positively correlates with the flux reaching ?1 at the highest fluxes. Using a two blackbody model, we find that the areas and fluxes of the two emitting regions correlate positively. Further, we study here for the first time the evolution of the temperatures and areas as a function of flux. We find that the area–kT relation follows the lines of constant luminosity at the lowest fluxes, R {sup 2}?kT {sup –4}, with a break at the higher fluxes (F > 10{sup –5.5} erg s{sup –1} cm{sup –2}). The area of the high-kT component increases with the flux while its temperature decreases, which we interpret as being due to an adiabatic cooling process. The area of the low-kT component, on the other hand, appears to saturate at the highest fluxes, toward R {sub max} ? 30 km. Assuming that crust quakes are responsible for soft gamma repeater (SGR) bursts and considering R {sub max} as the maximum radius of the emitting photon-pair plasma fireball, we relate this saturation radius to a minimum excitation radius of the magnetosphere, and we put a lower limit on the internal magnetic field of SGR J1550–5418, B {sub int} ? 4.5 × 10{sup 15} G.

  6. Testing No-Scale Supergravity with the Fermi Space Telescope LAT

    E-Print Network [OSTI]

    Tianjun Li; James A. Maxin; Dimitri V. Nanopoulos; Joel W. Walker

    2014-02-17

    We describe a methodology for testing No-Scale Supergravity by the LAT instrument onboard the Fermi Space Telescope via observation of gamma ray emissions from lightest supersymmetric (SUSY) neutralino annihilations. For our test vehicle we engage the framework of the supersymmetric grand unified model No-Scale Flipped $SU(5)$ with extra vector-like flippon multiplets derived from F-Theory, known as $\\cal{F}$-$SU(5)$. We show that through compression of the light stau and light bino neutralino mass difference, where internal bremsstrahlung (IB) photons give a dominant contribution, the photon yield from annihilation of SUSY dark matter can be elevated to a number of events potentially observable by the Fermi-LAT in the coming years. Likewise, the increased yield in No-Scale $\\cal{F}$-$SU(5)$ may also have rendered the existing observation of a 133 GeV monochromatic gamma ray line visible, if additional data should exclude systematic or statistical explanations. The question of intensity aside, No-Scale $\\cal{F}$-$SU(5)$ can indeed provide a natural weakly interacting massive particle (WIMP) candidate with a mass in the correct range to yield $\\gamma \\gamma$ and $\\gamma Z$ emission lines at $m_{\\chi} \\sim 133$ GeV and $m_{\\chi} \\sim 145$ GeV, respectively. Additionally, we elucidate the emerging empirical connection between recent Planck satellite data and No-Scale Supergravity cosmological models which mimic the Starobinsky model of inflation. Together, these experiments furnish rich alternate avenues for testing No-Scale $\\cal{F}$-$SU(5)$, and similarly structured models, the results of which may lend independent credence to observations made at the LHC.

  7. Friedel Oscillation-Induced Energy Gap Manifested as Transport Asymmetry at Monolayer-Bilayer Graphene Boundaries

    E-Print Network [OSTI]

    Feenstra, Randall

    1 Friedel Oscillation-Induced Energy Gap Manifested as Transport Asymmetry at Monolayer will first develop a general theory of the Friedel energy gap and the transport asymmetry across a boundary at the Fermi energy for electrons with wave vectors perpendicular to the interface. If the Friedel gaps on two

  8. Isospin relaxation time in heavy-ion collisions at intermediate energies 

    E-Print Network [OSTI]

    Li, Ba; Ko, Che Ming.

    1998-01-01

    Using an isospin-dependent transport model, we have studied the isospin and momentum relaxation times in the heavy residues formed in heavy-ion collisions at intermediate energies. It is found that only at incident energies below the Fermi energy...

  9. Novel technique to extract experimental symmetry free energy information of nuclear matter

    E-Print Network [OSTI]

    Mabiala, J; Bonasera, A; Cammarata, P; Hagel, K; Heilborn, L; Kohley, Z; May, L W; McIntosh, A B; Youngs, M D; Zarrella, A; Yennello, S J

    2015-01-01

    A new method of accessing information on the symmetry free energy from yields of fragments produced in Fermi-energy heavy-ion collisions is proposed. Furthermore, by means of quantum fluctuation analysis techniques, correlations between extracted symmetry free-energy coefficients with temperature and density were studied. The obtained results are consistent with those of commonly used isoscaling techniques.

  10. Observation of an electron band above the Fermi level in FeTe?.??Se?.?? from in-situ surface doping

    SciTech Connect (OSTI)

    Zhang, P.; Richard, P.; Xu, N.; Xu, Y. -M.; Ma, J.; Qian, T.; Fedorov, A. V.; Denlinger, J. D.; Gu, G. D.; Ding, H.

    2014-10-27

    We used in-situ potassium (K) evaporation to dope the surface of the iron-based superconductor FeTe?.??Se?.??. The systematic study of the bands near the Fermi level confirms that electrons are doped into the system, allowing us to tune the Fermi level of this material and to access otherwise unoccupied electronic states. In particular, we observe an electron band located above the Fermi level before doping that shares similarities with a small three-dimensional pocket observed in the cousin, heavily-electron-doped KFe??xSe? compound.

  11. The FERMI @ Elettra Technical Optimization Study: General Layout and Parameters and Physics Studies of Longitudinal Space Charge, the Spreader, the Injector, and Preliminary FEL Performance

    E-Print Network [OSTI]

    2005-01-01

    Studies of the FERMI at ELETTRA FEL Design”, G. De Ninno, B.very preliminary GENESIS runs of FEL-II output are shown infigures show a summary of runs FEL-II at 10 nm. Tapering is

  12. On the role of stochastic Fermi acceleration in setting the dissipation scale of turbulence in the interstellar medium

    E-Print Network [OSTI]

    Selkowitz, Robert I

    2007-01-01

    We consider the dissipation by Fermi acceleration of magnetosonic turbulence in the Reynolds Layer of the interstellar medium. The scale in the cascade at which electron acceleration via stochastic Fermi acceleration (STFA) becomes comparable to further cascade of the turbulence defines the inner scale. For any magnetic turbulent spectra equal to or shallower than Goldreich-Sridhar this turns out to be $\\ge 10^{12}$cm, which is much larger than the shortest length scales observed in radio scintillation measurements. While STFA for such spectra then contradict models of scintillation which appeal directly to an extended, continuous turbulent cascade, such a separation of scales is consistent with the recent work of \\citet{Boldyrev2} and \\citet{Boldyrev3} suggesting that interstellar scintillation may result from the passage of radio waves through the galactic distribution of thin ionized boundary surfaces of HII regions, rather than density variations from cascading turbulence. The presence of STFA dissipation...

  13. The electron-positron momentum density and Fermi surface of YBa sub 2 Cu sub 3 O sub 7-x

    SciTech Connect (OSTI)

    Haghighi, H.; Kaiser, J.H.; Rayner, S.; West, R.N. ); Liu, J.Z.; Shelton, R. ); Howell, R.H.; Solal, F.; Sterne, P.A.; Fluss, M.J. )

    1991-10-11

    The search for evidence of Fermi surface in the cuprate high temperature superconductors has provided the greatest challenge for the 2D ACAR technique thus far in its relatively short history. Much of the effort in both theory and experiment has focused on the Yttrium compound where the small size of samples, twinning and structural oxygen defects have made the experiments difficult, complicated the interpretation of results and led to some confusion. With the advent of good twin-free crystals that confusion has now been resolved. In this paper we shall briefly review the earlier experiments on twinned crystals and then describe in more detail, and in the context of the contemporary bandstructure theory, our recent clear resolution of a major Fermi surface section in untwinned crystals of YBa{sub 2}Cu{sub 3}O{sub 7-x}.

  14. Alleviation of fermi-level pinning effect at metal/germanium interface by the insertion of graphene layers

    SciTech Connect (OSTI)

    Baek, Seung-heon Chris; Seo, Yu-Jin; Oh, Joong Gun; Albert Park, Min Gyu; Bong, Jae Hoon; Yoon, Seong Jun; Lee, Seok-Hee, E-mail: seokheelee@ee.kaist.ac.kr [Department of Electrical Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Seo, Minsu; Park, Seung-young [Division of Materials Science, Korea Basic Science Institute (KBSI), 169-148 Daehak-ro, Yuseong-gu, Daejeon 305-333 (Korea, Republic of); Park, Byong-Guk [Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 305-701 (Korea, Republic of)

    2014-08-18

    In this paper, we report the alleviation of the Fermi-level pinning on metal/n-germanium (Ge) contact by the insertion of multiple layers of single-layer graphene (SLG) at the metal/n-Ge interface. A decrease in the Schottky barrier height with an increase in the number of inserted SLG layers was observed, which supports the contention that Fermi-level pinning at metal/n-Ge contact originates from the metal-induced gap states at the metal/n-Ge interface. The modulation of Schottky barrier height by varying the number of inserted SLG layers (m) can bring about the use of Ge as the next-generation complementary metal-oxide-semiconductor material. Furthermore, the inserted SLG layers can be used as the tunnel barrier for spin injection into Ge substrate for spin-based transistors.

  15. Fermi-LAT Upper Limit for NGC 4151 and its Implications for Physics of Hot Accretion Flow

    E-Print Network [OSTI]

    Wojaczynski, Rafal; Xie, Fu-Guo

    2015-01-01

    We present preliminary results of our analysis of the {\\it Fermi}-LAT data from the direction of NGC 4151. We find a new gamma-ray source with a statistical significance sigma > 5, shifted by 0.5degr from the position of NGC 4151. Apparently, the source was bright only during a 1.5-year period between December 2011 and June 2013 and it strongly contaminated the signal from NGC 4151. Therefore, we neglect this period in our analysis. We find two additional, persistent gamma-ray sources with high sigma, shifted from NGC 4151 by ~1.5degr and 5degr, whose presence has been recently confirmed in the Third Fermi Catalog. After subtracting the above sources, we still see a weak residual, with sigma ~< 3, at the position of NGC 4151. We derive an upper limit (UL) for the gamma-ray flux from NGC 4151 and we compare it with predictions of the ADAF model which can explain the X-ray observations of this object. We find that the Fermi UL strongly constrains non-thermal acceleration processes in hot flows as well as the...

  16. Collective mode evidence of high-spin bosonization in a trapped one-dimensional atomic Fermi gas with tunable spin

    SciTech Connect (OSTI)

    Liu, Xia-Ji Hu, Hui

    2014-11-15

    We calculate the frequency of collective modes of a one-dimensional repulsively interacting Fermi gas with high-spin symmetry confined in harmonic traps at zero temperature. This is a system realizable with fermionic alkaline-earth-metal atoms such as {sup 173}Yb, which displays an exact SU(?) spin symmetry with ??2 and behaves like a spinless interacting Bose gas in the limit of infinite spin components ???, namely high-spin bosonization. We solve the homogeneous equation of state of the high-spin Fermi system by using Bethe ansatz technique and obtain the density distribution in harmonic traps based on local density approximation. The frequency of collective modes is calculated by exactly solving the zero-temperature hydrodynamic equation. In the limit of large number of spin-components, we show that the mode frequency of the system approaches that of a one-dimensional spinless interacting Bose gas, as a result of high-spin bosonization. Our prediction of collective modes is in excellent agreement with a very recent measurement for a Fermi gas of {sup 173}Yb atoms with tunable spin confined in a two-dimensional tight optical lattice.

  17. Tracing the propagation of cosmic rays in the Milky Way halo with Fermi-LAT observations of high- and intermediate-velocity clouds

    E-Print Network [OSTI]

    Tibaldo, L

    2015-01-01

    Cosmic rays up to at least PeV energies are usually described in the framework of an elementary scenario that involves acceleration by objects that are located in the disk of the Milky Way, such as supernova remnants or massive star-forming regions, and then diffusive propagation throughout the Galaxy. Details of the propagation process are so far inferred mainly from the composition of cosmic rays measured near the Earth and then extrapolated to the whole Galaxy. The details of the propagation in the Galactic halo and the escape into the intergalactic medium remain uncertain. The densities of cosmic rays in specific locations can be traced via the gamma rays they produce in inelastic collisions with clouds of interstellar gas. Therefore, we analyze 73 months of Fermi-LAT data from 300 MeV to 10 GeV in the direction of several high- and intermediate-velocity clouds that are located in the halo of the Milky Way. These clouds are supposed to be free of internal sources of cosmic rays and hence any gamma-ray emi...

  18. A Determination of the Gamma-ray Flux and Photon Spectral Index Distributions of Blazars from the Fermi-LAT 3LAC

    E-Print Network [OSTI]

    Singal, J

    2015-01-01

    We present a determination of the distributions of gamma-ray photon flux -- the so called LogN-LogS relation -- and photon spectral index for blazars, based on the third extragalactic source catalog of the Fermi Gamma-ray Space Telescope's Large Area Telescope, and considering the photon energy range from 100 MeV to 100 GeV. The dataset consists of the 774 blazars in the so-called "Clean" sample detected with a greater than approximately seven sigma detection threshold and located above $\\pm$20 deg Galactic latitude. We use non-parametric methods verified in previous works to reconstruct the intrinsic distributions from the observed ones which account for the data truncations introduced by observational bias and includes the effects of the possible correlation between the flux and photon index. The intrinsic flux distribution can be represented by a broken power law with a high flux power-law index of -2.43$\\pm$0.08 and a low flux power-law index of -1.87$\\pm$0.10. The intrinsic photon index distribution can ...

  19. The mystery of spectral breaks: Lyman continuum absorption by photon-photon pair production in the Fermi GeV spectra of bright blazars

    SciTech Connect (OSTI)

    Stern, Boris E. [Institute for Nuclear Research, Russian Academy of Sciences, Prospekt 60-letiya Oktyabrya 7a, Moscow 117312 (Russian Federation); Poutanen, Juri, E-mail: stern.boris@gmail.com, E-mail: juri.poutanen@utu.fi [Tuorla Observatory, University of Turku, Väisäläntie 20, FI-21500 Piikkiö (Finland)

    2014-10-10

    We re-analyze Fermi/LAT ?-ray spectra of bright blazars using the new Pass 7 version of the detector response files and detect breaks at ?5 GeV in the rest-frame spectra of 3C 454.3 and possibly also 4C +21.35, associated with the photon-photon pair production absorption by the He II Lyman continuum (LyC). We also detect significant breaks at ?20 GeV associated with hydrogen LyC in both the individual spectra and the stacked redshift-corrected spectrum of several bright blazars. The detected breaks in the stacked spectra univocally prove that they are associated with atomic ultraviolet emission features of the quasar broad-line region (BLR). The dominance of the absorption by the hydrogen Ly complex over He II, a small detected optical depth, and break energy consistent with head-on collisions with LyC photons imply that the ?-ray emission site is located within the BLR, but most of the BLR emission comes from a flat disk-like structure producing little opacity. Alternatively, the LyC emission region size might be larger than the BLR size measured from reverberation mapping, and/or the ?-ray emitting region is extended. These solutions would resolve the long-standing issue of how the multi-hundred GeV photons can escape from the emission zone without being absorbed by softer photons.

  20. EIA-176 Electronic Filing System (EFS)

    Gasoline and Diesel Fuel Update (EIA)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of Natural GasAdjustments (Billion Cubic Feet) Wyoming Dry Natural GasNatural GasEIA lowers forecast for summer

  1. Reduction of Fermi level pinning and recombination at polycrystalline CdTe surfaces by laser irradiation

    SciTech Connect (OSTI)

    Simonds, Brian J.; Kheraj, Vipul; Palekis, Vasilios; Ferekides, Christos; Scarpulla, Michael A.

    2015-06-14

    Laser processing of polycrystalline CdTe is a promising approach that could potentially increase module manufacturing throughput while reducing capital expenditure costs. For these benefits to be realized, the basic effects of laser irradiation on CdTe must be ascertained. In this study, we utilize surface photovoltage spectroscopy (SPS) to investigate the changes to the electronic properties of the surface of polycrystalline CdTe solar cell stacks induced by continuous-wave laser annealing. The experimental data explained within a model consisting of two space charge regions, one at the CdTe/air interface and one at the CdTe/CdS junction, are used to interpret our SPS results. The frequency dependence and phase spectra of the SPS signal are also discussed. To support the SPS findings, low-temperature spectrally-resolved photoluminescence and time-resolved photoluminescence were also measured. The data show that a modest laser treatment of 250?W/cm{sup 2} with a dwell time of 20?s is sufficient to reduce the effects of Fermi level pinning at the surface due to surface defects.

  2. Recent progress in III-V based ferromagnetic semiconductors: Band structure, Fermi level, and tunneling transport

    SciTech Connect (OSTI)

    Tanaka, Masaaki; Ohya, Shinobu Nam Hai, Pham

    2014-03-15

    Spin-based electronics or spintronics is an emerging field, in which we try to utilize spin degrees of freedom as well as charge transport in materials and devices. While metal-based spin-devices, such as magnetic-field sensors and magnetoresistive random access memory using giant magnetoresistance and tunneling magnetoresistance, are already put to practical use, semiconductor-based spintronics has greater potential for expansion because of good compatibility with existing semiconductor technology. Many semiconductor-based spintronics devices with useful functionalities have been proposed and explored so far. To realize those devices and functionalities, we definitely need appropriate materials which have both the properties of semiconductors and ferromagnets. Ferromagnetic semiconductors (FMSs), which are alloy semiconductors containing magnetic atoms such as Mn and Fe, are one of the most promising classes of materials for this purpose and thus have been intensively studied for the past two decades. Here, we review the recent progress in the studies of the most prototypical III-V based FMS, p-type (GaMn)As and its heterostructures with focus on tunneling transport, Fermi level, and bandstructure. Furthermore, we cover the properties of a new n-type FMS, (In,Fe)As, which shows electron-induced ferromagnetism. These FMS materials having zinc-blende crystal structure show excellent compatibility with well-developed III-V heterostructures and devices.

  3. Exponential Decay and Fermi's Golden Rule from an Uncontrolled Quantum Zeno Effect

    E-Print Network [OSTI]

    P. W. Bryant

    2014-10-14

    We modify the theory of the Quantum Zeno Effect to make it consistent with the postulates of quantum mechanics. This modification allows one, throughout a sequence of observations of an excited system, to address the nature of the observable and thereby to distinguish survival from non-decay, which is necessary whenever excited states are degenerate. As a consequence, one can determine which types of measurements can possibly inhibit the exponential decay of the system. We find that continuous monitoring taken as the limit of a sequence of ideal measurements will only inhibit decay in special cases, such as in well-controlled experiments. Uncontrolled monitoring of an unstable system, however, can cause exponentially decreasing non-decay probability at all times. Furthermore, calculating the decay rate for a general sequence of observations leads to a straightforward derivation of Fermi's Golden Rule, that avoids many of the conceptual difficulties normally encountered. When multiple decay channels are available, the derivation reveals how the total decay rate naturally partitions into a sum of the decay rates for the various channels, in agreement with observations. Continuous and unavoidable monitoring of an excited system by an uncontrolled environment may therefore be a mechanism by which to explain the exponential decay law.

  4. Timing Gamma-ray Pulsars with the Fermi Large Area Telescope: Timing Noise and Astrometry

    E-Print Network [OSTI]

    Kerr, Matthew; Johnston, Simon; Shannon, Ryan; Camilo, Fernando

    2015-01-01

    We have constructed timing solutions for 81 gamma-ray pulsars covering more than five years of Fermi data. The sample includes 37 radio-quiet or radio-faint pulsars which cannot be timed with other telescopes. These timing solutions and the corresponding pulse times of arrival are prerequisites for further study, e.g. phase-resolved spectroscopy or searches for mode switches. Many gamma-ray pulsars are strongly affected by timing noise, and we present a new method for characterizing the noise process and mitigating its effects on other facets of the timing model. We present an analysis of timing noise over the population using a new metric for characterizing its strength and spectral shape, namely its time-domain correlation. The dependence of the strength on spin frequency and spin-down rate is in good agreement with previous studies. We find that noise process power spectra $S(f)$ for unrecycled pulsars are steep, with strong correlations over our entire data set and spectral indices $S(f)\\propto f^{-\\alpha...

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

    E-Print Network [OSTI]

    ,

    2011-01-01

    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) onboard the \\emph{Fermi} Gamma-ray Space Telescope. An investigation of the relationship among 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 $\\pm$ 0.6 (stat) $\\pm$ 1.2 (sys) GeV, and photon indices of 2.10 $\\pm$ 0.06 (stat) $\\pm$ 0.10 (sys) below the break and 2.70 $\\pm$ 0.12 (stat) $\\pm$ 0.14...

  6. Van der Waals Equation of State with Fermi Statistics for Nuclear Matter

    E-Print Network [OSTI]

    V. Vovchenko; D. V. Anchishkin; M. I. Gorenstein

    2015-06-26

    The van der Waals (VDW) equation of state is a simple and popular model to describe the pressure function in equilibrium systems of particles with both repulsive and attractive interactions. This equation predicts an existence of a first-order liquid-gas phase transition and contains a critical point. Two steps to extend the VDW equation and make it appropriate for new physical applications are carried out in this paper: 1) the grand canonical ensemble formulation; 2) an inclusion of the quantum statistics. The VDW equation with Fermi statistics is then applied to a description of the system of interacting nucleons. The VDW parameters $a$ and $b$ are fixed to reproduce the properties of nuclear matter at saturation density $n_0=0.16$ fm$^{-3}$ and zero temperature. The model predicts a location of the critical point for the symmetric nuclear matter at temperature $T_c\\cong 19.7$ MeV and nucleon number density $n_c \\cong 0.07$ fm$^{-3}$.

  7. Blue Wings and Bumps via Fermi-like Acceleration of Lyman-alpha photons across Shocks

    E-Print Network [OSTI]

    Chung, Andrew S; Ciardi, Benedetta; Gronke, Max

    2015-01-01

    We explore the impact of Fermi-like acceleration of Lyman-alpha (Ly{\\alpha}) photons across shock fronts on the observed Ly{\\alpha} spectral line shape. We first confirm the result of Neufeld & McKee (1988) that this mechanism gives rise to extended blue wings which may have been observed in some radio galaxies. Our Monte-Carlo radiative transfer calculations further show that in a minor modification of the shell-model, in which we add an additional static shell of hydrogen, this process can naturally explain the small blue bumps observed in a subset of Ly{\\alpha} emitting galaxies, which have been difficult to explain with conventional shell-models. Blue bumps can be produced with an additional column density of static hydrogen as small as $N_{HI}^{static} \\ll N_{HI}^{shell}$, and typically occur at roughly the outflow velocity of the shell. In our model the spectra of so-called 'blue-bump objects' might reflect an evolutionary stage in which the outflows regulating the escape of Ly{\\alpha} photons are s...

  8. Models of the Prompt and High Energy Emission of GRB

    SciTech Connect (OSTI)

    Meszaros, Peter; Toma, Kenji; Wu Xuefeng; He Haoning [Center for Particle Astrophysics, Dept. of Astronomy and Astrophysics and Dept. of Physics, Pennsylvania State University, University Park, PA 16802 (United States)

    2010-10-15

    Gamma-ray bursts have been detected at photon energies up to tens of GeV. We review some recent developments in the X-ray to GeV photon phenomenology in the light of Swift and Fermi observations, and some of the theoretical models developed to explain them.

  9. Energy and Demand Savings from Implementation Costs in Industrial Facilities 

    E-Print Network [OSTI]

    Razinha, J. A.; Heffington, W. M.

    2000-01-01

    Electrical Fees EF Electricity E1 Natural Gas E2 L.P.G. E3 #1 Fuel Oil E4 #2 Fuel Oil E5 #4 Fuel Oil E6 #6 Fuel Oil E7 Coal E8 Wood E9 Paper E10 Other Gas E11 Other Energy E12 ESL-IE-00-04-17 Proceedings from the Twenty-second National..., electrical consumption, demand and fees were tracked separately. The remaining data include only one energy stream (e.g., natural gas) in each code [6]. Table 1. Energy Streams STREAM CODE Electrical Consumption EC Electrical Demand ED Other...

  10. Enhancement of spin polarization via Fermi level tuning in Co{sub 2}MnSn{sub 1?x}Sb{sub x} (x = 0, 0.25. 0.5, 0.75, 1) Heusler alloys

    SciTech Connect (OSTI)

    Singh, Mukhtiyar Thakur, Jyoti; Kashyap, Manish K.; Saini, Hardev S.

    2014-04-24

    Full potential approach has been employed to tune Fermi level in Co{sub 2}MnSn{sub 1?x}Sb{sub x} (x = 0, 0.25, 0.5, 0.75, 1) Heulser alloys for enhancement of spin polarization and finding signature of half metallicity. Present density functional theory (DFT) based calculation indicates that stoichoimetric Heusler alloy, Co{sub 2}MnSn is not a half-metallic ferromagnet but the doping of Sb in it results in the shifting of E{sup F} in well-defined energy gap which leads the 100% spin polarization in the resultant alloys. The magnetism in present alloys is governed by localized moment on Mn atom mainly. The tuning of half-metallicity using doping can be proved as an ideal technique to search the new materials which can accomplish the need of spintronics.

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

    SciTech Connect (OSTI)

    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

    2013-08-15

    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.

  12. Non-thermal electron acceleration in low Mach number collisionless shocks. II. Firehose-mediated Fermi acceleration and its dependence on pre-shock conditions

    SciTech Connect (OSTI)

    Guo, Xinyi; Narayan, Ramesh; Sironi, Lorenzo

    2014-12-10

    Electron acceleration to non-thermal energies is known to occur in low Mach number (M{sub s} ? 5) shocks in galaxy clusters and solar flares, but the electron acceleration mechanism remains poorly understood. Using two-dimensional (2D) particle-in-cell (PIC) plasma simulations, we showed in Paper I that electrons are efficiently accelerated in low Mach number (M{sub s} = 3) quasi-perpendicular shocks via a Fermi-like process. The electrons bounce between the upstream region and the shock front, with each reflection at the shock resulting in energy gain via shock drift acceleration. The upstream scattering is provided by oblique magnetic waves that are self-generated by the electrons escaping ahead of the shock. In the present work, we employ additional 2D PIC simulations to address the nature of the upstream oblique waves. We find that the waves are generated by the shock-reflected electrons via the firehose instability, which is driven by an anisotropy in the electron velocity distribution. We systematically explore how the efficiency of wave generation and of electron acceleration depend on the magnetic field obliquity, the flow magnetization (or equivalently, the plasma beta), and the upstream electron temperature. We find that the mechanism works for shocks with high plasma beta (? 20) at nearly all magnetic field obliquities, and for electron temperatures in the range relevant for galaxy clusters. Our findings offer a natural solution to the conflict between the bright radio synchrotron emission observed from the outskirts of galaxy clusters and the low electron acceleration efficiency usually expected in low Mach number shocks.

  13. On the contribution of plasminos to the shear viscosity of a hot and dense Yukawa-Fermi gas

    E-Print Network [OSTI]

    N. Sadooghi; F. Taghinavaz

    2015-04-16

    Using the standard Green-Kubo formalism, we determine the shear viscosity $\\eta$ of a hot and dense Yukawa-Fermi gas. In particular, we study the effect of particle and plasmino excitations on thermal properties of the fermionic part of the shear viscosity, and explore the effects of thermal corrections to particle masses on bosonic and fermionic shear viscosities, $\\eta_b$ and $\\eta_f$. It turns out that the effects of plasminos on $\\eta_f$ become negligible with increasing (decreasing) temperature (chemical potential).

  14. Direct observation of Fermi surface in YBa sub 2 Cu sub 3 O sub 7 minus. delta

    SciTech Connect (OSTI)

    Haghighi, H.; Kaiser, J.H.; Rayner, S.; West, R.N.; Liu, J.Z.; Shelton, R.; Howell, R.H.; Solal, F.; Fluss, M.J. University of California at Davis, Davis, California 95616 Lawrence Livermore National Laboratory, Livermore, California 94550 )

    1991-07-15

    We have performed a high-precision measurement (5{times}10{sup 8} coincidence counts) of the basal-plane electron-positron momentum density in well oxygenated, twin-free, single crystals of YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}}. The raw, processed, and {bold K}-space reduced spectra unambiguously show a clear image of a major Fermi surface sheet. The form and profile of that image are in substantial quantitative agreement with theoretical predictions of a {Gamma}-{ital X} electron ridge section associated with states in the CuO chains.

  15. Deriving the quark condensate within a finite Fermi system from the generating functional of chiral perturbation theory

    E-Print Network [OSTI]

    Mariana Kirchbach; Andreas Wirzba

    1996-11-01

    The generating functional of heavy baryon chiral perturbation theory at order O(Q^2) in the mean field approximation (with a pseudoscalar source coupling which is consistent with the PCAC-Ward identities on the current quark level) has been exploited to derive Migdal's in--medium pion propagator. It is shown that the prediction for the density dependence of the quark condensate obtained on the composite hadron level by embedding PCAC within the framework of Migdal's approach to finite Fermi systems is identical to that resulting from QCD.

  16. Deriving the quark condensate within a finite Fermi system from the generating functional of chiral perturbation theory

    E-Print Network [OSTI]

    Kirchbach, M; Kirchbach, Mariana; Wirzba, Andreas

    1996-01-01

    The generating functional of heavy baryon chiral perturbation theory at order {\\cal O}(Q^2) in the mean field approximation (with a pseudoscalar source coupling which is consistent with the PCAC-Ward identities on the current quark level) has been exploited to derive Migdal's in--medium pion propagator. It is shown that the prediction for the density dependence of the quark condensate obtained on the composite hadron level by embedding PCAC within the framework of Migdal's approach to finite Fermi systems is identical to that resulting from QCD.

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

    SciTech Connect (OSTI)

    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)

    2014-01-13

    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.

  18. PHYSICAL REVIEW B 83, 104511 (2011) Superconducting energy gap in MgCNi3 single crystals: Point-contact spectroscopy

    E-Print Network [OSTI]

    Boyer, Edmond

    2011-01-01

    PHYSICAL REVIEW B 83, 104511 (2011) Superconducting energy gap in MgCNi3 single crystals: Point Center for Superconductivity, Sogang University, Seoul 100-611, Republic of Korea (Received 14 December that a superconducting energy gap is fully open on the whole Fermi surface, in agreement with our previous magnetic

  19. Constancy of energy partition in central heavy-ion reactions at intermediate energies

    E-Print Network [OSTI]

    Z. Basrak; Ph. Eudes; M. Zori?; F. Sébille

    2012-09-10

    Semiclassical transport simulation of nucleus-nucleus collisions for the range of incident energy from about the Fermi energy up to a few hundred MeV per nucleon evidences that the maximal excitation energy put into a nuclear system during the early compact stage of heavy-ion reaction is a constant fraction of the center-of-mass available energy of the system. Analysis of experimental data without presuming reaction mechanism dominating the collision process on the best corroborate the found constancy of energy partition in central heavy-ion reactions.

  20. Fermi level control of compensating point defects during metalorganic chemical vapor deposition growth of Si-doped AlGaN

    SciTech Connect (OSTI)

    Bryan, Z; Bryan, I; Gaddy, BE; Reddy, P; Hussey, L; Bobea, M; Guo, W; Hoffmann, M; Kirste, R; Tweedie, J; Gerhold, M; Irving, DL; Sitar, Z; Collazo, R

    2014-12-01

    A Fermi-level control scheme for point defect management using above-bandgap UV illumination during growth is presented. We propose an extension to the analogy between the Fermi level and the electrochemical potential such that the electrochemical potential of a charged defect in a material with steady-state populations of free charge carriers may be expressed in terms of the quasi-Fermi levels. A series of highly Si-doped Al0.65Ga0.35N films grown by metalorganic chemical vapor deposition with and without UV illumination showed that samples grown under UV illumination had increased free carrier concentration, free carrier mobility, and reduced midgap photoluminescence all indicating a reduction in compensating point defects. (c) 2014 AIP Publishing LLC.

  1. Energy and Demand Savings from Implementation Costs in Industrial Facilities 

    E-Print Network [OSTI]

    Razinha, J. A.; Heffington, W. M.

    2000-01-01

    .g., natural gas) in each code [6]. Table 1. Energy Streams STREAM CODE Electrical Consumption EC Electrical Demand ED Other Electrical Fees EF Electricity E1 Natural Gas E2 L.P.G. E3 #1 Fuel Oil E4 #2 Fuel Oil E5 #4 Fuel Oil E6 #6 Fuel... Oil E7 Coal E8 Wood E9 Paper E10 Other Gas E11 Other Energy E12 3 The current database contains records of nearly 9000 assessment visits and almost 64,000 ARs. It is publicly accessible via the Internet [4], and is easily sorted...

  2. Scaling of the known exact explicit forms of the non-interacting kinetic-energy density functional

    E-Print Network [OSTI]

    Lázaro Calderín

    2014-10-15

    It has been previously proven that the Kohn-Sham kinetic energy functional scales homogeneusly under generalized coordinate scaling, in a way that is obeyed by the von Weiz\\"acker functional, but seems to be in contradiction with the scaling of the Thomas-Fermi functional. A very puzzling situation, taking in to account that the von Weiz\\"acker and Thomas-Fermi functionals are exact cases of the Kohn-Sham kinetic energy functional for two electron systems, and the non-interacting electron gas, respectively. The apparent contradiction is resolved in this paper.

  3. Direct, experimental evidence of the Fermi surface in YBa sub 2 Cu sub 3 O sub 7-x

    SciTech Connect (OSTI)

    Haghighi, H.; Kaiser, J.H.; Rayner, S.L.; West, R.N. ); Liu, J.Z.; Shelton, R. ); Howell, R.H.; Sterne, P.A.; Solal, F.; Fluss, M.J. )

    1991-04-29

    We report new measurements of the electron-positron momentum spectra of YBa{sub 2}Cu{sub 3}O{sub 7-x} performed with ultra-high statistical precision. These data differ from previous results in two significant respects: They show the D{sub 2} symmetry appropriate for untwinned crystals and, more importantly, they show unmistakable, statistically significant, discontinuities that are evidence of a major Fermi surface section. These results provide a partial answer to a question of special significance to the study of high temperature superconductors i.e. the distribution of the electrons in the material, the electronic structure. Special consideration has been given both experimentally and theoretically to the existence and shape of a Fermi surface in the materials and to the superconducting gap. There are only three experimental techniques that can provide details of the electronic structure at useful resolutions. They are angular correlation of positron annihilation radiation, ACAR, angle resolved photo emission, PE, and de Haas van Alphen measurements. 11 refs., 4 figs.

  4. JOURNAL DE PHYSIQUE Colloque C5, supplkment au no 5, Tome 40, Mai 1979,page C5-71 The de Haas-van Alphen effect and the Fermi surfaces of rare earth metals

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    -van Alphen effect and the Fermi surfaces of rare earth metals R. C . Young Department of Physics, University (some transition metals, rare earths, inter- metallic compounds) it is difficult to achieve an & of even been achieved for Fermi surface investigation of rare earth metals. Substantial dHvA results have now

  5. Bohm's Quantum Potential as an Internal Energy

    E-Print Network [OSTI]

    Glen Dennis; Maurice de Gosson; Basil Hiley

    2014-12-15

    We pursue our discussion of Fermi's surface initiated in Dennis, de Gosson and Hiley and show that Bohm's quantum potential can be viewed as an internal energy of a quantum system. This gives further insight into the role it played by the quantum potential in stationary states. It also allows us to provide a physically motivated derivation of Schr\\"odinger's equation for a particle in an external potential.

  6. Fermi-LAT and Suzaku Observations of the Radio Galaxy Centaurus...

    Office of Scientific and Technical Information (OSTI)

    as a public service. Visit OSTI to utilize additional information resources in energy science and technology. A paper copy of this document is also available for sale to...

  7. Impacts of the Nuclear Symmetry Energy on Neutron Star Crusts

    E-Print Network [OSTI]

    Bao, Shishao

    2015-01-01

    Using the relativistic mean-field theory, we adopt two different methods, namely, the coexisting phase method and the self-consistent Thomas-Fermi approximation, to study the impacts of the nuclear symmetry energy on properties of neutron star crusts within a wide range of densities. It is found that the nuclear symmetry energy and its density slope play an important role in determining the pasta phases and the crust-core transition.

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

    E-Print Network [OSTI]

    Morselli, Aldo

    but there are competing astrophysical sources, such as pulsars, that can give a strong flux of primary positrons Gamma-ray Space Telescope, has detected the largest amount of gamma rays, in the 20MeV 300GeV energy and electrons (see [10], [11], [12], [13] and references therein). At energies between 100 GeV and 1 Te

  9. Electrostatic Field and Partial Fermi Level Pinning at the Pentacene-SiO2 Interface Liwei Chen,, R. Ludeke, Xiaodong Cui, Alejandro G. Schrott, Cherie R. Kagan, and

    E-Print Network [OSTI]

    band maximum and electron traps at 0.69 eV below the conduction band minimum were observed. To further of pentacene thin films. When a thin oxide layer is used on the substrate, electron tunneling through-thin oxides, tunneling across the oxides allows Fermi level equilibration with pentacene associated states

  10. Do the Fermi Gamma-Ray Burst Monitor and Swift Burst Alert Telescope see the Same Short Gamma-Ray Bursts?

    E-Print Network [OSTI]

    Burns, Eric; Zhang, Bin-Bin; Lien, Amy; Briggs, Michael S; Goldstein, Adam; Pelassa, Veronique; Troja, Eleonora

    2015-01-01

    Compact binary system mergers are expected to generate gravitational radiation detectable by ground-based interferometers. A subset of these, the merger of a neutron star with another neutron star or a black hole, are also the most popular model for the production of short gamma-ray bursts (GRBs). The Swift Burst Alert Telescope (BAT) and the Fermi Gamma-ray Burst Monitor (GBM) trigger on short GRBs (SGRBs) at rates that reflect their relative sky exposures, with the BAT detecting 10 per year compared to about 45 for GBM. We examine the SGRB populations detected by Swift BAT and Fermi GBM. We find that the Swift BAT triggers on weaker SGRBs than Fermi GBM, providing they occur close to the center of the BAT field-of-view, and that the Fermi GBM SGRB detection threshold remains flatter across its field-of-view. Overall, these effects combine to give the instruments the same average sensitivity, and account for the SGRBs that trigger one instrument but not the other. We do not find any evidence that the BAT and...

  11. FERMI-LAT OBSERVATIONS OF SUPERNOVA REMNANTS INTERACTING WITH MOLECULAR CLOUDS: W41, MSH 17-39, AND G337.7-0.1

    E-Print Network [OSTI]

    Castro, Daniel

    We report the detection of ?-ray emission coincident with three supernova remnants (SNRs) using data from the Large Area Telescope on board the Fermi Gamma-ray Space Telescope. W41, G337.7-0.1, and MSH 17-39 are SNRs known ...

  12. 2013 Annual Planning Summary for the FERMI Site Office | Department of

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of Natural GasAdjustmentsShirleyEnergyTher i n c i p a l De p u t y A s s i sEnergy It is the intentEnergy 3 and

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

    Office of Scientific and Technical Information (OSTI)

    cmsup -2 ssup -1. The photon spectrum is well-described by an exponentially cut-off power law of the form dFdE kEsup -Gammaesup (-EEsub c) where the energy E is...

  14. Pd/Cu Site Interchange and Non-Fermi-Liquid Behavior in UCu{sub 4}Pd

    SciTech Connect (OSTI)

    Booth, C.H.; MacLaughlin, D.E.; Heffner, R.H.; Kwei, G.H. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)] [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); MacLaughlin, D.E. [Department of Physics, University of California, Riverside, California 92521 (United States)] [Department of Physics, University of California, Riverside, California 92521 (United States); Chau, R.; Maple, M.B. [Department of Physics, University of California, San Diego, California 92093 (United States)] [Department of Physics, University of California, San Diego, California 92093 (United States)

    1998-11-01

    X-ray-absorption fine-structure measurements of the local structure in UCu{sub 4}Pd are described which indicate a probable lattice-disorder origin for non-Fermi-liquid behavior in this material. Short Pd-Cu distances are observed, consistent with (24{plus_minus}3){percent} of the Pd atoms occupying nominally Cu sites. A {open_quotes}Kondo disorder{close_quotes} model, based on the effect on the local Kondo temperature T{sub K} of this interchange and some additional bond-length disorder, agrees quantitatively with previous experimental susceptibility data, and therefore also with specific heat and magnetic resonance experiments. {copyright} {ital 1998} {ital The American Physical Society }

  15. Compton scattering in terrestrial gamma-ray flashes detected with the Fermi gamma-ray burst monitor

    E-Print Network [OSTI]

    Fitzpatrick, Gerard; McBreen, Sheila; Briggs, Michael S; Foley, Suzanne; Tierney, David; Chaplin, Vandiver L; Connaughton, Valerie; Stanbro, Matthew; Xiong, Shaolin; Dwyer, Joseph; Fishman, Gerald J; Roberts, Oliver J; von Kienlin, Andreas

    2015-01-01

    Terrestrial gamma-ray flashes (TGFs) are short intense flashes of gamma rays associated with lightning activity in thunderstorms. Using Monte Carlo simulations of the relativistic runaway electron avalanche (RREA) process, theoretical predictions for the temporal and spectral evolution of TGFs are compared to observations made with the Gamma-ray Burst Monitor (GBM) on board the Fermi Gamma-ray Space Telescope. Assuming a single source altitude of 15 km, a comparison of simulations to data is performed for a range of empirically chosen source electron variation time scales. The data exhibit a clear softening with increased source distance, in qualitative agreement with theoretical predictions. The simulated spectra follow this trend in the data, but tend to underestimate the observed hardness. Such a discrepancy may imply that the basic RREA model is not sufficient. Alternatively, a TGF beam that is tilted with respect to the zenith could produce an evolution with source distance that is compatible with the da...

  16. Schottky barrier height reduction for holes by Fermi level depinning using metal/nickel oxide/silicon contacts

    SciTech Connect (OSTI)

    Islam, Raisul, E-mail: raisul@stanford.edu; Shine, Gautam; Saraswat, Krishna C. [Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States)

    2014-11-03

    We report the experimental demonstration of Fermi level depinning using nickel oxide (NiO) as the insulator material in metal-insulator-semiconductor (M-I-S) contacts. Using this contact, we show less than 0.1?eV barrier height for holes in platinum/NiO/silicon (Pt/NiO/p-Si) contact. Overall, the pinning factor was improved from 0.08 (metal/Si) to 0.26 (metal/NiO/Si). The experimental results show good agreement with that obtained from theoretical calculation. NiO offers high conduction band offset and low valence band offset with Si. By reducing Schottky barrier height, this contact can be used as a carrier selective contact allowing hole transport but blocking electron transport, which is important for high efficiency in photonic applications such as photovoltaics and optical detectors.

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

    E-Print Network [OSTI]

    Kohley, Zachary Wayne

    2011-10-21

    The Equation of State (EoS) of asymmetric nuclear matter has been explored through the study of mid-rapidity fragment dynamics from the 35 MeV/u $^{70}$Zn $^{70}$Zn, $^{64}$Zn $^{64}$Zn, and $^{64}$Ni $^{64}$Ni systems. ...

  18. Suzaku X-ray Observations of the Fermi Bubbles: Northernmost Cap and Southeast Claw Discovered with MAXI-SSC

    E-Print Network [OSTI]

    M. Tahara; J. Kataoka; Y. Takeuchi; T. Totani; Y. Sofue; J. S. Hiraga; H. Tsunemi; Y. Inoue; M. Kimura; C. C. Cheung; S. Nakashima

    2015-02-04

    We report on Suzaku observations of large-scale X-ray structures possibly related with the Fermi Bubbles obtained in 2013 with a total duration of ~ 80 ks. The observed regions were the: (i) northern cap (N-cap; l ~ 0 deg, 45 deg map recently provided by MAXI-SSC and (ii) southeast claw (SE-claw; l ~ 10 deg, -20 deg map and MAXI-SSC Low-band (0.7-1.7 keV) map. In each region, we detected diffuse X-ray emissions which are represented by a three component plasma model consisting of an unabsorbed thermal component (kT ~ 0.1 keV) from the Local Bubble, absorbed kT = 0.30+/-0.05 keV emission representing the Galactic Halo, and a power-law component due to the isotropic cosmic X-ray background radiation. The emission measure of the GH component in the SE-claw shows an excess by a factor of ~ 2.5 over the surrounding emission at 2 deg away. We also found a broad excess in the 1.7-4.0 keV count rates across the N-cap after compiling other archival data from Suzaku and Swift. The spectral stacking analysis of the N-cap data indicates the presence of another thermal component with kT = 0.70 (+0.22,-0.11) keV. The temperature of kT ~ 0.3 keV of the Galactic Halo is higher than the ubiquitous value of kT ~ 0.2 keV near the Fermi Bubbles, and can be even higher (~ 0.7 keV). We discuss our findings in the context of bubble-halo interaction.

  19. Energy density matrix formalism for interacting quantum systems: a quantum Monte Carlo study

    SciTech Connect (OSTI)

    Krogel, Jaron T; Kim, Jeongnim; Reboredo, Fernando A

    2014-01-01

    We develop an energy density matrix that parallels the one-body reduced density matrix (1RDM) for many-body quantum systems. Just as the density matrix gives access to the number density and occupation numbers, the energy density matrix yields the energy density and orbital occupation energies. The eigenvectors of the matrix provide a natural orbital partitioning of the energy density while the eigenvalues comprise a single particle energy spectrum obeying a total energy sum rule. For mean-field systems the energy density matrix recovers the exact spectrum. When correlation becomes important, the occupation energies resemble quasiparticle energies in some respects. We explore the occupation energy spectrum for the finite 3D homogeneous electron gas in the metallic regime and an isolated oxygen atom with ground state quantum Monte Carlo techniques imple- mented in the QMCPACK simulation code. The occupation energy spectrum for the homogeneous electron gas can be described by an effective mass below the Fermi level. Above the Fermi level evanescent behavior in the occupation energies is observed in similar fashion to the occupation numbers of the 1RDM. A direct comparison with total energy differences demonstrates a quantita- tive connection between the occupation energies and electron addition and removal energies for the electron gas. For the oxygen atom, the association between the ground state occupation energies and particle addition and removal energies becomes only qualitative. The energy density matrix provides a new avenue for describing energetics with quantum Monte Carlo methods which have traditionally been limited to total energies.

  20. Parameter constraints in a near-equipartition model with multi-frequency \\emph{NuSTAR}, \\emph{Swift} and \\emph{Fermi-LAT} data from 3C 279

    E-Print Network [OSTI]

    Yan, Dahai; Zhang, Shuang-Nan

    2015-01-01

    Precise spectra of 3C 279 in the 0.5-70 keV range, obtained during two epochs of \\emph{Swift} and \\emph{NuSTAR} observations, are analyzed using a near-equipartition model. We apply a one-zone leptonic model with a three-parameter log-parabola electron energy distribution (EED) to fit the \\emph{Swift} and \\emph{NuSTAR} X-ray data, as well as simultaneous optical and \\emph{Fermi}-LAT $\\gamma$-ray data. The Markov Chain Monte Carlo (MCMC) technique is used to search the high-dimensional parameter space and evaluate the uncertainties on model parameters. We show that the two spectra can be successfully fit in near-equipartition conditions, defined by the ratio of the energy density of relativistic electrons to magnetic field $\\zeta_{\\rm e}$ being close to unity. In both spectra, the observed X-rays are dominated by synchrotron-self Compton photons, and the observed $\\gamma$ rays are dominated by Compton scattering of external infrared photons from a surrounding dusty torus. Model parameters are well constrained....

  1. A study of nuclear stopping in central symmetric nuclear collisions at intermediate energies

    E-Print Network [OSTI]

    C. Escano-Rodriguez; D. Durand; A. Chbihi; J. D. Frankland; the INDRA Collaboration

    2005-03-14

    Nuclear stopping has been investigated in central symmetric nuclear collisions at intermediate energies. Firstly, it is found that the isotropy ratio, Riso, reaches a minimum near the Fermi energy and saturates or slowly increases depending on the mass of the system as the beam energy increases. An approximate scaling based on the size of the system is found above the Fermi energy suggesting the increasing role of in-medium nucleon-nucleon collisions. Secondly, the charge density distributions in velocity space, dZ/dvk and dZ/dv?, reveal a strong memory of the entrance channel and, as such, a sizeable nuclear transparency in the intermediate energy range. Lastly, it is shown that the width of the transverse velocity distribution is proportional to the beam velocity.

  2. Observation of an electron band above the Fermi level in FeTe{sub 0.55}Se{sub 0.45} from in-situ surface doping

    SciTech Connect (OSTI)

    Zhang, P.; Ma, J.; Qian, T.; Richard, P. Ding, H.; Xu, N.; Xu, Y.-M.; Fedorov, A. V.; Denlinger, J. D.; Gu, G. D.

    2014-10-27

    We used in-situ potassium (K) evaporation to dope the surface of the iron-based superconductor FeTe{sub 0.55}Se{sub 0.45}. The systematic study of the bands near the Fermi level confirms that electrons are doped into the system, allowing us to tune the Fermi level of this material and to access otherwise unoccupied electronic states. In particular, we observe an electron band located above the Fermi level before doping that shares similarities with a small three-dimensional pocket observed in the cousin, heavily electron-doped KFe{sub 2?x}Se{sub 2} compound.

  3. Harnessing the Energy of the Stars | Department of Energy

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of Natural GasAdjustmentsShirleyEnergy A plug-inPPLforLDRD Report11, SolarMatFermiGuidoEnvironmentalA view of a

  4. Have You Seen Our Energy 101 Videos? | Department of Energy

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of Natural GasAdjustmentsShirleyEnergy A plug-inPPLforLDRD Report11, SolarMatFermiGuidoEnvironmentalA view of aofOver

  5. Threshold singularities in a Fermi gas with attractive potential in one dimension

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

    Schlottmann, P.; Zvyagin, A. A.

    2015-01-15

    We consider the one-dimensional gas of fermions with spin S interacting via an attractive ?-function potential using the Bethe Ansatz solution. In zero magnetic field the atoms form bound states of N=2S + 1 fermions, i.e. generalized Cooper states with each atom having a different spin component. For low energy excitations the system is a Luttinger liquid and is properly described by a conformal field theory with conformal charge c=1. The linear dispersion of a Luttinger liquid is asymptotically exact in the low-energy limit where the band curvature terms in the dispersion are irrelevant. For higher energy excitations, however, themore »spectral function displays deviations in the neighborhood of the single-particle (hole) energy, which can be described by an effective X-ray edge type model. Using the Bethe Ansatz solution we obtain expressions for the critical exponents for the single-particle (hole) Green’s function. This model can be relevant in the context of ultracold atoms with effective total spin S confined to an elongated optical trap.« less

  6. Groundwater Database | Department of Energy

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of Natural GasAdjustmentsShirleyEnergy A plug-inPPLforLDRD Report11, SolarMatFermi National Accelerator Laboratoryone of

  7. Headquarters Awards | Department of Energy

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of Natural GasAdjustmentsShirleyEnergy A plug-inPPLforLDRD Report11, SolarMatFermiGuidoEnvironmentalA viewWhat does08

  8. Assessing regional evapotranspiration and water balance across a Mediterranean montane climate gradient

    E-Print Network [OSTI]

    Anderson, Ray G.; Jin, Yufang; Goulden, Michael L.

    2012-01-01

    EF maps, and multiplied EF by net radiation and groundb) Map of annually averaged available energy (net radiation-radiation (Rn), ground heat ?ux (G) and available energy (AE) used to calculate ET from EF maps.

  9. The idea of the neutrino was put forward in 1930 by Wolfgang Pauli in a desperate attempt to preserve energy

    E-Print Network [OSTI]

    Knowles, David William

    with the idea of an atomic bomb as the source, Reines settled on a nuclear reactor and discovered the neutrino to preserve energy conservation in nuclear beta decay. Soon Enrico Fermi ex- ploited the idea to create a theory of the weak interactions that laid the foundation for the now-standard model of par- ticle physics

  10. Fermi Research Alliance: PPO Plan Coverage Period: 01/01/2015 12/31/2015 Summary of Benefits and Coverage: What this Plan Covers & What it Costs Coverage for: ALL | Plan Type: PPO

    E-Print Network [OSTI]

    Fermilab Experiment E831

    1 of 8 Fermi Research Alliance: PPO Plan Coverage Period: 01/01/2015 ­ 12/31/2015 Summary Research Alliance: PPO Plan Coverage Period: 01/01/2015 ­ 12/31/2015 Summary of Benefits and Coverage: What

  11. Effects of short-range correlation reduced kinetic symmetry energy in heavy-ion collisions at intermediate energies

    E-Print Network [OSTI]

    Bao-An Li; Wen-Jun Guo; Zhaozhong Shi

    2015-03-20

    Besides earlier predictions based on both phenomenological models and modern microscopic many-body theories, circumstantial evidence was recently found for a reduced kinetic symmetry energy of isospin-asymmetric nucleonic matter compared to the free Fermi gas model prediction due to the short-range correlation of high-momentum neutron-proton pairs. While keeping the total symmetry energy near the saturation density of nuclear matter consistent with existing experimental constraints, we examine the correspondingly enhanced role of the isospin degree of freedom in heavy-ion collisions at intermediate energies due to the reduced (enhanced) kinetic (potential) symmetry energy. Important observable consequences are investigated.

  12. Guiding Documents and Links | Department of Energy

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of Natural GasAdjustmentsShirleyEnergy A plug-inPPLforLDRD Report11, SolarMatFermi NationalannualofandEnergyFederal

  13. The electron-positron momentum density and Fermi surface of YBa{sub 2}Cu{sub 3}O{sub 7-x}

    SciTech Connect (OSTI)

    Haghighi, H.; Kaiser, J.H.; Rayner, S.; West, R.N.; Liu, J.Z.; Shelton, R.; Howell, R.H.; Solal, F.; Sterne, P.A.; Fluss, M.J.

    1991-10-11

    The search for evidence of Fermi surface in the cuprate high temperature superconductors has provided the greatest challenge for the 2D ACAR technique thus far in its relatively short history. Much of the effort in both theory and experiment has focused on the Yttrium compound where the small size of samples, twinning and structural oxygen defects have made the experiments difficult, complicated the interpretation of results and led to some confusion. With the advent of good twin-free crystals that confusion has now been resolved. In this paper we shall briefly review the earlier experiments on twinned crystals and then describe in more detail, and in the context of the contemporary bandstructure theory, our recent clear resolution of a major Fermi surface section in untwinned crystals of YBa{sub 2}Cu{sub 3}O{sub 7-x}.

  14. arXiv:submit/0490655[astro-ph.HE]8Jun2012 2011 Fermi & Jansky: Our Evolving Understanding of AGN, St Michaels, MD, Nov. 10-12 1 Imaging at Both Ends of the Spectrum: the Long Wavelength Array and Fermi

    E-Print Network [OSTI]

    Taylor, Greg

    and Fermi G.B. Taylor on behalf of the LWA Collaboration University of New Mexico The Long Wavelength Array lines, solar and Jupiter bursts, investigations into the "dark ages" using redshifted hydrogen Research Laboratory (NRL), New Mex- ico Tech (NMT), University of New Mexico (UNM), UTB, and Virginia Tech

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

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of Natural GasAdjustmentsShirleyEnergy A plug-inPPLforLDRD Report11, SolarMat 4" | DepartmentJuneDecember 2015

  16. President Obama Names Scientists Bard and Sessler as Enrico Fermi Award

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMass mapSpeedingProgram Guidelines ThisHENPDepartment's Clean Energy Grand Challenges

  17. President Obama Welcomes 2013 Fermi Award Winners to the White House |

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMass mapSpeedingProgram Guidelines ThisHENPDepartment's Clean Energy Grand

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

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTech ConnectSpeedingConnect Pulse energy measurement at the SXR instrument

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

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTech ConnectSpeedingConnect Pulse energy measurement at the SXR instrument(Journal

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

    Office of Science (SC) Website

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power AdministrationRobust,Field-effectWorkingLosThe 26thI D- 6 0 4ContractFacilities High Energy PhysicsU.S.Home

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

    E-Print Network [OSTI]

    Burch, Robert Harry

    1988-01-01

    LIST OF FIGURES . CHAPTER 1V Vl V 1 1 V111 I INTRODUCTION II THEORY III EXPERIMENTAL METHODS IV ANALYSIS V CONCLUSION REFERENCES . 15 47 53 VITA 56 vis LIST OF TABLES Table 1 As Spectra Fitting Parameters 2 Br and Al Spectra Fitting... (Siyl) at the level of quantum corrections. The Conserved Vector Current (CVC) theory predicts a constant Ft-value for all superallowed Fermi transitions, independent of the nucleus (Blin-Stoyle, 1973). If' radiative and Coulomb corrections...

  2. Women @ Energy: Rhonda Merchut | Department of Energy

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

    University of Illinois at Chicago, where she earned a bachelor of science degree in architecture. Rhonda Merchut is an engineer at Fermi National Accelerator Laboratory (Fermilab)....

  3. Fits to the Fermi-LAT GeV excess with RH sneutrino dark matter: implications for direct and indirect dark matter searches and the LHC

    E-Print Network [OSTI]

    Cerdeno, D G; Robles, S

    2015-01-01

    We show that the right-handed (RH) sneutrino in the NMSSM can account for the observed excess in the Fermi-LAT spectrum of gamma rays from the Galactic Centre, while fulfilling all the current experimental constraints from the LHC as well as from direct and indirect dark matter searches. We have explored the parameter space of this scenario, computed the gamma ray spectrum for each phenomenologically viable solution and then performed a chi^2 fit to the excess. Unlike previous studies based on model independent interpretations, we have taken into account the full annihilation spectrum, without assuming pure annihilation channels. Furthermore, we have incorporated limits from direct detection experiments, LHC bounds and also the constraints from Fermi-LAT on dwarf spheroidal galaxies (dSphs) and gamma ray spectral lines. In addition, we have estimated the effect of the most recent Fermi-LAT reprocessed data (Pass~8). In general, we obtain good fits to the GCE when the RH sneutrino annihilates mainly into pairs...

  4. Energy

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTechtail.Theory ofDid you not find what youSummerEmployment Opportunities Thank you forEnergy

  5. ENERGY

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE:FinancingPetroleum Based|DepartmentStatementof EnergyQuality'Lean' System09 EMABMay 200810 U.S.

  6. Exact solution for low energy quantum anharmonic vibrations in a long polymer chain

    E-Print Network [OSTI]

    Alexander L. Burin

    2015-11-10

    We propose the algorithm for determining vibrational quantum eigenstates of periodic linear chain of atoms coupled by harmonic and third order anharmonic interactions (Fermi-Ulam-Pasta $\\alpha$ problem) in the long wavelength limit within the resonant approach. Eigenstates can be encoded by the sequence of integer numbers determining their energies and wavefunctions. Using these eigenstates we described a single phonon state time evolution showing coherent oscillations. The applications of theory to vibrational energy transport and quantum informatics are discussed.

  7. Separation of particles leading to decay and unlimited growth of energy in a driven stadium-like billiard

    E-Print Network [OSTI]

    André L. P. Livorati; Matheus S. Palmero; Carl P. Dettmann; Iberê L. Caldas; Edson D. Leonel

    2015-07-01

    A competition between decay and growth of energy in a time-dependent stadium billiard is discussed giving emphasis in the decay of energy mechanism. A critical resonance velocity is identified for causing of separation between ensembles of high and low energy and a statistical investigation is made using ensembles of initial conditions both above and below the resonance velocity. For high initial velocity, Fermi acceleration is inherent in the system. However for low initial velocity, the resonance allies with stickiness hold the particles in a regular or quasi-regular regime near the fixed points, preventing them from exhibiting Fermi acceleration. Also, a transport analysis along the velocity axis is discussed to quantify the competition of growth and decay of energy and making use distributions of histograms of frequency, and we set that the causes of the decay of energy are due to the capture of the orbits by the resonant fixed points.

  8. Detailed Report of the MuLan Measurement of the Positive Muon Lifetime and Determination of the Fermi Constant

    E-Print Network [OSTI]

    V. Tishchenko; S. Battu; R. M. Carey; D. B. Chitwood; J. Crnkovic; P. T. Debevec; S. Dhamija; W. Earle; A. Gafarov; K. Giovanetti; T. P. Gorringe; F. E. Gray; Z. Hartwig; D. W. Hertzog; B. Johnson; P. Kammel; B. Kiburg; S. Kizilgul; J. Kunkle; B. Lauss; I. Logashenko; K. R. Lynch; R. McNabb; J. P. Miller; F. Mulhauser; C. J. G. Onderwater; Q. Peng; J. Phillips; S. Rath; B. L. Roberts; D. M. Webber; P. Winter; B. Wolfe

    2012-11-05

    We present a detailed report of the method, setup, analysis and results of a precision measurement of the positive muon lifetime. The experiment was conducted at the Paul Scherrer Institute using a time-structured, nearly 100%-polarized, surface muon beam and a segmented, fast-timing, plastic scintillator array. The measurement employed two target arrangements; a magnetized ferromagnetic target with a ~4 kG internal magnetic field and a crystal quartz target in a 130 G external magnetic field. Approximately 1.6 x 10^{12} positrons were accumulated and together the data yield a muon lifetime of tau_{mu}(MuLan) = 2196980.3(2.2) ps (1.0 ppm), thirty times more precise than previous generations of lifetime experiments. The lifetime measurement yields the most accurate value of the Fermi constant G_F (MuLan) = 1.1663787(6) x 10^{-5} GeV^{-2} (0.5 ppm). It also enables new precision studies of weak interactions via lifetime measurements of muonic atoms.

  9. A tale of tails. Dark matter interpretations of the Fermi GeV excess in light of background model systematics

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

    Calore, Francesca; Cholis, Ilias; McCabe, Christopher; Weniger, Christoph

    2015-03-10

    Several groups have identified an extended excess of gamma rays over the modeled foreground and background emissions towards the Galactic center (GC) based on observations with the Fermi Large Area Telescope. This excess emission is compatible in morphology and spectrum with a telltale sign from dark matter (DM) annihilation. Here, we present a critical reassessment of DM interpretations of the GC signal in light of the foreground and background uncertainties that some of us recently outlaid in Calore et al. (2014). We find that a much larger number of DM models fits the gamma-ray data than previously noted. In particular:more »(1) In the case of DM annihilation into b¯b, we find that even large DM masses up to m??74 GeV are allowed at p-value >0.05. (2) Surprisingly, annihilation into nonrelativistic hh gives a good fit to the data. (3) The inverse Compton emission from ?+?– with m? ~ 60–70 GeV can also account for the excess at higher latitudes, |b|>2°, both in its spectrum and morphology. We also present novel constraints on a large number of mixed annihilation channels, including cascade annihilation involving hidden sector mediators. In conclusion, we show that the current limits from dwarf spheroidal observations are not in tension with a DM interpretation when uncertainties on the DM halo profile are accounted for.« less

  10. FIVE NEW MILLISECOND PULSARS FROM A RADIO SURVEY OF 14 UNIDENTIFIED FERMI-LAT GAMMA-RAY SOURCES

    SciTech Connect (OSTI)

    Kerr, M.; Camilo, F.; Johnson, T. J.; Ferrara, E. C.; Harding, A. K.; Guillemot, L.; Kramer, M.; Hessels, J.; Johnston, S.; Keith, M.; Reynolds, J. E.; Ransom, S. M.; Ray, P. S.; Wood, K. S.; Sarkissian, J. E-mail: fernando@astro.columbia.edu

    2012-03-20

    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.

  11. Three years of Fermi GBM Earth Occultation Monitoring: Observations of Hard X-ray/Soft Gamma-Ray Sources

    E-Print Network [OSTI]

    Jenke, P; Case, Gary L; Cherry, Michael L; Rodi, James; Camero-Arranz, Ascension; Chaplin, Vandiver; Beklen, Elif; Finger, Mark H; Bhat, Narayana; Briggs, Michael S; Connaughto, Valerie; Greiner, Jochen; Kippen, R Marc; Meegan, Charles A; Paciesas, William S; Preece, Robert; von Kienlin, Andreas

    2013-01-01

    The Gamma ray Burst Monitor (GBM) on board Fermi Gamma-ray Space Telescope has been providing continuous data to the astronomical community since 2008 August 12. We will present the results of the analysis of the first three years of these continuous data using the Earth occultation technique to monitor a catalog of 209 sources. Although the occultation technique is in principle quite simple, in practice there are many complications including the dynamic instrument response, source confusion, and scattering in the Earth's atmosphere, which will be described. We detect 99 sources, including 40 low-mass X-ray binary/neutron star systems, 31 high-mass X-ray binary/neutron star systems, 12 black hole binaries, 12 active galaxies, 2 other sources, plus the Crab Nebula and the Sun. Nine of these sources are detected in the 100-300 keV band, including seven black-hole binaries, the active galaxy Cen A, and the Crab. The Crab and Cyg X-1 are also detected in the 300-500 keV band. GBM provides complementary data to ot...

  12. Three years of Fermi GBM Earth Occultation Monitoring: Observations of Hard X-ray/Soft Gamma-Ray Sources

    E-Print Network [OSTI]

    Wilson-Hodge, Colleen A; Cherry, Michael L; Rodi, James; Camero-Arranz, Ascension; Jenke, Peter; Chaplin, Vandiver; Beklen, Elif; Finger, Mark; Bhat, Narayan; Briggs, Michael S; Connaughton, Valerie; Greiner, Jochen; Kippen, R Marc; Meegan, Charles A; Paciesas, William S; Preece, Robert; von Kienlin, Andreas

    2012-01-01

    The Gamma ray Burst Monitor (GBM) on board Fermi has been providing continuous data to the astronomical community since 2008 August 12. In this paper we present the results of the analysis of the first three years of these continuous data using the Earth occultation technique to monitor a catalog of 209 sources. From this catalog, we detect 102 sources, including 41 low-mass X-ray binary/neutron star systems, 33 high-mass X-ray binary neutron star systems, 12 black hole binaries, 12 active galaxies, 2 other sources, plus the Crab Nebula, and the Sun. Nine of these sources are detected in the 100-300 keV band, including seven black-hole binaries, the active galaxy Cen A, and the Crab. The Crab and Cyg X-1 are also detected in the 300-500 keV band. GBM provides complementary data to other sky-monitors below 100 keV and is the only all-sky monitor above 100 keV. Up-to-date light curves for all of the catalog sources can be found at http://heastro.phys.lsu.edu/gbm/.

  13. Latent instabilities in metallic LaNiO3 films by strain control of Fermi-surface topology

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

    Yoo, Hyang Keun; Hyun, Seung Ill; Moreschini, Luca; Kim, Hyeong-Do; Chang, Young Jun; Sohn, Chang Hee; Jeong, Da Woon; Sinn, Soobin; Kim, Yong Su; Bostwick, Aaron; et al

    2015-03-04

    Strain control is one of the most promising avenues to search for new emergent phenomena in transition-metal-oxide films. Here, we investigate the strain-induced changes of electronic structures in strongly correlated LaNiO3 (LNO) films, using angle-resolved photoemission spectroscopy and the dynamical mean-field theory. The strongly renormalized eg-orbital bands are systematically rearranged by misfit strain to change its fermiology. As tensile strain increases, the hole pocket centered at the A point elongates along the kz-axis and seems to become open, thus changing Fermi-surface (FS) topology from three- to quasi-two-dimensional. Concomitantly, the FS shape becomes flattened to enhance FS nesting. A FS superstructuremore »withQ15(1/2,1/2,1/2) appears in all LNO films, while a tensile-strained LNO film has an additional Q2 5 (1/4,1/4,1/4) modulation, indicating that some instabilities are present in metallic LNO films. Charge disproportionation and spin-density-wave fluctuations observed in other nickelates might be their most probable origins« less

  14. Evidence for a Common Physical Description of Non-Fermi-Liquid Behavior in Chemically Substituted f -Electron Systems

    SciTech Connect (OSTI)

    de Andrade, M.C.; Chau, R.; Dickey, R.P.; Dilley, N.R.; Freeman, E.J.; Gajewski, D.A.; Maple, M.B. [Department of Physics and Institute for Pure and Applied Physical Sciences, University of California, San Diego, La Jolla, California 92093 (United States)] [Department of Physics and Institute for Pure and Applied Physical Sciences, University of California, San Diego, La Jolla, California 92093 (United States); Movshovich, R. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)] [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Castro Neto, A.H.; Castilla, G. [Department of Physics, University of California, Riverside, California 92521 (United States)] [Department of Physics, University of California, Riverside, California 92521 (United States); Jones, B.A. [IBM Almaden Research Center, San Jose, California 95120-6099 (United States)] [IBM Almaden Research Center, San Jose, California 95120-6099 (United States)

    1998-12-01

    The non-Fermi-liquid (NFL) behavior observed in the low temperature specific heat C(T) and magnetic susceptibility {chi}(T) of many chemically substituted f -electron systems is analyzed within the context of a recently developed theory based on Griffiths{close_quote} singularities. Measurements of C(T) and {chi}(T) in the systems Th{sub 1{minus}x}U {sub x}Pd{sub 2}Al{sub 3} , Y{sub 1{minus}x}U {sub x}Pd{sub 3} , and UCu{sub 5{minus}x }M{sub x} (M=Pd,thinspPt ) are found to be consistent with C(T)/T{proportional_to}{chi}(T){proportional_to}T{sup {minus}1+{lambda}} predicted by this model with {lambda}{lt}1 in the NFL regime. These results suggest that the NFL properties observed in a wide variety of disordered f -electron systems can be described within the context of a common physical picture. {copyright} {ital 1998} {ital The American Physical Society}

  15. FERMI-LAT Observations of Supernova Remnant G5.7-0.1, Believed to be Interacting with Molecular Clouds

    E-Print Network [OSTI]

    Joubert, Timothy; Slane, Patrick; Gelfand, Joseph

    2015-01-01

    We report the detection of $\\gamma$-ray emission coincident with the supernova remnant (SNR) G5.7-0.1 using data from the Large Area Telescope on board the {\\it Fermi Gamma-ray Space Telescope}. SNR shocks are expected to be sites of cosmic ray acceleration, and clouds of dense material can provide effective targets for production of $\\gamma$-rays from $\\pi^0$-decay. The SNR is known to be interacting with molecular clouds, as evidenced by observations of hydroxyl (OH) maser emission at 1720 MHz in its direction. The observations reveal a $\\gamma$-ray source in the direction of SNR G5.7-0.1, positioned nearby the bright $\\gamma$-ray source SNR W28. We model the broadband emission (radio to $\\gamma$-ray) using a one-zone model, and after considering scenarios in which the MeV-TeV sources originate from either $\\pi^0$-decay or leptonic emission, conclude that a considerable component of the $\\gamma$-ray emission comes from the $\\pi^0$-decay channel. Finally, constraints were placed on the reported ambiguity of ...

  16. Pulse properties of terrestrial gamma-ray flashes detected by the Fermi Gamma-Ray Burst Monitor

    E-Print Network [OSTI]

    Foley, Suzanne; Briggs, Michael S; Connaughton, Valerie; Tierney, David; McBreen, Sheila; Dwyer, Joseph; Chaplin, Vandiver L; Bhat, P Narayana; Byrne, David; Cramer, Eric; Fishman, Gerald J; Xiong, Shaolin; Greiner, Jochen; Kippen, R Marc; Meegan, Charles A; Paciesas, William S; Preece, Robert D; von Kienlin, Andreas; Wilson-Hodge, Colleen

    2015-01-01

    The Gamma-ray Burst Monitor (GBM) on board the Fermi Gamma-ray Space Telescope has triggered on over 300 terrestrial gamma-ray flashes (TGFs) since its launch in June 2008. With 14 detectors, GBM collects on average ~100 counts per triggered TGF, enabling unprecedented studies of the time profiles of TGFs. Here we present the first rigorous analysis of the temporal properties of a large sample of TGFs (278), including the distributions of the rise and fall times of the individual pulses and their durations. A variety of time profiles are observed with 19 of TGFs having multiple pulses separated in time and 31 clear cases of partially overlapping pulses. The effect of instrumental dead time and pulse pileup on the temporal properties are also presented. As the observed gamma ray pulse structure is representative of the electron flux at the source, TGF pulse parameters are critical to distinguish between relativistic feedback discharge and lightning leader models. We show that at least 67% of TGFs at satellite ...

  17. Constraining Dark Matter Models from a Combined Analysis of Milky Way Satellites with the Fermi Large Area Telescope

    SciTech Connect (OSTI)

    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..

    2012-09-14

    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.

  18. CONSTRAINTS ON THE SYNCHROTRON SHOCK MODEL FOR THE FERMI GRB 090820A OBSERVED BY GAMMA-RAY BURST MONITOR

    SciTech Connect (OSTI)

    Burgess, J. Michael; Preece, Robert D.; Briggs, Michael S.; Connaughton, Valerie; Guiriec, Sylvain; Paciesas, William S.; Bhat, P. N.; Chaplin, Vandiver; Goldstein, Adam; Baring, Matthew G.; Meegan, Charles A.; Bissaldi, Elisabetta; Diehl, Roland; Greiner, Jochen; Gruber, David; Fishman, Gerald J.; Gibby, Melissa; Giles, Misty E-mail: baring@rice.edu

    2011-11-01

    Discerning the radiative dissipation mechanism for prompt emission in gamma-ray bursts (GRBs) requires detailed spectroscopic modeling that straddles the {nu}F{sub {nu}} peak in the 100 keV-1 MeV range. Historically, empirical fits such as the popular Band function have been employed with considerable success in interpreting the observations. While extrapolations of the Band parameters can provide some physical insight into the emission mechanisms responsible for GRBs, these inferences do not provide a unique way of discerning between models. By fitting physical models directly, this degeneracy can be broken, eliminating the need for empirical functions; our analysis here offers a first step in this direction. One of the oldest, and leading, theoretical ideas for the production of the prompt signal is the synchrotron shock model. Here we explore the applicability of this model to a bright Fermi gamma-ray burst monitor (GBM) burst with a simple temporal structure, GRB 090820A. Our investigation implements, for the first time, thermal and non-thermal synchrotron emissivities in the RMFIT forward-folding spectral analysis software often used in GBM burst studies. We find that these synchrotron emissivities, together with a blackbody shape, provide at least as good a match to the data as the Band GRB spectral fitting function. This success is achieved in both time-integrated and time-resolved spectral fits.

  19. Short Gamma-Ray Bursts with Extended Emission Observed with Swift/BAT and Fermi/GBM

    E-Print Network [OSTI]

    Kaneko, Y; Gogus, E; Lin, L

    2015-01-01

    Some short GRBs are followed by longer extended emission, lasting anywhere from ~10 to ~100 s. These short GRBs with extended emission (EE) can possess observational characteristics of both short and long GRBs (as represented by GRB 060614), and the traditional classification based on the observed duration places some of them in the long GRB class. While GRBs with EE pose a challenge to the compact binary merger scenario, they may therefore provide an important link between short and long duration events. To identify the population of GRBs with EE regardless of their initial classifications, we performed a systematic search of short GRBs with EE using all available data (up to February 2013) of both Swift/BAT and Fermi/GBM. The search identified 16 BAT and 14 GBM detected GRBs with EE, several of which are common events observed with both detectors. We investigated their spectral and temporal properties for both the spikes and the EE, and examined correlations among these parameters. Here we present the resul...

  20. Latent instabilities in metallic LaNiO? films by strain control of Fermi-surface topology

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

    Yoo, Hyang Keun; Hyun, Seung Ill; Moreschini, Luca; Kim, Hyeong -Do; Chang, Young Jun; Sohn, Chang Hee; Jeong, Da Woon; Sinn, Soobin; Kim, Yong Su; Bostwick, Aaron; et al

    2015-03-04

    Strain control is one of the most promising avenues to search for new emergent phenomena in transition metal-oxide films. Here, we investigate the strain-induced changes of electronic structures in strongly correlated LaNiO? (LNO) films, using angle-resolved photoemission spectroscopy and the dynamical mean-field theory. The strongly renormalized eg-orbital bands are systematically rearranged by misfit strain to change its fermiology. As tensile strain increases, the hole pocket centered at the A point elongates along the kz-axis and seems to become open, thus changing Fermi-surface (FS) topology from three- to quasi-two-dimensional. Concomitantly, the FS shape becomes flattened to enhance FS nesting. A FSmore »superstructure withQ? = (1/2,1/2,1/2) appears in all LNO films, while a tensile-strained LNO film has an additional Q? = (1/4,1/4,1/4) modulation, indicating that some instabilities are present in metallic LNO films. Charge disproportionation and spin-density-wave fluctuations observed in other nickelates might be their most probable origins« less