Interviews in Washington, DC for Albert Einstein Fellowship Semi-Finalists
Broader source: Energy.gov [DOE]
Selected semi-finalists in the Albert Einstein Distinguished Educator Fellowship are invited to DC for interviews.
Albert Einstein - Hanford Site
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Albert Einstein Alerts President Roosevelt of German Atomic Energy...
National Nuclear Security Administration (NNSA)
Albert Einstein Alerts President Roosevelt of German Atomic Energy Program | National Nuclear Security Administration Facebook Twitter Youtube Flickr RSS People Mission Managing...
Albert Einstein Distinguished Educator Fellowship Program accepting...
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a unique opportunity for accomplished K-12 science, technology, engineering and mathematics (STEM) educators to serve 11 months in a Federal agency or U.S. Congressional...
Albert Einstein Distinguished Educator Fellowship Program accepting
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Albert Einstein, 1905: Ein 3-Gange Menu
Buse, Karsten
Materie Dalton #12;· 1811 Avogadro: Gleiches Volumen f¨ur verschiedene Gase hat gleiche ZAHL von Atomen - Fl¨ussig, 1000x dichter, dichtgepackt · Atom-radius 10-10 meter · Einstein Avogadro #12;Kinetische
Zurek awarded Albert Einstein professorship prize
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Albert Einstein Distinguished Educator Fellowship (AEF) Program Homepage |
Office of Science (SC) Website
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Albert Einstein College of Medicine Amendment to Non-human Use of Radioactive Material License
Emmons, Scott
RSO-2 Rev.0 Albert Einstein College of Medicine Amendment to Non-human Use of Radioactive Material Present Total Quantity (mCi) New Total Quantity (mCi) Max. Amount per Experiment (mCi) Chemical Form: If yes, please explain: 3. Radiation Protection: Check special equipment to be used to control radiation
Albert Einstein's close friends and colleagues from the Patent Office
Weinstein, Galina
2012-01-01
In the Patent Office Einstein hatched his most beautiful ideas, and there he spent his "Happy Bern Years". These wonderful ideas led to his miraculous year works of 1905. Einstein was not an expert in academic matters, and he was out of academic world. Neither did he meet influential professors, or attend academic meetings. He discussed his ideas with his close friends and colleagues from the Patent Office. In 1907 he finally got his foot into the academic doorway; Einstein became a privatdozent and gave lectures at the University of Bern. However, his first students consisted again of his two close friends and another colleague from the Patent Office.
ALBERT EINSTEIN COLLEGE OF MEDICINE OF YESHIVA UNIVERSITY
Emmons, Scott
's Responsibility E-MAIL peter.babin@einstein.yu.edu PHONE: (718) 430-2243 Dosimeter/Film Badge Request the individual wear a dosimeter at his/her previous place of employment? Yes: No: If yes, complete the exposure
Pfeifer, Holger
Ulm University | International Graduate School in Molecular Medicine Ulm | Albert-Einstein-Allee 11, O 25 | 89081 Ulm International Graduate School in Molecular Medicine Ulm, Albert-Einstein-Allee 11 to the exam. Study Programme: International PhD Programme in Molecular Medicine Last Name
Albert Einstein Distinguished Educator Fellowship Act of 1994 in U.S.C. |
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
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2013 Fall : Distinguished Honors Distinguished
Kunkle, Tom
Distinguished Barnes Elizabeth Pate Distinguished Barth Caitlin Elizabeth Distinguished Bartley Dylan Lake Becker-Krail Darius Demetrius Distinguished Bell Stephen Joseph Distinguished Benfield Katherine Distinguished Carey Caitlin Elizabeth Distinguished Carl Emma Leah Distinguished Carls
2010 Spring : Distinguished Honors Distinguished
Kunkle, Tom
Caitlin Alice Distinguished Barton Cory A Distinguished Bath Sean C Distinguished Beasley Elizabeth Lines Kaitlyn Distinguished Behrens Marissa Alison Distinguished Behringer Steven James Distinguished Bell Brant Caitlin Victoria Distinguished Breunsbach Jeffrey William Distinguished Brezina Sara Ann
2009 Fall : Distinguished Honors Distinguished
Kunkle, Tom
Bell Lorin Legene Distinguished Bellamy Kara Nicole Distinguished Benjamin Abigail Distinguished Bergman Kelsey Jean Distinguished Bettendorf Caitlin Marie Distinguished Bevacqua Kayla Marie Robyn Jane Distinguished Busby Caitlin McCushing Distinguished Buschur William H Distinguished Buskirk
2014 Fall : Distinguished Honors Distinguished
Kunkle, Tom
: Distinguished Honors LAST_NAME FIRST_NAME MIDDLE_NAME HONORS Barry Kendall Kathleen Distinguished Barth Caitlin Brielen Hunter Distinguished Beck Morgan Elyse Distinguished Bednar Alexander Barrett Distinguished Bell
THE CAMPAIGN TO TRANSFORM EINSTEIN 2 THE CAMPAIGN TO TRANSFORM EINSTEIN
Emmons, Scott
THE CAMPAIGN TO TRANSFORM EINSTEIN #12;2 THE CAMPAIGN TO TRANSFORM EINSTEIN #12;ALBERT EINSTEIN, resulting in a significant reduction in potential new treatments coming to market. This makes our work on a new chapter of growth and transformative change. With the guidance and full support of our Board
2012 Spring : Highly Distinguished Honors Highly Distinguished
Kunkle, Tom
Distinguished Bell Lauren Ashley Highly Distinguished Benjamin Abigail Highly Distinguished Benson Alexandrea Hannah Elizabeth Highly Distinguished Bishop Anna Laurel Highly Distinguished Black Caitlin Emily Highly
2014 Fall : Highly Distinguished Honors Highly Distinguished
Kunkle, Tom
Morgan Highly Distinguished Beech Kaylie Schaefer Highly Distinguished Bell Brandi Lakeisha Highly Distinguished Billard Caitlin Rose Highly Distinguished Birk Christian Gustave Highly Distinguished Birkhead
2011 Fall : Highly Distinguished Honors Highly Distinguished
Kunkle, Tom
Distinguished Beidler Katilyn V. Highly Distinguished Belanger Brett Russell Highly Distinguished Bell Lauren Ashley Highly Distinguished Bennett Caitlin Renee Highly Distinguished Berdusco Ann Marie Highly Highly Distinguished Bertel Jeffrey Robert Highly Distinguished Bettendorf Caitlin Marie Highly
This article was downloaded by:[Newen, Albert] [Newen, Albert
Indiana University
Number: 1072954 Registered office: Mortimer House, 37-41 Mortimer Street, London W1T 3JH, UK: http://www.informaworld.com/smpp/title~content=t713441835 Animal Minds and the Possession of Concepts To cite this Article: Newen, Albert and Bartels, Andreas , 'Animal Minds and the Possession of Concepts
Albert Polman Center for Nanophotonics
Polman, Albert
;Third-generation photovoltaics M. Green, UNSW #12;H. Atwater (CALTECH) "Quantum defect" problem #12;H (traditional) biomass (advanced) solar power (photovoltaics (PV) & solar thermal generation (CSP) solar thermalAlbert Polman Center for Nanophotonics FOM-Institute AMOLF Amsterdam Photovoltaics Solving a big
ALBERT EINSTEIN COLLEGE OF MEDICINE COMMITTEE ON GRADUATE MEDICAL EDUCATION
Emmons, Scott
- Voluntary - Mandatory to include fitness for duty evaluations · End of rotation debriefing · Establish
The Albert Einstein College of Medicine of Yeshiva University
Jenny, Andreas
............................................................................................................................. 20 FIRE 21 HAZARDOUS MATERIALS 22 HAZARDOUS MATERIALS SPECIAL 24 HAZARD INDICATORS...................................................................................................................... 26 HAZARDOUS MATERIALS 27 HAZARDOUS MATERIALS 28 MAJOR NATURAL DISASTERS and Emergency Numbers......... 66 APPENDIX 4 Location of Safety Data Sheet Stations...................................
Albert Einstein Alerts President Roosevelt of German Atomic Energy Program
National Nuclear Security Administration (NNSA)
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None
2011-04-25
Commémoration de A.Einstein avec 4 orateurs pour honnorer sa mémoire: le prof.Weisskopf parlera de l'homme de science engagé, Daniel Amati du climat de la physique aux années 1920, Sergio Fubini de l'heure scientifique d'A.Einstein et le prof.Berob(?)
Honorary Doctor of Science Sir Eric Albert ASH
Po, Lai-Man
Honorary Doctor of Science Sir Eric Albert ASH Chancellor: Sir Eric Albert Ash attended is meeting Clare, his wife, who was a graduate student at Stanford at that time. We are honoured that Mrs Ash of the University Council, I request you to confer on Sir Eric Albert Ash the Honorary Degree of Doctor of Science
Primack, Joel (University of California, Santa Cruz) [University of California, Santa Cruz
2007-10-08
The National Academy of Sciences was commissioned in 2006 to report on how to restart the Beyond Einstein program, which includes missions to understand dark energy, test general relativity, and observe gravity waves from merging supermassive black holes. This colloquium by one of the members of the recently released Academy study will explain the research strategy that the report proposes and its implications for continued U.S. participation in the exploration of the universe.
Argerami, Martin
(Local and International Beers) Near the campus and the suggested hotels · Brewster's Brewing Co. & Restaurant, 4180 Albert Street. 522.2739 · Bonzinni's Brew Pub, 4634 Albert Street. 586.3553 · Triffon's Pizza, 1101 Kramer Boulevard. 584.0040 Downtown · Bushwakker Brewing Co. 2206 Dewdney Avenue. 359
LANL Distinguished Postdoc Fellows
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Einstein's Equation in Pictures
Matthew Frank
2002-03-28
This paper gives a self-contained, elementary, and largely pictorial statement of Einstein's equation.
Termination Analysis of Java Bytecode Elvira Albert1
Arenas, Puri
program properties is often split into separately proving partial correctness and termination. ObjectTermination Analysis of Java Bytecode Elvira Albert1 , Puri Arenas1 , Michael Codish2 , Samir Abstract. Termination analysis has received considerable attention, traditionally in the context
Quantum Physics Einstein's Gravity
Visser, Matt
Quantum Physics confronts Einstein's Gravity Matt Visser Physics Department Washington University Saint Louis USA Science Saturdays 13 October 2001 #12; Quantum Physics confronts Einstein's Gravity and with Einstein's theory of gravity (the general relativity) is still the single biggest theoretical problem
International Association for Cryptologic Research (IACR)
Fletcher, Albert Kwon, Marten van Dijk, Srinivas Devadas Massachusetts Institute of Technology - {yxy
Domingos Soares
2012-03-26
Einstein's static model is the first relativistic cosmological model. The model is static, finite and of spherical spatial symmetry. I use the solution of Einstein's field equations in a homogeneous and isotropic universe -- Friedmann's equation -- to calculate the radius of curvature of the model (also known as "Einstein's universe"). Furthermore, I show, using a Newtonian analogy, the model's mostly known feature, namely, its instability under small perturbations on the state of equilibrium.
Albert R. Mann Library Government Information Policy and Procedure Manual
Angenent, Lars T.
code, regulations, and serve as a primary source of statistical data. Government information acquiredAlbert R. Mann Library Government Information Policy and Procedure Manual Table of Contents and damaged information Acquisitions Acquisitions activities 1. Item selection profile 2. Shipment delivery 3
Amtliche Bekanntmachungen DER ALBERT-LUDWIGS-UNIVERSITT FREIBURG IM BREISGAU
Just, Armin
(Landeshochschulgesetz-LHG) vom 01.01.2005 in der Fassung von Artikel 1 des Gesetzes vom 01. 04. 2014 (GBl. S. 99) hat der Senat der Albert-Ludwigs-Universität Freiburg gem. § 19 Abs. 1 Satz 2 Ziff. 10 LHG in seiner Dauer ihres Aufenthalts am FRIAS Mitglieder der Universität gemäß § 9 Abs. 1 LHG. § 3 Direktorium (1
A novel hybrid carbon material ALBERT G. NASIBULIN1
.2007.37 Both fullerenes and single-walled carbon nanotubes (SWNTs) exhibit many advantageous properties functionalization), we varied the reactor temperature and the concentrations of water vapour and carbon dioxide (seeA novel hybrid carbon material ALBERT G. NASIBULIN1 , PETER V. PIKHITSA2 , HUA JIANG3 , DAVID P
2015 Spring : Highly Distinguished Honors As of: Jun 12, 2015
Kunkle, Tom
Hunter Highly Distinguished Barry Madeline Regan Highly Distinguished Barth Caitlin Elizabeth Highly Garrett Robert Highly Distinguished Belcher Harlan Lloyd Highly Distinguished Bell Brandi Lakeisha Highly Distinguished Bell Stephen Joseph Highly Distinguished Bello Austin Tyler Highly Distinguished Bennett Meredith
Piccioni, Robert
2014-06-25
Young Einstein was a rebel who seemed doomed to fail. How did he overcome rejection to become the most famous scientist in history? We will discuss and explain all his theories in plain English and without math, and we will discover how Einstein's achievements impact our lives through DVDs, GPS, iPods, computers and green energy.
Frey, H. Christopher
Alcoa Foundation Engineering Research Awards Distinguished = THE ALCOA FOUNDATION DISTINGUISHED ENGINEERING RESEARCH AWARD Achievement = THE ALCOA FOUNDATION ENGINEERING RESEARCH ACHIEVEMENT AWARD 2015 Youngsoo "Richard" Kim, Civil, Construction, and Environmental Engineering, Distinguished Yong Zhu
Greenslade, Diana
June 2015) · Flood Risk · Previous Flooding · Flood Forecasting · Local Information · Flood Warnings Flood Risk The Logan River has a catchment area of about 3850 square kilometres and lies in the south and Albert FLOOD WARNING SYSTEM for the LOGAN & ALBERT RIVERS This brochure describes the flood warning
Albert "Al" J. Williams | Department of Energy
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Albert City, Iowa: Energy Resources | Open Energy Information
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Distinguished trajectories in time dependent vector fields
J. A. Jimenez Madrid; Ana M. Mancho
2009-02-16
We introduce a new definition of distinguished trajectory that generalises the concepts of fixed point and periodic orbit to aperiodic dynamical systems. This new definition is valid for identifying distinguished trajectories with hyperbolic and non-hyperbolic types of stability. The definition is implemented numerically and the procedure consist in determining a path of limit coordinates. It has been successfully applied to known examples of distinguished trajectories. In the context of highly aperiodic realistic flows our definition characterises distinguished trajectories in finite time intervals, and states that outside these intervals trajectories are no longer distinguished.
Y. S. Kim
2011-12-02
In 1905, Einstein formulated his special relativity for point particles. For those particles, his Lorentz covariance and energy-momentum relation are by now firmly established. How about the hydrogen atom? It is possible to perform Lorentz boosts on the proton assuming that it is a point particle. Then what happens to the electron orbit? The orbit could go through an elliptic deformation, but it is not possible to understand this problem without quantum mechanics, where the orbit is a standing wave leading to a localized probability distribution. Is this concept consistent with Einstein's Lorentz covariance? Dirac, Wigner, and Feynman contributed important building blocks for understanding this problem. The remaining problem is to assemble those blocks to construct a Lorentz-covariant picture of quantum bound states based on standing waves. It is shown possible to assemble those building blocks using harmonic oscillators.
T. Damour
1994-12-21
The confrontation between General Relativity and experimental results, notably binary pulsar data, is summarized and its significance discussed. The agreement between experiment and theory is numerically very impressive. However, some recent theoretical findings (existence of non-perturbative strong-field effects, natural cosmological attraction toward zero scalar couplings) suggest that the present agreement between Einstein's theory and experiment might be a red herring and provide new motivations for improving the experimental tests of gravity.
Nicolas Yunes
2015-10-13
This is an article commissioned by the Spanish Physics Magazine ("Revista Espa\\~nola de F\\'isica") for the Centennial Anniversary of the discovery of General Relativity. The article reviews experimental and observational efforts to test Einstein's theory of General Relativity in a variety of scenarios (from the Solar System to binary pulsars, from the Sag A* to binary black hole and neutron star coalescences).
West Indian mammals from the Albert Schwartz Collection: Biological and historical information
Timm, Robert M.; Genoways, Hugh H.
2003-06-01
In the period 1954-1976, Albert Schwartz and several students working with him made extensive collections of mammals (ca. 2,000 specimens), reptiles and amphibians, birds, and butterflies in the West Indies. Schwartz's ...
Liouville gravity from Einstein gravity
D. Grumiller; R. Jackiw
2007-12-28
We show that Liouville gravity arises as the limit of pure Einstein gravity in 2+epsilon dimensions as epsilon goes to zero, provided Newton's constant scales with epsilon. Our procedure - spherical reduction, dualization, limit, dualizing back - passes several consistency tests: geometric properties, interactions with matter and the Bekenstein-Hawking entropy are as expected from Einstein gravity.
Argonne announces 2015 Distinguished Fellows | Argonne National...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
EmailPrint The U.S. Department of Energy's Argonne National Laboratory has named Barry Smith, Charles Macal and Branko Ruscic as its 2015 Distinguished Fellows. The Argonne...
JACK E. CERMAK University Distinguished Professor Emeritus
Connors, Daniel A.
JACK E. CERMAK University Distinguished Professor Emeritus 50 YEARS OF WIND ENGINEERING DEVELOPMENTS #12;The Beginning Colorado State University Wind Tunnel Constructed in 1949 Jack Cermak & BFarland Wind-chill Investigation of Artic Clothing for the Environmental Research Section, Department
2015 Mathematics & Actuarial Science Distinguished Alumni ...
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CEO/president and co-founder of multiple start-ups in the oil and gas and the technology sectors, Paula deWitte has a distinguished and multi-faceted career as ...
Einstein's unpublished opening lecture for his course on relativity theory in Argentina, 1925
Alejandro Gangui; Eduardo L. Ortiz
2009-03-11
In 1922 the University of Buenos Aires (UBA) Council approved a motion to send an invitation to Albert Einstein to visit Argentina and give a course of lectures on his theory of relativity. The motion was proposed by Jorge Duclout (1856-1927), who had been educated at the Eidgenossische Technische Hochschule, Zurich (ETH). This proposal was the culmination of a series of initiatives of various Argentine intellectuals interested in the theory of relativity. In a very short time Dr. Mauricio Nirenstein (1877-1935), then the university's administrative secretary, fulfilled all the requirements for the university's invitation to be endorsed and delivered to the sage in Berlin. The visit took place three years later, in March-April 1925. The Argentine press received Einstein with great interest and respect; his early exchanges covered a wide range of topics, including international politics and Jewish matters. Naturally, the journalists were more eager to hear from the eminent pacifist than from the incomprehensible physicist. However, after his initial openness with the press, the situation changed and Einstein restricted his public discourse to topics on theoretical physics, avoiding some controversial political, religious, or philosophical matters that he had freely touched upon in earlier interviews.. [abridged].
Atwater, Harry
Nanophotonic design principles for ultrahigh efficiency photovoltaics Harry Atwater, Albert Polman for ultrahigh efficiency photovoltaics Harry Atwater, 1,2 Albert Polman,2,1 , Emily Kosten, Dennis Callahan1 can enable ultrahigh efficiencies previously considered to be out of reach. Photovoltaic technology
Abell Endowment Distinguished Lecture in Computer Engineering,
Abell Endowment Distinguished Lecture in Computer Engineering, in conjunction with the Electrical and Computer Engineering Seminar Series and the Computer Science Department Seminar Series "Parallex: An Innovative Execution Model for Exascale Computing" by Thomas Sterling, Ph.D Professor, School of Informatics
Completely distinguishable projections of spatial graphs
Nikkuni, Ryo
. 1.1. We can obtain the eight spatial embeddings g1, g2, . . . , g8 of G from ^f as illustrated 2 3 4 5 6 g1 g2 g3 g4 g5 g6 g7 g8 Fig. 1.2. 2 #12;2. Completely distinguishable projections
Colored HOMFLY polynomials can distinguish mutant knots
Satoshi Nawata; P. Ramadevi; Vivek Kumar Singh
2015-04-01
We illustrate from the viewpoint of braiding operations on WZNW conformal blocks how colored HOMFLY polynomials with multiplicity structure can detect mutations. As an example, we explicitly evaluate the (2,1)-colored HOMFLY polynomials that distinguish a famous mutant pair, Kinoshita-Terasaka and Conway knot.
Civil & Environmental Engineering Distinguished Seminar Series
life. Mild wind may provide us useful electric energy in addition to positive effects on urban will be discussed in this talk. Moreover a methodology of using small wind turbines for dual purposes, improvingCivil & Environmental Engineering Distinguished Seminar Series Soon-Duck Kwon, Ph. D. KOCED Wind
Distinguishing technicolor models via tt production at polarized...
Office of Scientific and Technical Information (OSTI)
Distinguishing technicolor models via tt production at polarized photon colliders Citation Details In-Document Search Title: Distinguishing technicolor models via tt production at...
Coarse-grained distinguishability of field interactions
Bény, Cédric
2015-01-01
Information-theoretical quantities such as statistical distinguishability typically result from optimisations over all conceivable observables. Physical theories, however, are not generally considered valid for all mathematically allowed measurements. For instance, quantum field theories are not meant to be correct or even consistent at arbitrarily small lengthscales. A general way of limiting such an optimisation to certain observables is to first coarse-grain the states by a quantum channel. We show how to calculate contractive quantum information metrics on coarse-grained equilibrium states of free bosonic systems (Gaussian states), in directions generated by arbitrary perturbations of the Hamiltonian. As an example, we study the Klein-Gordon field. If the phase-space resolution is coarse compared to h-bar, the various metrics become equal and the calculations simplify. In that context, we compute the scale dependence of the distinguishability of the quartic interaction.
Coarse-grained distinguishability of field interactions
Cédric Bény
2015-09-10
Information-theoretical quantities such as statistical distinguishability typically result from optimisations over all conceivable observables. Physical theories, however, are not generally considered valid for all mathematically allowed measurements. For instance, quantum field theories are not meant to be correct or even consistent at arbitrarily small lengthscales. A general way of limiting such an optimisation to certain observables is to first coarse-grain the states by a quantum channel. We show how to calculate contractive quantum information metrics on coarse-grained equilibrium states of free bosonic systems (Gaussian states), in directions generated by arbitrary perturbations of the Hamiltonian. As an example, we study the Klein-Gordon field. If the phase-space resolution is coarse compared to h-bar, the various metrics become equal and the calculations simplify. In that context, we compute the scale dependence of the distinguishability of the quartic interaction.
Albert Levi, Ph.D. Sabanci University, Orhanli, Tuzla, Istanbul 34956, Turkey
Levi, Albert
Albert Levi, Ph.D. Sabanci University, Orhanli, Tuzla, Istanbul 34956, Turkey Tel : + 90 (216) 483 and Natural Sciences, Sabanci University, Istanbul, Turkey 2002 Â 2007 Assistant Prof. of Computer Science and Engineering, Faculty of Engineering and Natural Sciences, Sabanci University, Istanbul, Turkey 2001 Â 2002
AlbertA Space program alberta Space program boundleSS opportunity
MacMillan, Andrew
AlbertA Space program alberta Space program boundleSS opportunity Alberta is a national leader in space sciences and that leadership starts at our universities. The Universities of Alberta, Calgary. Partnerships with Alberta's Universities will be key to leading future Alberta space innovation in the decades
SDJS: Efficient Statistics in Wireless Networks Albert Krohn, Michael Beigl, Sabin Wendhack
Beigl, Michael
- width and therefore as well energy in frequently chang- ing environments with many network nodes. OneSDJS: Efficient Statistics in Wireless Networks Albert Krohn, Michael Beigl, Sabin Wendhack Jam Signalling (SDJS) is a new transmission scheme targeted to highly mobile and ad hoc wireless
COMPRESSED REMOTE SENSING OF SPARSE OBJECTS ALBERT C. FANNJIANG, PENGCHONG YAN, AND THOMAS STROHMER
Fannjiang, Albert
COMPRESSED REMOTE SENSING OF SPARSE OBJECTS ALBERT C. FANNJIANG, PENGCHONG YAN, AND THOMAS STROHMER sensing. By introducing the sensor as well as target ensembles, the maximum number of recoverable targets that in many imaging applications the targets are sparse in the sense that they typically occupy a small
Nuclear structure effects in light muonic atoms Krzysztof Pachucki and Albert Wienczek
Pachucki, Krzysztof
Nuclear structure effects in light muonic atoms Krzysztof Pachucki and Albert Wienczek Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland (Dated: April 28, 2015) Nuclear structure corrections to energy levels of light muonic atoms are derived with particu- lar attention to the nuclear mass
Internet Protocol version 6 Overview* Albert Cabellos-Aparicio, Jordi Domingo-Pascual
PolitÃ¨cnica de Catalunya, Universitat
Internet Protocol version 6 Overview* Albert Cabellos-Aparicio, Jordi Domingo-Pascual Departament d stands for "Internet Protocol" and it was designed during the `70s with the purpose of interconnecting heterogeneous network technologies. IP was a huge success, and made it possible to create today's Internet
Einstein's energy-free gravitational field
Dalton, K
1995-01-01
In his founding paper on general relativity, Einstein rejected the differential law of energy-momentum conservation, T^{\\mu\
Distinguishing quantum and classical transport through nanostructures
Neill Lambert; Clive Emary; Yueh-Nan Chen; Franco Nori
2010-08-23
We consider the question of how to distinguish quantum from classical transport through nanostructures. To address this issue we have derived two inequalities for temporal correlations in nonequilibrium transport in nanostructures weakly coupled to leads. The first inequality concerns local charge measurements and is of general validity; the second concerns the current flow through the device and is relevant for double quantum dots. Violation of either of these inequalities indicates that physics beyond that of a classical Markovian model is occurring in the nanostructure.
Argonne Distinguished Fellows | Argonne National Laboratory
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
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United states Department of the Interior, Oscar L. Chapman, Fish and fildl i fe Service , Albert f1 are equipped with motors with the propeller mounted on one side. Others have twin engines with propellers
Beigl, Michael
Typical Sensors needed in Ubiquitous and Pervasive Computing Michael Beigl, Albert Krohn, Tobias and presents an overview of their characteristics. Keywords: ubiquitous and pervasive computing, networked for networked embedded sensor systems, especially in ubiquitous and pervasive computing settings. Several
Larry Band Voit Gilmore Distinguished Professor in Geography
McLaughlin, Richard M.
Larry Band Voit Gilmore Distinguished Professor in Geography Carolina Department of Environment and Natural Resources to improve the process
Do open clusters have distinguishable chemical signatures?
Blanco-Cuaresma, S; Heiter, U
2015-01-01
Past studies have already shown that stars in open clusters are chemically homogeneous (e.g. De Silva et al. 2006, 2007 and 2009). These results support the idea that stars born from the same giant molecular cloud should have the same chemical composition. In this context, the chemical tagging technique was proposed by Freeman et al. 2002. The principle is to recover disrupted stellar clusters by looking only to the stellar chemical composition. In order to evaluate the feasibility of this approach, it is necessary to test if we can distinguish between stars born from different molecular clouds. For this purpose, we studied the chemical composition of stars in 32 old and intermediate-age open clusters, and we applied machine learning algorithms to recover the original cluster by only considering the chemical signatures.
California Policy Should Distinguish Biofuels by Differential Global Warming Effects
Kammen, Daniel M.
California Policy Should Distinguish Biofuels by Differential Global Warming Effects by Richard J: _______________________________________ Date #12;California Policy Should Distinguish Biofuels by Differential Global Warming Effects Richard J, 2006 #12;#12;ABSTRACT California Policy Should Distinguish Biofuels by Differential Global Warming
Polymer Bose--Einstein Condensates
E. Castellanos; G. Chacon-Acosta
2013-01-22
In this work we analyze a non--interacting one dimensional polymer Bose--Einstein condensate in an harmonic trap within the semiclassical approximation. We use an effective Hamiltonian coming from the polymer quantization that arises in loop quantum gravity. We calculate the number of particles in order to obtain the critical temperature. The Bose--Einstein functions are replaced by series, whose high order terms are related to powers of the polymer length. It is shown that the condensation temperature presents a shift respect to the standard case, for small values of the polymer scale. In typical experimental conditions, it is possible to establish a bound for $\\lambda^{2}$ up to $ \\lesssim 10 ^{-16}$m$^2$. To improve this bound we should decrease the frequency of the trap and also decrease the number of particles.
Entropic corrections to Einstein equations
Hendi, S. H. [Physics Department, College of Sciences, Yasouj University, Yasouj 75914 (Iran, Islamic Republic of); Research Institute for Astronomy and Astrophysics of Maragha (RIAAM), Maragha (Iran, Islamic Republic of); Sheykhi, A. [Research Institute for Astronomy and Astrophysics of Maragha (RIAAM), Maragha (Iran, Islamic Republic of); Department of Physics, Shahid Bahonar University, P.O. Box 76175-132, Kerman (Iran, Islamic Republic of)
2011-04-15
Considering the general quantum corrections to the area law of black hole entropy and adopting the viewpoint that gravity interprets as an entropic force, we derive the modified forms of Modified Newtonian dynamics (MOND) theory of gravitation and Einstein field equations. As two special cases we study the logarithmic and power-law corrections to entropy and find the explicit form of the obtained modified equations.
Einstein's Apple and Relativity's Gravitational Field
Engelbert L. Schucking
2009-03-31
The foundations of Einstein's first (1907) principle of equivalence are explored and their consequences are stated in terms of invariance under generalized Lorentz transformations, first explored by Hessenberg.
INVERSE PROBLEMS FOR EINSTEIN MANIFOLDS 1. Introduction ...
2008-12-11
principle is that Einstein's equation becomes a non-linear elliptic system with real ...... manifolds with boundary, Communications in Analysis and Geometry 11 ...
Local distinguishability with preservation of entanglement
Scott M. Cohen
2007-06-25
I consider deterministic distinguishability of a set of orthogonal, bipartite states when only a single copy is available and the parties are restricted to local operations and classical communication, but with the additional requirement that entanglement must be preserved in the process. Several general theorems aimed at characterizing sets of states with which the parties can succeed in such a task are proven. These include (1) a maximum for the number of states when the Schmidt rank of every outcome must be at least a given minimum; (2) an upper bound (equal to the dimension of Hilbert space if entanglement need not be preserved) for the sum over Schmidt ranks of the initial states when only one-way classical communication is allowed; and (3) separately, a necessary and a sufficient condition on the states such that their original Schmidt ranks can always be preserved. It is shown that our bound on the sum of Schmidt ranks can be exceeded if two-way communication is permitted, and this includes the case that entanglement need not be preserved, so that this sum can exceed the dimension of Hilbert space. Such questions, concerning how the various results are effected by the resources used by the parties are addressed for each theorem. This subject is closely related to the problem of locally purifying an entangled state from a mixed state, which is of direct relevance to teleportation and dense coding using a mixed-state resource. In an appendix, I give an extremely simple and transparent proof of "non-locality without entanglement", a phenomenon originally discussed by Bennett and co-workers several years ago.
LDRD 149045 final report distinguishing documents.
Mitchell, Scott A.
2010-09-01
This LDRD 149045 final report describes work that Sandians Scott A. Mitchell, Randall Laviolette, Shawn Martin, Warren Davis, Cindy Philips and Danny Dunlavy performed in 2010. Prof. Afra Zomorodian provided insight. This was a small late-start LDRD. Several other ongoing efforts were leveraged, including the Networks Grand Challenge LDRD, and the Computational Topology CSRF project, and the some of the leveraged work is described here. We proposed a sentence mining technique that exploited both the distribution and the order of parts-of-speech (POS) in sentences in English language documents. The ultimate goal was to be able to discover 'call-to-action' framing documents hidden within a corpus of mostly expository documents, even if the documents were all on the same topic and used the same vocabulary. Using POS was novel. We also took a novel approach to analyzing POS. We used the hypothesis that English follows a dynamical system and the POS are trajectories from one state to another. We analyzed the sequences of POS using support vector machines and the cycles of POS using computational homology. We discovered that the POS were a very weak signal and did not support our hypothesis well. Our original goal appeared to be unobtainable with our original approach. We turned our attention to study an aspect of a more traditional approach to distinguishing documents. Latent Dirichlet Allocation (LDA) turns documents into bags-of-words then into mixture-model points. A distance function is used to cluster groups of points to discover relatedness between documents. We performed a geometric and algebraic analysis of the most popular distance functions and made some significant and surprising discoveries, described in a separate technical report.
Manhattan Project: Einstein's Letter, 1939
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 NaturalDukeWakefieldSulfate Reducing(Journalspectroscopy ofArticle)SciTechNorris Bradbury, RobertThe presidentEinstein's
Dipolar Bose-Einstein Condensate Dynamics in A Chaotic Potential
Moran, Roxanne Kimberly
2013-01-01
Smith, Bose-Einstein Condensates in Dilute Gases (CambridgeDipolar Bose-Einstein Condensate Dynamics in A ChaoticDipolar Bose-Einstein Condensate Dynamics in A Chaotic
Three Alumni Honored at Distinguished Alumni Awards Dinner in April
Simons, Jack
summer ahead of you as well! Sincerely, Cynthia J. Burrows Distinguished Professor and Chair Thatcher Presidential Endowed Chair of Biological Chemistry Dear Chemistry Friends and Families, Several women
Sandia Energy - Two CRF Papers Named "Distinguished" for 34th...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Two CRF Papers Named "Distinguished" for 34th International Symposium on Combustion Home Energy Transportation Energy CRF Facilities Partnership News News & Events Research &...
Distinguishing LSP archetypes via gluino pair production at LHC13...
Office of Scientific and Technical Information (OSTI)
Distinguishing LSP archetypes via gluino pair production at LHC13 Citation Details In-Document Search This content will become publicly available on August 19, 2016 Title:...
Conical Kähler–Einstein Metrics Revisited
2014-08-08
From now on in this paper, we assume X is a smooth Fano manifold, and D is a ... not unique, we can still identify the correct limit Kähler–Einstein metric in the moduli space. ... implies that there is no Kähler–Einstein metric on P2 which bends.
Exact Vacuum Solutions to the Einstein Equation
Ying-Qiu Gu
2007-06-17
In this paper, we present a framework for getting a series of exact vacuum solutions to the Einstein equation. This procedure of resolution is based on a canonical form of the metric. According to this procedure, the Einstein equation can be reduced to some 2-dimensional Laplace-like equations or rotation and divergence equations, which are much convenient for the resolution.
Lanier, Clinton David
1994-01-01
comes from the Greek word paradoxon with the roots para, which means "contrary to, " and doza, which means "opinion. " To state it simply, paradox is defined as a statement which is contrary to accepted opinion. This simple definition has evolved over... valuable and enduring lessons. "' In 1914, Camus's father was drafted into the French army and was killed in the first battle of the Marne. Camus's mother moved herself and her two sons, Lucien, the eldest, and Albert, to the working-class district...
New Integral Distinguisher for Rijndael-256 Yuechuan Wei1
International Association for Cryptologic Research (IACR)
New Integral Distinguisher for Rijndael-256 Yuechuan Wei1 , Bing Sun2 and Chao Li1,2,3 1 School, integral attack, Rijndael-256 1 Introduction The known integral distinguishers of Rijndael-256 are based the square property which is byte-oriented[15, 7]. For example, the known 3-round integral distin- guisher
A New Statistical Distinguisher for the Shrinking Generator
International Association for Cryptologic Research (IACR)
A New Statistical Distinguisher for the Shrinking Generator Jovan Dj. Goli#19;c and Renato Menicocci Abstract The shrinking generator is a well-known keystream generator composed of two linear for keystream generators are algorithms whose objective is to distinguish the keystream sequence from a purely
Einstein Gravity from Conformal Gravity
Juan Maldacena
2011-06-09
We show that that four dimensional conformal gravity plus a simple Neumann boundary condition can be used to get the semiclassical (or tree level) wavefunction of the universe of four dimensional asymptotically de-Sitter or Euclidean anti-de Sitter spacetimes. This simple Neumann boundary condition selects the Einstein solution out of the more numerous solutions of conformal gravity. It thus removes the ghosts of conformal gravity from this computation. In the case of a five dimensional pure gravity theory with a positive cosmological constant we show that the late time superhorizon tree level probability measure, $|\\Psi [ g ]|^2$, for its four dimensional spatial slices is given by the action of Euclidean four dimensional conformal gravity.
Quantum theory and Einstein's general relativity
v. Borzeszkowski, H.; Treder, H.
1982-11-01
We dicusss the meaning and prove the accordance of general relativity, wave mechanics, and the quantization of Einstein's gravitation equations themselves. Firstly, we have the problem of the influence of gravitational fields on the de Broglie waves, which influence is in accordance with Einstein's weak principle of equivalence and the limitation of measurements given by Heisenberg's uncertainty relations. Secondly, the quantization of the gravitational fields is a ''quantization of geometry.'' However, classical and quantum gravitation have the same physical meaning according to limitations of measurements given by Einstein's strong principle of equivalence and the Heisenberg uncertainties for the mechanics of test bodies.
REVIEW ARTICLE FOCUS BoseEinstein condensation in
Loss, Daniel
REVIEW ARTICLE FOCUS BoseEinstein condensation in magnetic insulators The BoseEinstein condensate-mail: thierry.giamarchi@physics.unige.ch; c.ruegg@ucl.ac.uk; olegt@jhu.edu Not long after Bose and Einstein . It is thus natural to ask whether these bosons can undergo Bose Einstein condensation and become superfluid
Quantum Physics at the `Einstein meets Magritte' conference
Aerts, Diederik
Quantum Physics at the `Einstein meets Magritte' conference Diederik Aerts Center Leo Apostel at the international conference 'Einstein meets Magritte'. The meeting between Einstein and Magritte represented: Aerts, D., 1996, "Quantum physics at the Einstein meets Magritte confer- ence", Int. J. Theor. Phys., 35
Stability of the Einstein static universe in Einstein-Cartan theory
Atazadeh, K., E-mail: atazadeh@azaruniv.ac.ir [Department of Physics, Azarbaijan Shahid Madani University, Tabriz, 53714-161 (Iran, Islamic Republic of)
2014-06-01
The existence and stability of the Einstein static solution have been built in the Einstein-Cartan gravity. We show that this solution in the presence of perfect fluid with spin density satisfying the Weyssenhoff restriction is cyclically stable around a center equilibrium point. Thus, study of this solution is interesting because it supports non-singular emergent cosmological models in which the early universe oscillates indeterminately about an initial Einstein static solution and is thus past eternal.
Davis, H. Floyd
A Low-Cost Quantitative Absorption Spectrophotometer Daniel R. Albert, Michael A. Todt, and H with spectrophotometry. Additionally, more than 75% of the high school teachers polled stated that the high cost of modern spectrophotometers was prohibitive for regular classroom use. The lowest-cost modern
Roald Sosnovskiy
2009-01-16
The cause of an infringement in GR of a gravitational field energy conservation law is investigated . The equation of a gravitational field not contradicting to the energy conservation law is suggested. This equation satisfy to the Einstein,s requirement of equivalence of all energy kinds as sources of a gravitational field. This equation is solved in paper for cosmic objects. It is showed, that results for some objects - for black holes and gravitating strings-essentialy differ from such for Einstein,s equation, have the symple meaning and do not contradictions.
Boundary conditions for the Einstein-Christoffel formulation of Einstein's equations
Douglas N. Arnold; Nicolae Tarfulea
2006-11-02
Specifying boundary conditions continues to be a challenge in numerical relativity in order to obtain a long time convergent numerical simulation of Einstein's equations in domains with artificial boundaries. In this paper, we address this problem for the Einstein--Christoffel (EC) symmetric hyperbolic formulation of Einstein's equations linearized around flat spacetime. First, we prescribe simple boundary conditions that make the problem well posed and preserve the constraints. Next, we indicate boundary conditions for a system that extends the linearized EC system by including the momentum constraints and whose solution solves Einstein's equations in a bounded domain.
Causality in scalar-Einstein waves
Mark D. Roberts
2015-03-13
A wavelike scalar-Einstein solution is found and indicating vectors constructed from the Bel-Robinson tensor are used to study which objects co-move with the wave and whether gravitational energy transfer is null.
Quantum reflection of Bose-Einstein Condensates
Pasquini, Thomas A., Jr
2007-01-01
Recent developments in atom optics have brought Bose-Einstein condensates within 1 pm of solid surfaces where the atom-surface interactions can no longer be ignored. At long- range, the atom-surface interaction is described ...
Einstein's Energy-Free Gravitational Field
Kenneth Dalton
1998-03-13
We show that Einstein's gravitational field has zero energy, momentum, and stress. This conclusion follows directly from the gravitational field equations, in conjunction with the differential law of energy-momentum conservation $ T^{\\mu\
Einstein's Biggest Blunder: A Cosmic Mystery Story
Krauss, Lawrence
2010-09-01
The standard model of cosmology built up over 20 years is no longer accepted as accurate. New data suggest that most of the energy density of the universe may be contained in empty space. Remarkably, this is exactly what would be expected if Einstein's cosmological constant really exists. If it does, its origin is the biggest mystery in physics and presents huge challenges for the fundamental theories of elementary particles and fields. Krauss explains Einstein's concept and describes its possible implications.
Einstein's Apple: His First Principle of Equivalence
Engelbert L. Schucking; Eugene J. Surowitz
2012-08-09
After a historical discussion of Einstein's 1907 principle of equivalence, a homogeneous gravitational field in Minkowski spacetime is constructed. It is pointed out that the reference frames in gravitational theory can be understood as spaces with a flat connection and torsion defined through teleparallelism. This kind of torsion was introduced by Einstein in 1928. The concept of torsion is discussed through simple examples and some historical observations.
2010 Society of Petroleum Engineers John Franklin Carll Distinguished
Zhou, Chongwu
Smart Oilfield Technologies (CiSofT) #12;Olin Hall 500 Los Angeles CA 90089-1451 http Distinguished Service Award in 2005 and the Technology Trans- fer Award for Development of the Smart Oilfield
Distinguishing exotic states from scattering states in lattice QCD
Sigaev, Dmitry
2008-01-01
This work explores the problem of distinguishing potentially interesting new exotic states in QCD from conventional scattering states using lattice QCD, and addresses the specific case of the search for localized resonances ...
Personality traits distinguishing dementia with Lewy bodies from Alzheimer disease
Galvin, James E.; Malcom, Heather; Johnson, David Kevin; Morris, John C.
2007-05-29
Personality traits distinguishing dementia with Lewy bodies from Alzheimer disease James E. Galvin, MD, MPH Heather Malcom David Johnson, PhD John C. Morris, MD ABSTRACT Objective: To identify personality traits that distinguish dementia with Lewy... and differentiation in conjunction with other DLB features. METHODS Research participants. Beginning in 1979, over 3,000 individuals have been enrolled in our longitudinal studies of healthy aging and dementia and over 800 of these participants have been studied...
Can accretion disk properties observationally distinguish black holes from naked singularities?
Z. Kovacs; T. Harko
2010-12-06
Naked singularities are hypothetical astrophysical objects, characterized by a gravitational singularity without an event horizon. Penrose has proposed a conjecture, according to which there exists a cosmic censor who forbids the occurrence of naked singularities. Distinguishing between astrophysical black holes and naked singularities is a major challenge for present day observational astronomy. A possibility of differentiating naked singularities from black holes is through the comparative study of thin accretion disks properties around rotating naked singularities and Kerr-type black holes, respectively. In the present paper, we consider accretion disks around rotating naked singularities, obtained as solutions of the field equations in the Einstein-massless scalar field theory. A first major difference between rotating naked singularities and Kerr black holes is in the frame dragging effect, the angular velocity of a rotating naked singularity being inversely proportional to its spin parameter. Due to the differences in the exterior geometry, the thermodynamic and electromagnetic properties of the disks are different for these two classes of compact objects, consequently giving clear observational signatures that could discriminate between black holes and naked singularities. For specific values of the spin parameter and of the scalar charge, the energy flux from the disk around a rotating naked singularity can exceed by several orders of magnitude the flux from the disk of a Kerr black hole. The conversion efficiency of the accreting mass into radiation by rotating naked singularities is always higher than the conversion efficiency for black holes. Thus, these observational signatures may provide the necessary tools from clearly distinguishing rotating naked singularities from Kerr-type black holes.
Rostock, Universität
Wolter,Lehrstuhl Strömungsmechanik, Universität Rostock Fr. 15.06.2012 10:30 Uhr Offshore Windkraft Niels
, ALBERT M. DAY, Director JUVENILE FORMS OF NEOTHUNNUS MACROPTERUS, KATSUWONUS PELAMIS AND EUTHYNNUS Y Al and Schlegel)__________________ 395 Katsuwonus pelamis (Linnaeus _ _ _ _ _ _ _ _ _ _ _ 404 #12;JUVENILE FORMS OF NEOTHUNNUS MACROPTERUS, KATSUWONUS PELAMIS, AND EUTHYNNUS YAlTO FROM
Einstein-Rosen "Bridge" Needs Lightlike Brane Source
Eduardo Guendelman; Alexander Kaganovich; Emil Nissimov; Svetlana Pacheva
2009-10-25
The Einstein-Rosen "bridge" wormhole solution proposed in the classic paper [1] does not satisfy the vacuum Einstein equations at the wormhole throat. We show that the fully consistent formulation of the original Einstein-Rosen "bridge" requires solving Einstein equations of bulk D=4 gravity coupled to a lightlike brane with a well-defined world-volume action. The non-vanishing contribution of Einstein-Rosen "bridge" solution to the right hand side of Einstein equations at the throat matches precisely the surface stress-energy tensor of the lightlike brane which automatically occupies the throat ("horizon straddling") - a feature triggered by the world-volume lightlike brane dynamics.
Proceedings of the 10th Patras Workshop On Axions,
Albert Einstein Center for Fundamental Physics University of Bern Sidlerstrasse 5 3012 Bern Switzerland
PHYSICAL REVIEW A 91, 022505 (2015) Spectroscopy of Ba and Ba+
Gratta, Giorgio
2015-01-01
, Albert Einstein Center for Fundamental Physics, University of Bern, CH-3012 Bern, Switzerland 16 Lawrence
Multi-Photon Interference and Temporal Distinguishability of Photons
Z. Y. Ou
2007-08-24
A number of recent interference experiments involving multiple photons are reviewed. These experiments include generalized photon bunching effects, generalized Hong-Ou-Mandel interference effects and multi-photon interferometry for demonstrations of multi-photon de Broglie wavelength. The multi-photon states used in these experiments are from two pairs of photons in parametric down-conversion. We find that the size of the interference effect in these experiments, characterized by the visibility of interference pattern, is governed by the degree of distinguishability among different pairs of photons. Based on this discovery, we generalize the concept of multi-photon temporal distinguishability and relate it to a number of multi-photon interference effects. Finally, we make an attempt to interpret the coherence theory by the multi-photon interference via the concept of temporal distinguishability of photons.
Understanding entanglement as resource: locally distinguishing unextendible product bases
Scott M. Cohen
2008-01-08
It is known that the states in an unextendible product basis (UPB) cannot be distinguished perfectly when the parties are restricted to local operations and classical communication (LOCC). Previous discussions of such bases have left open the following question: What entanglement resources are necessary and/or sufficient for this task to be possible with LOCC? In this paper, I present protocols which use entanglement more efficiently than teleportation to distinguish certain classes of UPB's. The ideas underlying my approach to this problem offer rather general insight into why entanglement is useful for such tasks.
Emergent Properties of the Bose-Einstein-Hubbard Condensate in...
Office of Scientific and Technical Information (OSTI)
Technical Report: Emergent Properties of the Bose-Einstein-Hubbard Condensate in UO2(+x) Citation Details In-Document Search Title: Emergent Properties of the Bose-Einstein-Hubbard...
Miya Tokumitsu
2006-01-01
artists (Jan de Bisschop, Constantijn Huygens the Younger) in seventeenth- century Holland. This practice parallels the vogue for outdoor paintings by gentlemen in England and reminds us about Rembrandt?s social aspirations as well as his informal, non... Paintings: Rembrandt, Van Beke, Vermeer and Others. Zwolle: Waanders Publishers, 2004. 352 pp. + 302 illus. $90.00. Review by MIYA TOKUMITSU, UNIVERSITY OF PENNSYLVANIA. Reading Albert Blankert?s Selected Writings on Dutch Painting: Rembrandt, Van Beke...
2011 Robert Stewart Distinguished Lecture ALL SCIENCE IS COMPUTER SCIENCE
Mayfield, John
2011 Robert Stewart Distinguished Lecture ALL SCIENCE IS COMPUTER SCIENCE Alfred Aho, Columbia in the Computer Science Department at Columbia University. He served as Chair of the department from 1995 to 1997.D. in Electrical Engineering/Computer Science from Princeton University. Professor Aho won the Great Teacher Award
Cardiff University Distinguished Lecture Symposium Advances in Solar Energy
Martin, Ralph R.
Cardiff University Distinguished Lecture Symposium Advances in Solar Energy Thursday 22nd March prospects for inorganic thin film photovoltaic solar cells for large scale energy generation 2:55 Dr Emyr:50 Professor James Durrant (Imperial College London, England) Photochemical approaches to solar energy
Routing for Wireless Multi Hop Networks Unifying and Distinguishing Features
Graham, Nick
-to-end communication, wireless communication provides flexible deployment and use, cost reduction, mobility, network dynamic network conditions due to interference, loss of signal power with distance and freedom of mobilityRouting for Wireless Multi Hop Networks Unifying and Distinguishing Features Technical Report
ROBERT E. MARC, PHD Distinguished Professor of Ophthalmology
Marc, Robert E.
ROBERT E. MARC, PHD Distinguished Professor of Ophthalmology University of Utah School of Medicine, Salt Lake City, UT 84132 robert.marc@hsc.utah.edu (801) 585-6500 EDUCATION 1971 BSc Honors, Univ Texas (Science, Nature, PNAS, PLoS Biology) SELECTED PUBLICATIONS Marc et al. 2012 Building retinal connectomes
NREL Today: Symposium and Distinguished Ecosystem Ecologist Lecture and Awards
MacDonald, Lee
NREL Today: Symposium and Distinguished Ecosystem Ecologist Lecture and Awards Thursday, November Student Center For more information about the event, visit http://www.nrel.colostate.edu/ecosystem-award.html or email Laurie.Richards@colostate.edu. NREL Today: Symposium Program 1:00-1:05 Introduction from Director
Lynn Wecker, PhD Distinguished Professor, Psychiatry and
Meyers, Steven D.
A Addiction Lynn Wecker, PhD Distinguished Professor, Psychiatry and Pharmacology & Molecular of Pediatrics Adolescent Health Carol Bryant, PhD Professor and Co-director Florida Prevention Research Center Professor of Pediatrics Expertise: General adolescent medicine Ellen Daley, PhD Assistant Research Professor
BoseEinstein condensation of excitons in bilayer electron systems
Eisenstein, Jim
BoseEinstein condensation of excitons in bilayer electron systems J. P. Eisenstein1 * & A. H. Mac is represented by a wave that has both amplitude and phase. The most remarkable consequence of BoseEinstein cousins, any number of bosons can crowd into the same microscopic state. Indeed, Einstein predicted
Passing the Einstein-Rosen bridge
M. O. Katanaev
2013-10-28
We relax the requirement of geodesic completeness of a space-time. Instead, we require test particles trajectories to be smooth only in the physical sector. Test particles trajectories for Einstein--Rosen bridge are proved to be smooth in the physical sector, and particles can freely penetrate the bridge in both directions.
On algebraic endomorphisms of the Einstein gyrogroup
Lajos Molnár; Dániel Virosztek
2015-06-20
We describe the structure of all continuous algebraic endomorphisms of the open unit ball $\\mathbf{B}$ of $\\mathbb{R}^3$ equipped with the Einstein velocity addition. We show that any nonzero such transformation originates from an orthogonal linear transformation on $\\mathbb{R}^3$.
General proof of entropy principle in Einstein-Maxwell theory
Fang, Xiongjun
2015-01-01
We consider a static self-gravitating charged perfect fluid system in the Einstein-Maxwell theory. Assume Maxwell's equation and the Einstein constraint equation are satisfied, and the temperature of the fluid obeys Tolman's law. Then we prove that the total entropy of the fluid achieves an extremum implies other components of Einstein's equation for any variations of metric and electrical potential with fixed boundary values. Conversely, if Einstein's equation and Maxwell's equations hold, the total entropy achieves an extremum. Our work suggests that the maximum entropy principle is consistent with Einstein's equation when electric field is taken into account.
The Mythical Snake which Swallows its Tail: Einstein's matter world
Weinstein, Galina
2013-01-01
In 1917 Einstein introduced into his field equations a cosmological term having the cosmological constant as a coefficient, in order that the theory should yield a static universe. Einstein desired to eliminate absolute space from physics according to "Mach's ideas". De Sitter objected to the "world-matter" in Einstein's world, and proposed a vacuum solution of Einstein's field equations with the cosmological constant and with no "world-matter". In 1920 the world-matter of Einstein's world was equivalent to "Mach's Ether", a carrier of the effects of inertia. De Sitter's 1917 solution predicted a spectral shift effect. In 1923 Eddington and Weyl adopted De Sitter's model and studied this effect. Einstein objected to this "cosmological problem". This paper is a new interpretation to Einstein's cosmological considerations over the period 1917-1923.
Visibility bound caused by a distinguishable noise particle
Miroslav Gavenda; Lucie Celechovska; Jan Soubusta; Miloslav Dusek; Radim Filip
2011-03-11
We investigate how distinguishability of a "noise" particle degrades interference of the "signal" particle. The signal, represented by an equatorial state of a photonic qubit, is mixed with noise, represented by another photonic qubit, via linear coupling on the beam splitter. We report on the degradation of the "signal" photon interference depending on the degree of indistinguishability between "signal" and "noise" photon. When the photons are principally completely distinguishable but technically indistinguishable the visibility drops to the value 1/sqrt(2). As the photons become more indistinguishable the maximal visibility increases and reaches the unit value for completely indistinguishable photons. We have examined this effect experimentally using setup with fiber optics two-photon Mach-Zehnder interferometer.
Axions: Bose Einstein Condensate or Classical Field?
Sacha Davidson
2014-12-20
The axion is a motivated dark matter candidate, so it would be interesting to find features in Large Scale Structures specific to axion dark matter. Such features were proposed for a Bose Einstein condensate of axions, leading to confusion in the literature (to which I contributed) about whether axions condense due to their gravitational interactions. This note argues that the Bose Einstein condensation of axions is a red herring: the axion dark matter produced by the misalignment mechanism is already a classical field, which has the distinctive features attributed to the axion condensate (BE condensates are described as classical fields). This note also estimates that the rate at which axion particles condense to the field, or the field evaporates to particles, is negligeable.
Riemann-Liouville Fractional Einstein Field Equations
Joakim Munkhammar
2010-03-18
In this paper we establish a fractional generalization of Einstein field equations based on the Riemann-Liouville fractional generalization of the ordinary differential operator $\\partial_\\mu$. We show some elementary properties and prove that the field equations correspond to the regular Einstein field equations for the fractional order $\\alpha = 1$. In addition to this we show that the field theory is inherently non-local in this approach. We also derive the linear field equations and show that they are a generalized version of the time fractional diffusion-wave equation. We show that in the Newtonian limit a fractional version of Poisson's equation for gravity arises. Finally we conclude open problems such as the relation of the non-locality of this theory to quantum field theories and the possible relation to fractional mechanics.
The Geroch group in Einstein spaces
Robert G. Leigh; Anastasios C. Petkou; P. Marios Petropoulos; Prasanta K. Tripathy
2015-06-17
Geroch's solution-generating method is extended to the case of Einstein spaces, which possess a Killing vector {{}and are thus asymptotically (locally) (anti-)de Sitter}. This includes the reduction to a three-dimensional coset space, the description of the dynamics in terms of a sigma-model and its transformation properties under the $SL(2,\\mathbb{R})$ group, and the reconstruction of new four-dimensional Einstein spaces. The detailed analysis of the space of solutions is performed using the Hamilton--Jacobi method in the instance where the three-dimensional coset space is conformal to $\\mathbb{R}\\times \\mathcal{S}_2$. The cosmological constant appears in this framework as a constant of motion and transforms under $SL(2,\\mathbb{R})$.
Fast transport of Bose-Einstein condensates
E. Torrontegui; Xi Chen; M. Modugno; S. Schmidt; A. Ruschhaupt; J. G. Muga
2011-03-13
We propose an inverse method to accelerate without final excitation the adiabatic transport of a Bose Einstein condensate. The method, applicable to arbitrary potential traps, is based on a partial extension of the Lewis-Riesenfeld invariants, and provides transport protocols that satisfy exactly the no-excitation conditions without constraints or approximations. This inverse method is complemented by optimizing the trap trajectory with respect to different physical criteria and by studying the effect of noise.
Time Reversal of Bose-Einstein Condensates
Martin, J.; Georgeot, B.; Shepelyansky, D. L. [Laboratoire de Physique Theorique, Universite de Toulouse III, CNRS, 31062 Toulouse (France)
2008-08-15
Using Gross-Pitaevskii equation, we study the time reversibility of Bose-Einstein condensates (BEC) in kicked optical lattices, showing that in the regime of quantum chaos, the dynamics can be inverted from explosion to collapse. The accuracy of time reversal decreases with the increase of atom interactions in BEC, until it is completely lost. Surprisingly, quantum chaos helps to restore time reversibility. These predictions can be tested with existing experimental setups.
The Semiclassical Einstein Equation on Cosmological Spacetimes
Daniel Siemssen
2015-03-06
The subject of this thesis is the coupling of quantum fields to a classical gravitational background in a semiclassical fashion. It contains a thorough introduction into quantum field theory on curved spacetime with a focus on the stress-energy tensor and the semiclassical Einstein equation. Basic notions of differential geometry, topology, functional and microlocal analysis, causality and general relativity will be summarised, and the algebraic approach to QFT on curved spacetime will be reviewed. Apart from these foundations, the original research of the author and his collaborators will be presented: Together with Fewster, the author studied the up and down structure of permutations using their decomposition into so-called atomic permutations. The relevance of these results to this thesis is their application in the calculation of the moments of quadratic quantum fields. In a work with Pinamonti, the author showed the local and global existence of solutions to the semiclassical Einstein equation in flat cosmological spacetimes coupled to a scalar field by solving simultaneously for the quantum state and the Hubble function in an integral-functional equation. The theorem is proved with a fixed-point theorem using the continuous functional differentiability and boundedness of the integral kernel of the integral-functional equation. In another work with Pinamonti the author proposed an extension of the semiclassical Einstein equations which couples the moments of a stochastic Einstein tensor to the moments of the quantum stress-energy tensor. In a toy model of a Newtonianly perturbed exponentially expanding spacetime it is shown that the quantum fluctuations of the stress-energy tensor induce an almost scale-invariant power spectrum for the perturbation potential and that non-Gaussianties arise naturally.
Distinguishing Off-Shell Supergravities With On-Shell Physics
Neil D. Lambert; Gregory W. Moore
2005-10-04
We show that it is possible to distinguish between different off-shell completions of supergravity at the on-shell level. We focus on the comparison of the ``new minimal'' formulation of off-shell four-dimensional N=1 supergravity with the ``old minimal'' formulation. We show that there are 3-manifolds which admit supersymmetric compactifications in the new-minimal formulation but which do not admit supersymmetric compactifications in other formulations. Moreover, on manifolds with boundary the new-minimal formulation admits ``singleton modes'' which are absent in other formulations.
Shrestha, Uttam; Ruostekoski, Janne
2012-01-01
atomic Bose–Einstein condensates (BECs) exhibit notablyspecies Bose–Einstein condensate in an optical lattice Uttamspecies Bose–Einstein condensate to an optical lattice in a
JLab, Hampton U. celebrate Einstein's love of music with special...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
available from Jack Liebeck's website JLab, Hampton U. celebrate Einstein's love of music with special event at CNU's Ferguson Center for the Arts April 11, 2005 The Department...
Spatial structure of a collisionally inhomogeneous Bose-Einstein...
Office of Scientific and Technical Information (OSTI)
Spatial structure of a collisionally inhomogeneous Bose-Einstein condensate Citation Details In-Document Search Title: Spatial structure of a collisionally inhomogeneous...
Bose-Einstein Condensate general relativistic stars
P. H. Chavanis; T. Harko
2011-08-19
We analyze the possibility that due to their superfluid properties some compact astrophysical objects may contain a significant part of their matter in the form of a Bose-Einstein condensate. To study the condensate we use the Gross-Pitaevskii equation, with arbitrary non-linearity. By introducing the Madelung representation of the wave function, we formulate the dynamics of the system in terms of the continuity equation and of the hydrodynamic Euler equations. The non-relativistic and Newtonian Bose-Einstein gravitational condensate can be described as a gas, whose density and pressure are related by a barotropic equation of state. In the case of a condensate with quartic non-linearity, the equation of state is polytropic with index one. In the framework of the Thomas-Fermi approximation the structure of the Newtonian gravitational condensate is described by the Lane-Emden equation, which can be exactly solved. The case of the rotating condensate is also discussed. General relativistic configurations with quartic non-linearity are studied numerically with both non-relativistic and relativistic equations of state, and the maximum mass of the stable configuration is determined. Condensates with particle masses of the order of two neutron masses (Cooper pair) and scattering length of the order of 10-20 fm have maximum masses of the order of 2 M_sun, maximum central density of the order of 0.1-0.3 10^16 g/cm^3 and minimum radii in the range of 10-20 km. In this way we obtain a large class of stable astrophysical objects, whose basic astrophysical parameters (mass and radius) sensitively depend on the mass of the condensed particle, and on the scattering length. We also propose that the recently observed neutron stars with masses in the range of 2-2.4 M_sun are Bose-Einstein Condensate stars.
Distinguishing Spins in Decay Chains at the Large Hadron Collider
Christiana Athanasiou; Christopher G. Lester; Jennifer M. Smillie; Bryan R. Webber
2008-08-29
If new particles are discovered at the LHC, it will be important to determine their spins in as model-independent a way as possible. We consider the case, commonly encountered in models of physics beyond the Standard Model, of a new scalar or fermion $D$ decaying sequentially into other new particles $C,B,A$ via the decay chain $D\\to C q$, $C\\to B l^{near}$, $B\\to A l^{far}$, $l^{near}$ and $l^{far}$ being opposite-sign same-flavour charged leptons and $A$ being invisible. We compute the observable 2- and 3-particle invariant mass distributions for all possible spin assignments of the new particles, and discuss their distinguishability using a quantitative measure known as the Kullback-Leibler distance.
Shih, Albert J.
of the temperature distribution on the cavity wall surface in diesel exhaust aftertreatment filters usingABSTRACT KONG, JIAN. Infrared-Based Temperature Measurement in Ceramics Grinding and Diesel Exhaust Aftertreatment Filters. (Under the direction of Albert J. Shih) Non-contact remote-sensing radiation thermometry
Reed, Christopher A.
Chemistry and Engineering News Volume 90 Issue 7 | February 13, 2012 | pp. 48-49 | Awards F. Albert, "which are so electrophilic that they extract hydride from alkanes at 40 °C to form stable carbenium. Chemical & Engineering News ISSN 0009-2347 Copyright © 2012 American Chemical Society #12;
Newton to Einstein — dust to dust
Kopp, Michael; Uhlemann, Cora; Haugg, Thomas E-mail: cora.uhlemann@physik.lmu.de
2014-03-01
We investigate the relation between the standard Newtonian equations for a pressureless fluid (dust) and the Einstein equations in a double expansion in small scales and small metric perturbations. We find that parts of the Einstein equations can be rewritten as a closed system of two coupled differential equations for the scalar and transverse vector metric perturbations in Poisson gauge. It is then shown that this system is equivalent to the Newtonian system of continuity and Euler equations. Brustein and Riotto (2011) conjectured the equivalence of these systems in the special case where vector perturbations were neglected. We show that this approach does not lead to the Euler equation but to a physically different one with large deviations already in the 1-loop power spectrum. We show that it is also possible to consistently set to zero the vector perturbations which strongly constrains the allowed initial conditions, in particular excluding Gaussian ones such that inclusion of vector perturbations is inevitable in the cosmological context. In addition we derive nonlinear equations for the gravitational slip and tensor perturbations, thereby extending Newtonian gravity of a dust fluid to account for nonlinear light propagation effects and dust-induced gravitational waves.
Static self-gravitating elastic bodies in Einstein gravity
Lars Andersson; Robert Beig; Bernd Schmidt
2009-01-12
We prove that given a stress-free elastic body there exists, for sufficiently small values of the gravitational constant, a unique static solution of the Einstein equations coupled to the equations of relativistic elasticity. The solution constructed is a small deformation of the relaxed configuration. This result yields the first proof of existence of static solutions of the Einstein equations without symmetries.
An alternative derivation of Einstein's Doppler shift and aberration formulae
Jean Reignier
2009-02-06
I propose an alternative, purely kinematical, derivation of Einstein's Doppler formula. It is valid for periodic signals of any shape that propagate with the velocity of light. The formula is asymptotic in a parameter proportional to the relative variation of the distance source-receiver during one period. As a by-product, I also derive an alternative proof of Einstein's aberration formulae.
Non-commutative Einstein-Proca Space-time
Blanca Gónzales; Román Linares; Marco Maceda; Oscar Sánchez-Santos
2014-09-12
In this work we present a deformed model of Einstein-Proca space-time based on the replacement of point-like sources by non-commutative smeared distributions. We discuss the solutions to the set of non-commutative Einstein-Proca equations thus obtained, with emphasis on the issue of singularities and horizons.
Energy in the Einstein-Aether Theory
Christopher Eling
2009-12-06
We investigate the energy of a theory with a unit vector field (the "aether") coupled to gravity. Both the Weinberg and Einstein type energy-momentum pseudotensors are employed. In the linearized theory we find expressions for the energy density of the 5 wave modes. The requirement that the modes have positive energy is then used to constrain the theory. In the fully non-linear theory we compute the total energy of an asymptotically flat spacetime. The resulting energy expression is modified by the presence of the aether due to the non-zero value of the unit vector at infinity and its 1/r falloff. The question of non-linear energy positivity is also discussed, but not resolved.
Nonlinear interferometry with Bose-Einstein condensates
Tacla, Alexandre B. [Center for Quantum Information and Control, MSC 07-4220, University of New Mexico, Albuquerque, New Mexico 87131-0001 (United States); Boixo, Sergio [Institute for Quantum Information, California Institute of Technology, Pasadena, California 91125 (United States); Datta, Animesh [Clarendon Laboratory, Department of Physics, University of Oxford, OX1 3PU (United Kingdom); Shaji, Anil [School of Physics, Indian Institute of Science Education and Research, College of Engineering Trivandrum Campus, Thiruvananthapuram, Kerala 695016 (India); Caves, Carlton M. [Center for Quantum Information and Control, MSC 07-4220, University of New Mexico, Albuquerque, New Mexico 87131-0001 (United States); School of Mathematics and Physics, University of Queensland, Brisbane, Queensland 4072 (Australia)
2010-11-15
We analyze a proposed experiment [Boixo et al., Phys. Rev. Lett. 101, 040403 (2008)] for achieving sensitivity scaling better than 1/N in a nonlinear Ramsey interferometer that uses a two-mode Bose-Einstein condensate (BEC) of N atoms. We present numerical simulations that confirm the analytical predictions for the effect of the spreading of the BEC ground-state wave function on the ideal 1/N{sup 3/2} scaling. Numerical integration of the coupled, time-dependent, two-mode Gross-Pitaevskii equations allows us to study the several simplifying assumptions made in the initial analytic study of the proposal and to explore when they can be justified. In particular, we find that the two modes share the same spatial wave function for a length of time that is sufficient to run the metrology scheme.
Neutron stars in Einstein-aether theory
Christopher Eling; Ted Jacobson; M. Coleman Miller
2009-12-06
As current and future experiments probe strong gravitational regimes around neutron stars and black holes, it is desirable to have theoretically sound alternatives to general relativity against which to test observations. Here we study the consequences of one such generalization, Einstein-aether theory, for the properties of non-rotating neutron stars. This theory has a parameter range that satisfies all current weak-field tests. We find that within this range it leads to lower maximum neutron star masses, as well as larger surface redshifts at a particular mass, for a given nuclear equation of state. For non-rotating black holes and neutron stars, the innermost stable circular orbit is only slightly modified in this theory.
Champion, Elke Lorenz
1998-01-01
Die Aufgabe dieser Arbeit besteht darin, Sidonie Na?dherny? Einfluß auf das Werk von Karl Kraus, vor allem auf seine Lyrik, an Hand der Albert Bloch/Sidonie Na?dherny?-Korrespondenz auszuwerten. Neben den eigentlichen ...
The magnetic dipole interaction in Einstein-Maxwell theory
W. B. Bonnor
2002-03-13
I derive an exact, static, axially symmetric solution of the Einstein-Maxwell equations representing two massless magnetic dipoles, and compare it with the corresponding solution of Einstein's equations for two massless spinning particles (see gr-qc/0201094). I then obtain an exact stationary solution of the Einstein-Maxwell equations representing two massless spinning magnets in balance. The conclusion is that the spin-spin force is analogous to the force between two magnetic dipoles, but of opposite sign, and that the latter agrees with the classical value in the first approximation.
Back-reaction of Quantum fields in an Einstein Universe
M. B. Altaie
2001-04-30
We study the back-reaction effects of the finite-temperature scalar field and the photon field in the background of an Einstein universe. In each case we find a relation between the temperature of the universe and its radius. These relations exhibit a minimum radius below which no self-consistent solution for the Einstein field equation can be found. A maximum temperature marks the transition from the vacuum dominated era to the radiation dominated era. An interpretation to this behavior in terms of Bose-Einstein condensation in the case of the scalar field is given.
Bose-Einstein condensates of polaritons: Vortices and superfluidity...
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Bose-Einstein condensates of polaritons: Vortices and superfluidity May 10, 2011 at 3:00PM36-428 Benoit Deveaud-Pldran Ecole Polytechnique Fdrale de Lausanne abstract: The...
La Relativit, Einstein e la Fisica del `900
Santorelli, Pietro
ascensori di Einstein CEINGE 14 Nov 2008 #12;g Ascensore in caduta libera Ascensore nello spazio remoto La fisica è la stessa CEINGE 14 Nov 2008 #12;g Ascensore in moto accelerato Ascensore sospeso alla fune
Realization of Bose-Einstein condensation with Lithium-7 atoms
Yu, Yichao
2014-01-01
This thesis presents our work on developing and improving the techniques of trapping and cooling an ultra-cold cloud of Lithium-7 atoms and the realization of the Bose- Einstein condensate as a first step to study quantum ...
Breakdown of Stokes-Einstein relation in supercooled water
Pradeep Kumar
2007-02-06
Water displays breakdown of the Stokes-Einstein relation at low temperatures. We hypothesize that the breakdown is a result of the structural changes and a sharp rise in dynamic heterogeneities that occurs low T upon crossing the Widom line.
Induced Matter Brane Gravity and Einstein Static Universe
Y. Heydarzade; F. Darabi
2015-04-21
We investigate stability of the Einstein static universe against the scalar, vector and tensor perturbations in the context of induced matter brane gravity. It is shown that in the framework of this model, the Einstein static universe has a positive spatial curvature. In contrast to the classical general relativity, it is found that a stable Einstein static universe against the scalar perturbations does exist provided that the variation of time dependent geometrical equation of state parameter is proportional to the minus of the variation of the scale factor, $\\delta \\omega_{g}(t)=-C\\delta a(t)$. We obtain neutral stability against the vector perturbations, and the stability against the tensor perturbations is guaranteed due to the positivity of the spatial curvature of the Einstein static universe in induced matter brane gravity.
Controlling phase separation of binary Bose-Einstein condensates...
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resonance We investigate controlled phase separation of a binary Bose-Einstein condensate in the proximity of a mixed-spin-channel Feshbach resonance in the |F1,msub F+1>...
Effects of interaction in Bose-Einstein condensates
Xu, Kaiwen
2006-01-01
This thesis discusses a series of studies that investigate the effects of interaction - essentially the s-wave scattering - in the various properties of Bose-Einstein condensates (BEC). The phonon wavefunction in a BEC was ...
Topography of FUS pathology distinguishes late-onset BIBD from aFTLD-U
2013-01-01
as: Lee et al. : Topography of FUS pathology distinguishesRESEARCH Open Access Topography of FUS pathologyregions. Conclusions: The topography of FUS pathology in
Three-dimensional hippocampal atrophy maps distinguish two common temporal lobe
Thompson, Paul
Three-dimensional hippocampal atrophy maps distinguish two common temporal lobe seizure ictal onset patterns (Engel, 1990). Hyper- synchronous (HYP) onsets consist of long-lasting (>5-s
Mercury dimer spectroscopy and an Einstein-Podolsky-Rosen experiment
Qu, Xinmei
2009-05-15
SPECTROSCOPY AND AN EINSTEIN-PODOLSKY-ROSEN EXPERIMENT A Dissertation by XINMEI QU Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY... August 2008 Major Subject: Physics MERCURY DIMER SPECTROSCOPY AND AN EINSTEIN-PODOLSKY-ROSEN EXPERIMENT A Dissertation by XINMEI QU Submitted to the Office of Graduate Studies of Texas A&M University in partial...
Integral Distinguishers for Reduced-round Riham AlTawy and Amr M. Youssef
International Association for Cryptologic Research (IACR)
Integral Distinguishers for Reduced-round Stribog Riham AlTawy and Amr M. Youssef Concordia as an asymmetric reply to the new SHA-3 selected by NIST. In this paper we investigate the structural integral, we present a forward and backward higher order integrals that can be used to distinguish 4 and 3
Distinguishing Attacks on MAC/HMAC Based on A New Dedicated Compression Function
International Association for Cryptologic Research (IACR)
Distinguishing Attacks on MAC/HMAC Based on A New Dedicated Compression Function Framework Zheng@mail.tsinghua.edu.cn Abstract. A new distinguishing attack on HMAC and NMAC based on a dedicated compression function framework. In ChinaCrypt2008, a new dedicated compression function framework (i.e. hash function H) and two
Einstein static Universe in non-minimal kinetic coupled gravity
K. Atazadeh; F. Darabi
2015-04-18
We study the stability of Einstein static Universe, with FLRW metric, by considering linear homogeneous perturbations in the kinetic coupled gravity. By taking linear homogeneous perturbations, we find that the stability of Einstein static Universe, in the kinetic coupled gravity with quadratic scalar field potential, for closed ($K=1$) isotropic and homogeneous FLRW Universe depends on the coupling parameters $\\kappa$ and $\\varepsilon$. Specifically, for $\\kappa=L_P^2$ and $\\varepsilon=1$ we find that the stability condition imposes the inequality $a_0>\\sqrt{3}L_P$ on the initial size $a_0$ of the closed Einstein static Universe before the inflation. Such inequality asserts that the initial size of the Einstein static Universe must be greater than the Planck length $L_P$, in consistency with the quantum gravity and quantum cosmology requirements. In this way, we have determined the non-minimal coupling parameter $\\kappa$ in the context of Einstein static Universe. Such a very small parameter is favored in the inflationary models constructed in the kinetic coupled gravity. We have also studied the stability against the vector and tensor perturbations and discussed on the acceptable values of the equation of state parameter.
Shrestha, Uttam; Ruostekoski, Janne
2012-01-01
Two-species atomic Bose–Einstein condensates (BECs) exhibitof a two-species Bose–Einstein condensate in an opticalof a two-species Bose–Einstein condensate to an optical
Weatherall, James; Search, Christopher; Jääskeläinen, Markku
2008-01-01
double-well Bose-Einstein condensate James Owen Weatherall,atomic Bose-Einstein condensate ?BEC? trapped in a double-and atomic Bose-Einstein condensates ?BEC’s? ?7?, and is now
Emergent quantum phases in a heteronuclear molecular Bose--Einstein condensate model
Melissa Duncan; Angela Foerster; Jon Links; Eduardo Mattei; Norman Oelkers; Arlei Prestes Tonel
2006-10-30
We study a three-mode Hamiltonian modelling a heteronuclear molecular Bose--Einstein condensate. Two modes are associated with two distinguishable atomic constituents, which can combine to form a molecule represented by the third mode. Beginning with a semi-classical analogue of the model, we conduct an analysis to determine the phase space fixed points of the system. Bifurcations of the fixed points naturally separate the coupling parameter space into different regions. Two distinct scenarios are found, dependent on whether the imbalance between the number operators for the atomic modes is zero or non-zero. This result suggests the ground-state properties of the model exhibit an unusual sensitivity on the atomic imbalance. We then test this finding for the quantum mechanical model. Specifically we use Bethe ansatz methods, ground-state expectation values, the character of the quantum dynamics, and ground-state wavefunction overlaps to clarify the nature of the ground-state phases. The character of the transition is smoothed due to quantum fluctuations, but we may nonetheless identify the emergence of a quantum phase boundary in the limit of zero atomic imbalance.
On the Einstein-Cartan cosmology vs. Planck data
Palle, Davor
2014-01-01
The first comprehensive analyses of Planck data reveal that the cosmological model with dark energy and cold dark matter can satisfactorily explain the essential physical features of the expanding Universe. However, the inability to simultaneously fit large and small scale TT power spectrum, scalar power index smaller than one and the observations of the violation of the isotropy found by few statistical indicators of the CMB, urge theorists to search for explanations. We show that the model of the Einstein-Cartan cosmology with clustered dark matter halos and their corresponding clustered angular momenta coupled to torsion, can account for small scale - large scale discrepancy and larger peculiar velocities (bulk flows) for galaxy clusters. The nonvanishing total angular momentum (torsion) of the Universe enters as a negative effective density term in the Einstein-Cartan equations causing partial cancellation of the mass density. The integrated Sachs-Wolfe contribution of the Einstein-Cartan model is negativ...
Modelling Bose Einstein Correlations via Elementary Emitting Cells
Oleg Utyuzh; Grzegorz Wilk; Zbigniew Wlodarczyk
2007-04-24
We propose a method of numerical modeling Bose Einstein Correlations by using the notion of Elementary Emitting Cells (EEC). They are intermediary objects containing identical bosons and are supposed to be produced independently during the hadronization process. Only bosons in EEC, which represents a single quantum state here, are subjected to the effects of Bose-Einstein (BE) statistics, which forces them to follow a geometrical distribution. There are no such effects between particles from different EECs. We illustrate our proposition by calculating a representative number of typical distributions and discussing their sensitivity to EECs and their characteristics.
Einstein as armchair detective: The case of stimulated radiation
Vasant Natarajan
2013-07-03
Einstein was in many ways like a detective on a mystery trail, though in his case he was on the trail of nature's mysteries and not some murder mystery! And like all good detectives he had a style. It consisted of taking facts that he knew were correct and forcing nature into a situation that would contradict this established truth. In this process she would be forced to reveal some new truths. Einstein's 1917 paper on the quantum theory of radiation is a classic example of this style and enabled him to predict the existence of stimulated radiation starting from an analysis of thermodynamic equilibrium between matter and radiation.
The Einstein static universe in Scalar-Fluid theories
Boehmer, Christian G; Wright, Matthew
2015-01-01
A new Lagrangian framework has recently been proposed to describe interactions between relativistic perfect fluids and scalar fields. In this paper we investigate the Einstein static universe in this new class of theories, which have been named Scalar-Fluid theories. The stability of the static solutions to both homogeneous and inhomogeneous perturbations is analysed deriving the relevant cosmological perturbation equations at the linear order. We can find several configurations corresponding to an Einstein static universes which are stable against inhomogeneous perturbations, but unstable against homogeneous perturbations. This shows the possible applications of Scalar-Fluid theories to the inflationary emergent universe scenario.
Detection of acceleration radiation in a Bose-Einstein condensate
A. Retzker; J. I. Cirac; M. B. Plenio; B. Reznik
2007-09-22
We propose and study methods for detecting the Unruh effect in a Bose-Einstein condensate. The Bogoliubov vacuum of a Bose-Einstein condensate is used here to simulate a scalar field-theory, and accelerated atom dots or optical lattices as means for detecting phonon radiation due to acceleration effects. We study Unruh's effect for linear acceleration and circular acceleration. In particular, we study the dispersive effects of the Bogoliubov spectrum on the ideal case of exact thermalization. Our results suggest that Unruh's acceleration radiation can be tested using current accessible experimental methods.
BoseEinstein Condensation in the Large Deviations Regime with Applications to Information
Merhav, Neri
BoseEinstein Condensation in the Large Deviations Regime with Applications to Information System(U) = lim M " - 1 M log Pr ( X i ni MU )# may exhibit phase transitions BoseEinstein condensation (BEC
??Rubidium Bose-Einstein condensates : machine construction and quantum Zeno experiments
Streed, Erik William
2006-01-01
This thesis details construction of a new apparatus for the production of 87Rb Bose-Einstein condensates and a subsequent quantum Zeno effect experiment. An experimental apparatus for producing large Bose-Einstein condensates ...
Distinguishing mixed quantum states: Minimum-error discrimination versus optimum unambiguous discrimination Ulrike Herzog1, * and János A. Bergou2 1 Institut für Physik, Humboldt-Universität zu Berlin 2004) We consider two different optimized measurement strategies for the discrimination
Sorghum Ergot: Distinguishing Sphacelia and Sclerotia of Claviceps africana in Seed
Frederickson, Debra; Odvody, Gary; Isakeit, Thomas
1999-07-05
. Sclerotia are ?resting? or dormancy structures equipped to withstand degradation by the L-5315 6-99 Sorghum Ergot Distinguishing Sphacelia and Sclerotia of Claviceps africana in Seed Debra E. Frederickson and Gary N. Odvody Assisted by Thomas Isakeit...
Paris-Sud XI, Université de
Information Systems-- Animations Artificial, augmented, and virtual realities Keywords: Human Motions performing various interactions in VE. Animating virtual humans to perform these tasks involves taking manyCan We Distinguish Biological Motions of Virtual Humans? Perceptual Study With Captured Motions
Debashish Chowdhury
2012-03-14
Molecular machines consist of either a single protein or a macromolecular complex composed of protein and RNA molecules. Just like their macroscopic counterparts, each of these nano-machines has an engine that "transduces" input energy into an output form which is then utilized by its coupling to a transmission system for appropriate operations. The theory of heat engines, pioneered by Carnot, rests on the second law of equilibrium thermodynamics. However, the engines of molecular machines, operate under isothermal conditions far from thermodynamic equilibrium. Moreover, one of the possible mechanisms of energy transduction, popularized by Feynman and called Brownian ratchet, does not even have any macroscopic counterpart. But, {\\it molecular machine is not synonymous with Brownian ratchet}; a large number of molecular machines actually execute a noisy power stroke, rather than operating as Brownian ratchet. The man-machine analogy, a topic of intense philosophical debate in which many leading philosophers like Aristotle and Descartes participated, was extended to similar analogies at the cellular and subcellular levels after the invention of optical microscope. The idea of molecular machine, pioneered by Marcelo Malpighi, has been pursued vigorously in the last fifty years. It has become a well established topic of current interdisciplinary research as evident from the publication of a very influential paper by Alberts towards the end of the twentieth century. Here we give a non-technical overview of the strategies for (a) stochastic modeling of mechano-chemical kinetic processes, and (b) model selection based on statistical inference drawn from analysis of experimental data. It is written for non-experts and from a broad perspective, showing overlapping concepts from several different branches of physics and from other areas of science and technology.
BoseEinstein condensation of quasi-equilibrium magnons at room temperature under pumping
Demokritov, S.O.
BoseEinstein condensation of quasi-equilibrium magnons at room temperature under pumping S. O BoseEinstein condensation1,2 is one of the most fascinating phenomena predicted by quantum mechanics momentum (bosons), if the particle density exceeds a critical value. To achieve BoseEinstein conden
Physica B 293 (2001) 283}288 Bose}Einstein condensation of noninteracting charged Bose gas
Bayindir, Mehmet
2001-01-01
Physica B 293 (2001) 283}288 Bose}Einstein condensation of noninteracting charged Bose gas of charged Bose particles. We conclude that Bose}Einstein condensation of the charged Bose gas occurs.75.Fi; 05.30.Jp; 67.40.Kh; 64.60.!i Keywords: Bose}Einstein condensation; External potentials; Density
A perturbative analysis of modulated amplitude waves in BoseEinstein condensates
Porter, Mason A.
A perturbative analysis of modulated amplitude waves in BoseEinstein condensates Mason A. Portera-temporal structures in nonlinear Schro¨dinger equations and thereby study the dynamics of quasi-one-dimensional BoseEinstein waves on their wave number. We also explore the band structure of BoseEinstein condensates in detail
Oscillations and interactions of dark and darkbright solitons in BoseEinstein
Loss, Daniel
ARTICLES Oscillations and interactions of dark and darkbright solitons in BoseEinstein in highly stable optically trapped 87 Rb BoseEinstein condensates. In particular, our detailed studies excitation in BoseEinstein condensates. Nowadays, solitons are a very active field of research in many areas
BoseEinstein condensation of atomic gases Frederic Chevy and Jean Dalibard
Dalibard, Jean
BoseEinstein condensation of atomic gases Fr´ed´eric Chevy and Jean Dalibard Laboratoire Kastler The discovery of the superfluid transition of liquid helium [1, 2] marked the first achievement of BoseEinstein, gaseous BoseEinstein condensates (BECs) discovered in 1995 after the development of laser cooling
Numerical analysis of BoseEinstein condensation in a three-dimensional harmonic oscillator potential
Ligare, Martin
Numerical analysis of BoseEinstein condensation in a three-dimensional harmonic oscillator 24 March 1997; accepted 12 May 1997 BoseEinstein condensation is the anomalous accumulation the conditions of the recent experiments achieving BoseEinstein condensation in laser-cooled alkali vapors
Toward a tomographic picture of a BoseEinstein Stefano Mancini
D'Ariano, Giacomo Mauro
Toward a tomographic picture of a BoseEinstein condensate Stefano Mancini Istituto Nazionale per 12, 2000 The possibilities of applying tomographic techniques to a BoseEinstein condensate have break- throughs in the evaporative cooling of dilute alkali gases allowed the generation of BoseEinstein
THREEPARTICLE BOSE--EINSTEIN CORRELATIONS a sensitive probe for Lund string fragmentation
Ringnér, Markus
THREEPARTICLE BOSE--EINSTEIN CORRELATIONS a sensitive probe for Lund string fragmentation M with respect to the jet axis in e + e \\Gamma annihilation, arises naturally in a model for BoseEinstein , and is a description of some features of the model for Bose--Einstein (BE) correlations developed in 2 (an extension
Residual BoseEinstein Correlations in Inclusive + \\Gamma Systems and the ae(770) 0 Line
Residual BoseEinstein Correlations in Inclusive ß + ß \\Gamma Systems and the ae(770) 0 Line Shape of multihadronic Z 0 decay, BoseEinstein correlations acting between identical pions may have significant indirect on experimental studies of BoseEinstein correlations, particularly with regard to the use of ß + ß \\Gamma
Bosonic Stimulation in the Formation of a Bose-Einstein Condensate
Bosonic Stimulation in the Formation of a Bose-Einstein Condensate H.-J. Miesner, D. M. Stamper-Kurn, M. R. Andrews, D. S. Durfee, S. Inouye, W. Ketterle The formation of a Bose-Einstein condensate atoms were evaporatively cooled close to the onset of Bose-Einstein condensation and then sud- denly
-Einstein condensate Collective excitations are the fingerprints of a system and reveal many of its dynamic properties. We extended earlier work on collective excitations of a Bose-Einstein condensate by studying them-Einstein condensation temperature. The temperature dependencies of the frequency and damping rates of condensate
Bose-Einstein Condensate: A New state of matter KISHORE T. KAPALE
Allen, Roland E.
Bose-Einstein Condensate: A New state of matter KISHORE T. KAPALE June 24, 2003 #12;BOSE-EINSTEIN CONDENSATE: A NEW STATE OF MATTER 1 Outline · Introductory Concepts Bosons and Fermions Classical and Quantum Statistics Intuitive picture of Bose-Einstein Condensation (BEC) Statistical mechanics of BECs Experimental
Derivation of the GrossPitaevskii Equation for the Dynamics of BoseEinstein Condensate
Derivation of the GrossPitaevskii Equation for the Dynamics of BoseEinstein Condensate LEinstein condensation states that at a very low temperature Bose systems with a pair interaction exhibit a collective mode, the BoseEinstein condensate. If one neglects the interaction and treats all bosons
July 12, 2007 Einstein's Miraculous Argument of 1905
signature of a microscopic energy distribution of independent, spatially localized components. The content century physics, the wave theory of light and its accommodation in electrodynamics. However the methods. In his statistical work of 1905, Einstein dealt with several thermal systems consisting of many
On the Einstein-Cartan cosmology vs. Planck data
Davor Palle
2014-05-14
The first comprehensive analyses of Planck data reveal that the cosmological model with dark energy and cold dark matter can satisfactorily explain the essential physical features of the expanding Universe. However, the inability to simultaneously fit large and small scale TT power spectrum, scalar power index smaller than one and the observations of the violation of the isotropy found by few statistical indicators of the CMB, urge theorists to search for explanations. We show that the model of the Einstein-Cartan cosmology with clustered dark matter halos and their corresponding clustered angular momenta coupled to torsion, can account for small scale - large scale discrepancy and larger peculiar velocities (bulk flows) for galaxy clusters. The nonvanishing total angular momentum (torsion) of the Universe enters as a negative effective density term in the Einstein-Cartan equations causing partial cancellation of the mass density. The integrated Sachs-Wolfe contribution of the Einstein-Cartan model is negative, thus it can provide partial cancellation of the large scale power of the TT CMB spectrum. The observed violation of the isotropy appears as a natural ingredient of the Einstein-Cartan model caused by the spin densities of light Majorana neutrinos in the early stage of the evolution of the Universe and bound to the lepton CP violation and matter-antimatter asymmetry.
Historical Approach to Physics according to Kant, Einstein, and Hegel
Kim, Y S
2013-01-01
It is known that Einstein's conceptual base for his theory of relativity was the philosophy formulated by Immanuel Kant. Things appear differently to observers in different frames. However, Kant's Ding-an-Sich leads to the existence of the absolute reference frame which is not acceptable in Einstein's theory. It is possible to avoid this conflict using the ancient Chinese philosophy of Taoism where two different views can co-exist in harmony. This is not enough to explain Einstein's discovery of the mass-energy relation. The energy-momentum relations for slow and ultra-fast particles take different forms. Einstein was able to synthesize these two formulas to create his energy-mass relation. Indeed, this is what Hegelianism is about in physics. Isaac Newton synthesized open orbits for comets and closed orbits for planets to create his second law of motion. Maxwell combined electricity and magnetism to create his four equations to the present-day wireless world. In order to synthesize wave and particle views of...
Radial motion into an Einstein-Rosen bridge
Nikodem J. Poplawski
2010-04-13
We consider the radial geodesic motion of a massive particle into a black hole in isotropic coordinates, which represents the exterior region of an Einstein-Rosen bridge (wormhole). The particle enters the interior region, which is regular and physically equivalent to the asymptotically flat exterior of a white hole, and the particle's proper time extends to infinity. Since the radial motion into a wormhole after passing the event horizon is physically different from the motion into a Schwarzschild black hole, Einstein-Rosen and Schwarzschild black holes are different, physical realizations of general relativity. Yet for distant observers, both solutions are indistinguishable. We show that timelike geodesics in the field of a wormhole are complete because the expansion scalar in the Raychaudhuri equation has a discontinuity at the horizon, and because the Einstein-Rosen bridge is represented by the Kruskal diagram with Rindler's elliptic identification of the two antipodal future event horizons. These results suggest that observed astrophysical black holes may be Einstein-Rosen bridges, each with a new universe inside that formed simultaneously with the black hole. Accordingly, our own Universe may be the interior of a black hole existing inside another universe.
Universality of the de Broglie-Einstein velocity equation
Yusuf Z. Umul
2007-12-06
The de Broglie-Einstein velocity equation is derived for a relativistic particle by using the energy and momentum relations in terms of wave and matter properties. It is shown that the velocity equation is independent from the relativistic effects and is valid also for the non-relativistic case. The results of this property is discussed.
Hamilton-Jacobi Counterterms for Einstein-Gauss-Bonnet Gravity
James T. Liu; Wafic A. Sabra
2008-07-08
The on-shell gravitational action and the boundary stress tensor are essential ingredients in the study of black hole thermodynamics. We employ the Hamilton-Jacobi method to calculate the boundary counterterms necessary to remove the divergences and allow the study of the thermodynamics of Einstein-Gauss-Bonnet black holes.
Emergent gravitational dynamics in Bose-Einstein condensates
Lorenzo Sindoni; Florian Girelli; Stefano Liberati
2009-09-29
We discuss a toy model for an emergent non-relativistic gravitational theory. Within a certain class of Bose-Einstein condensates, it is possible to show that, in a suitable regime, a modified version of non-relativistic Newtonian gravity does effectively describes the low energy dynamics of the coupled system condensate/quasi-particles.
Einstein-Yang-Mills theory : I. Asymptotic symmetries
Glenn Barnich; Pierre-Henry Lambert
2013-10-10
Asymptotic symmetries of the Einstein-Yang-Mills system with or without cosmological constant are explicitly worked out in a unified manner. In agreement with a recent conjecture, one finds a Virasoro-Kac-Moody type algebra not only in three dimensions but also in the four dimensional asymptotically flat case.
Einstein static Universe in hybrid metric-Palatini gravity
Christian G. Boehmer; Francisco S. N. Lobo; Nicola Tamanini
2015-02-18
Hybrid metric-Palatini gravity is a recent and novel approach to modified theories of gravity, which consists of adding to the metric Einstein-Hilbert Lagrangian an f(R) term constructed a la Palatini. It was shown that the theory passes local tests even if the scalar field is very light, and thus implies the existence of a long-range scalar field, which is able to modify the dynamics in galactic and cosmological scales, but leaves the Solar System unaffected. In this work, motivated by the possibility that the Universe may have started out in an asymptotically Einstein static state in the inflationary universe context, we analyse the stability of the Einstein static Universe by considering linear homogeneous perturbations in the respective dynamically equivalent scalar-tensor representation of hybrid metric-Palatini gravity. Considering linear homogeneous perturbations, the stability regions of the Einstein static universe are parametrized by the first and second derivatives of the scalar potential, and it is explicitly shown that a large class of stable solutions exists in the respective parameter space, in the context of hybrid metric-Palatini gravity.
What Is the Largest Einstein Radius in the Universe?
Oguri, Masamune; Blandford, Roger D.
2008-08-05
The Einstein radius plays a central role in lens studies as it characterizes the strength of gravitational lensing. In particular, the distribution of Einstein radii near the upper cutoff should probe the probability distribution of the largest mass concentrations in the universe. Adopting a triaxial halo model, we compute expected distributions of large Einstein radii. To assess the cosmic variance, we generate a number of Monte-Carlo realizations of all-sky catalogues of massive clusters. We find that the expected largest Einstein radius in the universe is sensitive to parameters characterizing the cosmological model, especially {sigma}{sub s}: for a source redshift of unity, they are 42{sub -7}{sup +9}, 35{sub -6}{sup +8}, and 54{sub -7}{sup +12} arcseconds (errors denote 1{sigma} cosmic variance), assuming best-fit cosmological parameters of the Wilkinson Microwave Anisotropy Probe five-year (WMAP5), three-year (WMAP3) and one-year (WMAP1) data, respectively. These values are broadly consistent with current observations given their incompleteness. The mass of the largest lens cluster can be as small as {approx} 10{sup 15} M{sub {circle_dot}}. For the same source redshift, we expect in all-sky {approx} 35 (WMAP5), {approx} 15 (WMAP3), and {approx} 150 (WMAP1) clusters that have Einstein radii larger than 2000. For a larger source redshift of 7, the largest Einstein radii grow approximately twice as large. While the values of the largest Einstein radii are almost unaffected by the level of the primordial non-Gaussianity currently of interest, the measurement of the abundance of moderately large lens clusters should probe non-Gaussianity competitively with cosmic microwave background experiments, but only if other cosmological parameters are well-measured. These semi-analytic predictions are based on a rather simple representation of clusters, and hence calibrating them with N-body simulations will help to improve the accuracy. We also find that these 'superlens' clusters constitute a highly biased population. For instance, a substantial fraction of these superlens clusters have major axes preferentially aligned with the line-of-sight. As a consequence, the projected mass distributions of the clusters are rounder by an ellipticity of {approx} 0.2 and have {approx} 40%-60% larger concentrations compared with typical clusters with similar redshifts and masses. We argue that the large concentration measured in A1689 is consistent with our model prediction at the 1.2{sigma} level. A combined analysis of several clusters will be needed to see whether or not the observed concentrations conflict with predictions of the at {Lambda}-dominated cold dark matter model.
Method and apparatus for distinguishing actual sparse events from sparse event false alarms
Spalding, Richard E. (Albuquerque, NM); Grotbeck, Carter L. (Albuquerque, NM)
2000-01-01
Remote sensing method and apparatus wherein sparse optical events are distinguished from false events. "Ghost" images of actual optical phenomena are generated using an optical beam splitter and optics configured to direct split beams to a single sensor or segmented sensor. True optical signals are distinguished from false signals or noise based on whether the ghost image is presence or absent. The invention obviates the need for dual sensor systems to effect a false target detection capability, thus significantly reducing system complexity and cost.
Distinguishing Neutrino Mass Hierarchies using Dark Matter Annihilation Signals at IceCube
Rouzbeh Allahverdi; Bhaskar Dutta; Dilip Kumar Ghosh; Bradley Knockel; Ipsita Saha
2015-06-27
We explore the possibility of distinguishing neutrino mass hierarchies through the neutrino signal from dark matter annihilation at neutrino telescopes. We consider a simple extension of the standard model where the neutrino masses and mixing angles are obtained via the type-II seesaw mechanism. We show that for a detector with the same capability as the IceCube DeepCore array, multiyear data from DM annihilation at the Galactic Center and inside the Sun can be used to distinguish the normal and inverted neutrino mass hierarchies.
An Electrical Spinning Particle In Einstein's Unified Field Theory
S. N. Pandey; B. K. Sinha; Raj Kumar
2006-10-01
Previous work on exact solutions has been shown that sources need to be appended to the field equation of Einstein's unified field theory in order to achieve physically meaningful results,such sources can be included in a variational formulation by Borchsenius and moffat.The resulting field equations and conservation identities related to the theory that can be used to derive the equations of structure and motion of a pole-dipole particle according to an explicitly covariant approach by Dixon6.In this present paper it is shown that,under certain conditions for the energy tensor of the spinning particle,the equations of structure and motion in an electromagnetic field turn out to be formly identical to those occurring in Einstein-Maxwell theory.
Back reaction of the neutrino field in an Einstein universe
M. B. Altaie
2002-12-31
The back reaction effect of the neutrino field at finite temperature in the background of the static Einstein universe is investigated. A relationship between the temperature of the universe and its radius is found. As in the previously studied cases of the massless scalar field and the photon field, this relation exhibit a minimum radius below which no self-consistent solution for the Einstein field equation can be found. A maximum temperature marks the transition from a vacuum dominated state to the radiation dominated state universe. In the light of the results obtained for the scalar, neutrino and photon fields the role of the back reaction of quantum fields in controling the value of the cosmological constant is briefly discussed.
Scalar field as a Bose-Einstein condensate?
Castellanos, Elías; Escamilla-Rivera, Celia; Macías, Alfredo; Núñez, Darío E-mail: cescamilla@mctp.mx E-mail: nunez@nucleares.unam.mx
2014-11-01
We discuss the analogy between a classical scalar field with a self-interacting potential, in a curved spacetime described by a quasi-bounded state, and a trapped Bose-Einstein condensate. In this context, we compare the Klein-Gordon equation with the Gross-Pitaevskii equation. Moreover, the introduction of a curved background spacetime endows, in a natural way, an equivalence to the Gross-Pitaevskii equation with an explicit confinement potential. The curvature also induces a position dependent self-interaction parameter. We exploit this analogy by means of the Thomas-Fermi approximation, commonly used to describe the Bose-Einstein condensate, in order to analyze the quasi bound scalar field distribution surrounding a black hole.
Generalized Einstein Relation in an aging colloidal glass
Bérengère Abou; François Gallet; Pascal Monceau; Noëlle Pottier
2007-05-29
We present an experimental and theoretical investigation of the Generalized Einstein Relation (GER), a particular form of a fluctuation-dissipation relation, in an out-of-equilibrium visco-elastic fluid. Micrometer beads, used as thermometers, are immersed in an aging colloidal glass to provide both fluctuation and dissipation measurements. The deviations from the Generalized Einstein Relation are derived as a function of frequency and aging time. The observed deviations from GER are interpreted as directly related to the change in the glass relaxation times with aging time. In our scenario, deviations are observed in the regime where the observation time scale is of the order of a characteristic relaxation time of the glass.
The Dilute Bose-Einstein Condensate with Large Scattering Length
Eric Braaten; H. -W. Hammer; Thomas Mehen
2002-02-01
We study a dilute Bose gas of atoms whose scattering length a is large compared to the range of their interaction. We calculate the energy density of the homogeneous Bose-Einstein condensate to second order in the low-density expansion, expressing it in terms of a and a second parameter Lambda_* that determines the low-energy observables in the 3-body sector. The second-order correction to the energy density has a small imaginary part that reflects the instability due to 3-body recombination. In the case of a trapped Bose-Einstein condensate with large negative scattering length, we calculate the coefficient of the 3-body mean-field term in the energy density in terms of a and Lambda_*. It can be very large if there is an Efimov state near threshold.
Interferometry with Bose-Einstein Condensates in Microgravity
H. Müntinga; H. Ahlers; M. Krutzik; A. Wenzlawski; S. Arnold; D. Becker; K. Bongs; H. Dittus; H. Duncker; N. Gaaloul; C. Gherasim; E. Giese; C. Grzeschik; T. W. Hänsch; O. Hellmig; W. Herr; S. Herrmann; E. Kajari; S. Kleinert; C. Lämmerzahl; W. Lewoczko-Adamczyk; J. Malcolm; N. Meyer; R. Nolte; A. Peters; M. Popp; J. Reichel; A. Roura; J. Rudolph; M. Schiemangk; M. Schneider; S. T. Seidel; K. Sengstock; V. Tamma; T. Valenzuela; A. Vogel; R. Walser; T. Wendrich; P. Windpassinger; W. Zeller; T. van Zoest; W. Ertmer; W. P. Schleich; E. M. Rasel
2013-01-24
Atom interferometers covering macroscopic domains of space-time are a spectacular manifestation of the wave nature of matter. Due to their unique coherence properties, Bose-Einstein condensates are ideal sources for an atom interferometer in extended free fall. In this paper we report on the realization of an asymmetric Mach-Zehnder interferometer operated with a Bose-Einstein condensate in microgravity. The resulting interference pattern is similar to the one in the far-field of a double-slit and shows a linear scaling with the time the wave packets expand. We employ delta-kick cooling in order to enhance the signal and extend our atom interferometer. Our experiments demonstrate the high potential of interferometers operated with quantum gases for probing the fundamental concepts of quantum mechanics and general relativity.
Polymer quantization of the Einstein-Rosen wormhole throat
G. Kunstatter; J. Louko; A. Peltola
2010-01-23
We present a polymer quantization of spherically symmetric Einstein gravity in which the polymerized variable is the area of the Einstein-Rosen wormhole throat. In the classical polymer theory, the singularity is replaced by a bounce at a radius that depends on the polymerization scale. In the polymer quantum theory, we show numerically that the area spectrum is evenly-spaced and in agreement with a Bohr-Sommerfeld semiclassical estimate, and this spectrum is not qualitatively sensitive to issues of factor ordering or boundary conditions except in the lowest few eigenvalues. In the limit of small polymerization scale we recover, within the numerical accuracy, the area spectrum obtained from a Schrodinger quantization of the wormhole throat dynamics. The prospects of recovering from the polymer throat theory a full quantum-corrected spacetime are discussed.
Piepke, Andreas G.
. Kravitz, M. Montero Díez, G. Gratta, W. Fairbank Jr., J. B. Albert, D. J. Auty, P. S. Barbeau, D. Beck, C to manipulate and identify individual Ba ions from bulk liquid Xe K. Twelker,1 S. Kravitz,1 M. Montero Díez,1,a
Foreword The field of BoseEinstein condensation in atomic gases has been full of sur- prises. What happened after the first realization of BoseEinstein condensates in 1995 has far exceeded the vision of their creators. Originally, I expected interesting studies of equilibrium properties and dynamics, but the Bose
Bragg spectroscopy of a Bose-Einstein condensate The first evidence for Bose-Einstein condensation distribution of the expanding condensate was the released interaction energy (mean-field energy) resulting potential. Since the size of a trapped condensate with repulsive interactions is larger than the trap ground
Geometry and experience: Einstein's 1921 paper and Hilbert's axiomatic system
De Gandt, Francois [Universite Lille III, UMR 8163 'Savoirs et Textes', BP 60149, 59653 Villeneuve d'Ascq (France)
2006-06-19
In his 1921 paper Geometrie und Erfahrung, Einstein decribes the new epistemological status of geometry, divorced from any intuitive or a priori content. He calls that 'axiomatics', following Hilbert's theoretical developments on axiomatic systems, which started with the stimulus given by a talk by Hermann Wiener in 1891 and progressed until the Foundations of geometry in 1899. Difficult questions arise: how is a theoretical system related to an intuitive empirical content?.
On the Bartnik conjecture for the static vacuum Einstein equations
Anderson, Michael T
2015-01-01
We prove that given any smooth metric $\\gamma$ and smooth positive function $H$ on $S^{2}$, there is a constant $\\lambda > 0$, depending on $(\\gamma, H)$, and an asymptotically flat solution $(M, g, u)$ of the static vacuum Einstein equations on $M = {\\mathbb R}^{3} \\setminus B^{3}$, such that the induced metric and mean curvature of $(M, g, u)$ at $\\partial M$ are given by $(\\gamma, \\lambda H)$. This gives a partial resolution of a conjecture of Bartnik.
A Hamiltonian functional for the linearized Einstein vacuum field equations
R. Rosas-Rodriguez
2005-07-26
By considering the Einstein vacuum field equations linearized about the Minkowski metric, the evolution equations for the gauge-invariant quantities characterizing the gravitational field are written in a Hamiltonian form by using a conserved functional as Hamiltonian; this Hamiltonian is not the analog of the energy of the field. A Poisson bracket between functionals of the field, compatible with the constraints satisfied by the field variables, is obtained. The generator of spatial translations associated with such bracket is also obtained.
Black holes vs. naked singularities formation in collapsing Einstein's clusters
S. Jhingan; G. Magli
2000-01-10
Non-static, spherically symmetric clusters of counter-rotating particles, of the type first introduced by Einstein, are analysed here. The initial data space can be parameterized in terms of three arbitrary functions, namely; initial density, velocity and angular momentum profiles. The final state of collapse, black hole or naked singularity, turns out to depend on the order of the first non-vanishing derivatives of such functions at the centre. The work extends recent results by Harada, Iguchi and Nakao.
Controllable scattering of vector Bose-Einstein solitons
Babarro, Judit; Paz-Alonso, Maria J.; Michinel, Humberto; Salgueiro, Jose R.; Olivieri, David N.
2005-04-01
We show the possibility of producing matter-wave switching devices by using Manakov interactions between vector matter-wave solitons using two-species Bose-Einstein condensates (BECs). Our results establish the experimental parameters for three interaction regimes in two-species BECs: symmetric and asymmetric splitting, down-switching, and up-switching. We have studied the dependence upon the initial conditions and the kind of interaction between the two matter-wave solitons.
Time-Periodic Solutions of the Einstein's Field Equations II
De-Xing Kong; Kefeng Liu; Ming Shen
2008-07-31
In this paper, we construct several kinds of new time-periodic solutions of the vacuum Einstein's field equations whose Riemann curvature tensors vanish, keep finite or take the infinity at some points in these space-times, respectively. The singularities of these new time-periodic solutions are investigated and some new physical phenomena are found. The applications of these solutions in modern cosmology and general relativity can be expected.
Formation of molecules in an expanding Bose-Einstein condensate
V. A. Yurovsky; A. Ben-Reuven
2004-02-12
A mean field theory of expanding hybrid atom-molecule Bose-Einstein condensates is applied to the recent MPI experiments on ${}^{87}$Rb that demonstrated the formation of ultracold molecules due to Feshbach resonance. The subsequent dissociation of the molecules is treated using a non-mean-field parametric approximation. The latter method is also used in determining optimal conditions for the formation of molecular BEC
Qubit residence time measurements with a Bose-Einstein condensate
D. Sokolovski
2009-02-23
We show that an electrostatic qubit located near a Bose-Einstein condensate trapped in a symmetric double-well potential can be used to measure the duration the qubit has spent in one of its quantum states. The stronq, medium and weak measurement regimes are analysed and a new type of Zeno effect is discussed. The analogy between the residence and the traversal (tunnelling) times is highlighted.
Controlling chaos in the Bose-Einstein condensate
Cong Fuzhong, E-mail: wzx2007111@126.com; Wang Zhixia; Hua Hongtu; Pang Shichun; Tong Shouyu [Aviation University of Air Force (China)
2012-03-15
The spatial structure of the Bose-Einstein condensate (BEC) is investigated and spatially chaotic distributions of the condensates are revealed. By means of changing the s-wave scattering length with a Feshbach resonance, the chaotic behavior can be well controlled to enter into periodicity. Numerical simulation shows that there are different periodic orbits according to different s-wave scattering lengths only if the Lyapunov exponent of the system is negative.
A Machian Version of Einstein's Variable Speed of Light Theory
Alexander Unzicker; Jan Preuss
2015-03-28
It is a little known fact that while he was developing his theory of general relativity, Einstein's initial idea was a variable speed of light theory. Indeed space-time curvature can be mimicked by a speed of light $c(r)$ that depends on the distribution of masses. Einstein's 1911 theory was considerably improved by Robert Dicke in 1957, but only recently has the equivalence of the variable speed of light approach to the conventional formalism been demonstrated (Broekaert, 2008). Using Green's functions, we show that Einstein's 1911 idea can be expressed in an analytic form, similar to the Poisson equation. Using heuristic arguments, we derive a simple formula that directly relates curvature $w$ to the local speed of light, $w= -c^2 \\Delta \\frac{1}{c^2}$. In contrast to the conventional formulation, this allows for a Machian interpretation of general relativity and the gravitational constant $G$. Gravity, though described by local equations, has its origin in all other masses in the universe.
Distinguishers for the Compression Function and Output Transformation of Hamsi-256
International Association for Cryptologic Research (IACR)
Distinguishers for the Compression Function and Output Transformation of Hamsi-256 Jean, with digital signatures and integrity checks as their main applications. Collision attacks on the deployed as the full 6-round output transformation. The former gives near-collisions on (256 - 25) bits
Distinguishing protein-coding and noncoding genes in the human genome
Kellis, Manolis
) Although the Human Genome Project was completed 4 years ago, the catalog of human protein-coding genesDistinguishing protein-coding and noncoding genes in the human genome Michele Clamp* , Ben Fry An accurate catalog of the protein-coding genes encoded in the human genome is fundamental to the study
Danny D. Reible, PhD PE BCEE NAE Donovan Maddox Distinguished Engineering Chair
Chen, Xinzhong
Union, American Society for Engineering Education, Association of Environmental Engineering and ScienceDanny D. Reible, PhD PE BCEE NAE Donovan Maddox Distinguished Engineering Chair Environmental and Water Resources, Civil and Environmental Engineering, Texas Tech University Ph: 806-742-3523 Fax: 806
civil and environmental engineering department presents 2013 Kirlin Distinguished Speaker Series
Aydilek, Ahmet
civil and environmental engineering department presents 2013 Kirlin Distinguished Speaker Series Dr. Craig H. Benson Director of Sustainability Research & Education Co-Director of the Office of Sustainability University of Wisconsin- Madison Dr. Craig H. Benson is an international expert in environmental
Detailed balance in micro-and macrokinetics and micro-distinguishability of macro-processes
Detailed balance in micro- and macrokinetics and micro-distinguishability of macro-processes A. N a general framework for the discussion of detailed balance and analyse its microscopic background. We find of detailed balance. Keywords: kinetic equation, random process, microreversibility, detailed balance
Hammack, Richard
Policy on professorships and chairs 1 Current Revision: 01/2013 Policy on professorships, distinguished professorships, chairs and chair elevations Policy Type: Local Responsible Office: Office of Development and Alumni Relations Initial Policy Approved: 05/2009 Revised Policy Approved: 01/2013 Policy
Lee, H.C. Paul
fragility). A key research problem is distinguishing among laws, protocols, and historical frequency and voltag- es of delivered power, oil refineries have 10,000 such control loops, and Internet, terabytes of data, and a billion-dollar price tag. 55. Systems Biology Workbench (www.cds.caltech.edu/ sbw
Albert, Réka
;#12;#12;#12;Vertex Pre Post a 1 8 b 2 7 c 3 6 d 4 2 e 5 1 f 6 4 g 7 3 h 8 5 #12;Properties of DFS trees for a link Pre Post a 1 8 b 2 7 e 3 6 g 4 5 c 5 4 h 6 3 d 7 2 f 8 1 #12;Properties of BFS traversal Corresponds the depth first search on its reverse and compute the post-order numbering. Then run the search again
Einstein's Dream of Unified Forces - principles | U.S. DOE Office...
Office of Science (SC) Website
Einstein's Dream of Unified Forces High Energy Physics (HEP) HEP Home About Research Science Drivers of Particle Physics Energy Frontier Intensity Frontier Cosmic Frontier...
Instability of Schwarzschild-AdS black hole in Einstein-Weyl gravity
Yun Soo Myung
2013-12-09
We investigate the classical stability of Schwarzschild-AdS black hole in a massive theory of the Einstein-Weyl gravity. It turns out that the linearized Einstein tensor perturbations exhibit unstable modes featuring the Gregory-Laflamme instability of five-dimensional AdS black string, in contrast to the stable Schwarzschild-AdS black hole in the Einstein-Weyl gravity. We confirm that the instability of the black hole in the Einstein-Weyl gravity arises from the massiveness but not a feature of fourth-order derivative theory giving ghost states.
Chikkatur, Ananth P.
2006-02-22
In this thesis, two different sets of experiments are described. The first is an exploration of the microscopic superfluidity of dilute gaseous Bose- Einstein condensates. The second set
J. A. Shifflett
2008-02-08
We modify the Einstein-Schrodinger theory to include a cosmological constant $\\Lambda_z$ which multiplies the symmetric metric, and we show how the theory can be easily coupled to additional fields. The cosmological constant $\\Lambda_z$ is assumed to be nearly cancelled by Schrodinger's cosmological constant $\\Lambda_b$ which multiplies the nonsymmetric fundamental tensor, such that the total $\\Lambda=\\Lambda_z+\\Lambda_b$ matches measurement. The resulting theory becomes exactly Einstein-Maxwell theory in the limit as $|\\Lambda_z|\\to\\infty$. For $|\\Lambda_z|\\sim 1/(Planck length)^2$ the field equations match the ordinary Einstein and Maxwell equations except for extra terms which are $electromagnetic vector potential, just as in Einstein-Maxwell theory. The ordinary Lorentz force equation is obtained by taking the divergence of the Einstein equations when sources are included. The Einstein-Infeld-Hoffmann (EIH) equations of motion match the equations of motion for Einstein-Maxwell theory to Newtonian/Coulombian order, which proves the existence of a Lorentz force without requiring sources. This fixes a problem of the original Einstein-Schrodinger theory, which failed to predict a Lorentz force. An exact charged solution matches the Reissner-Nordstrom solution except for additional terms which are $\\sim 10^{-66}$ of the usual terms for worst-case radii accessible to measurement. An exact electromagnetic plane-wave solution is identical to its counterpart in Einstein-Maxwell theory.
G. A. Alekseev
2014-11-13
Applications of the monodromy transform approach to construction of exact solutions of electrovacuum Einstein - Maxwell field equations are considered. Examples of new solutions are given.
On the curvature of Einstein-Hermitian surfaces
Mustafa Kalafat; Caner Koca
2014-10-19
We give a mathematical exposition of the Page metric and introduce an efficient coordinate system for it. We carefully examine the submanifolds of the underlying smooth manifold and show that it does not have positive holomorphic bisectional curvature. We also reprove that a compact complex surface together with an Einstein-Hermitian metric of positive orthogonal bisectional curvature is biholomorphically isometric to the complex projective plane with its Fubini-Study metric up to rescaling. This result relaxes the K\\"ahler condition in Berger's theorem, and the positivity condition on sectional curvature in a theorem proved by Koca.
Anisotropic Einstein data with isotropic nonnegative scalar curvature
Bernold Fiedler; Juliette Hell; Brian Smith
2012-07-11
We construct a black hole initial data for the Einstein equations with prescribed scalar curvature, or more precisely a piece of initial data contained inside the black hole. The constraints translate into a parabolic equation, with radius as "time" variable, on a metric component u that undergoes blow up. The metric itself is regular up to and including the surface at blow up radius, which is a minimal surface. By applying equivariant bifurcation theory on a self similarly rescaled equation, we show the existence of blow up profiles that are not O(3) symmetric - or anisotropic - although the curvature was isotropically prescribed.
Black Hole Thermodynamic Products in Einstein Gauss Bonnet Gravity
Mandal, Abhijit
2015-01-01
We study the thermodynamic properties of black hole horizons in Einstein Gauss Bonnet gravity. We derive the thermodynamic products of characteristic parameters to mark which are global. We further interpret the stability of the black holes by computing the specific heat for both horizons. Stable and unstable phases of horizons are pointed out. The phase transitions with respect to the charge in nature of specific heat are also observed. All these calculation might be helpful to understand the microscopic nature of such black holes.
A New Solution of Einstein Vacuum Field Equations
Ram Gopal Vishwakarma
2014-09-11
A new solution of Einstein's vacuum field equations is discovered which appears as a generalization of the well-known Ozsvath-Schucking solution and explains its source of curvature which has otherwise remained hidden. Curiously, the new solution has a vanishing Kretschmann scalar and is singularity-free despite being curved. The discovery of the new solution is facilitated by a new insight which reveals that it is always possible to define the source of curvature in a vacuum solution in terms of some dimensional parameters. As the parameters vanish, so does the curvature. The new insight also helps to make the vacuum solutions Machian.
Einstein-Proca Model, Micro Black Holes, and Naked Singularities
Chris Vuille; James Ipser; Jeff Gallagher
2014-05-31
The Einstein-Proca equations, describing a spin-1 massive vector field in general relativity, are studied in the static, spherically-symmetric case. The Proca field equation is a highly nonlinear wave equation, but can be solved to good accuracy in perturbation theory, which should be very accurate for a wide range of mass scales. The resulting first order metric reduces to the Reissner-Nordstrom solution in the limit as the range parameter $\\mu$ goes to zero. The additional terms in the $g_{00}$ metric are positive, as in Reissner-Nordstrom, in agreement with previous numerical solutions, and hence involve naked singularities.
On isotropic metric of Schwarzschild solution of Einstein equation
T. Mei
2006-10-24
The known static isotropic metric of Schwarzschild solution of Einstein equation cannot cover with the range of r<2MG, a new isotropic metric of Schwarzschild solution is obtained. The new isotropic metric has the characters: (1) It is dynamic and periodic. (2) It has infinite singularities of the spacetime. (3) It cannot cover with the range of 0
How Einstein's quantum hypothesis requires a departure from classical mechanics
Gabriele Carcassi
2009-02-16
The aim of this work is to show how Einstein's quantum hypothesis leads immediately and necessarily to a departure from classical mechanics. First we note that the classical description and predictions are in terms of idealized measurements that are exact, instantaneous, non-perturbative, independent of each other and process agnostic. If we assume we cannot arbitrarily reduce the strength of a signal, measurements are ultimately perturbative to some degree. We show how a physical description in which the best measurement conceivable, i.e. the ideal measurement, perturbs the system leads to all the concepts present in quantum mechanics including conjugate variables, probabilistic predictions and measurements connected to symmetries.
Conformastationary disk-haloes in Einstein-Maxwell gravity
Antonio C. Gutiérrez-Piñeres
2015-04-14
An exact solution of the Einstein-Maxwell field equations for a conformastationary metric with magnetized disk-haloes sources is worked out in full. The characterization of the nature of the energy momentum tensor of the source is discussed. All the expressions are presented in terms of a solution of the Laplace's equation. A "generalization" of the Kuzmin solution of the Laplace's equations is used as a particular example. The solution obtained is asymptotically flat in general and turns out to be free of singularities. All the relevant quantities show a reasonable physical behaviour.
Study on Cooling of Positronium for Bose-Einstein Condensation
Kenji Shu; Xing Fan; Takayuki Yamazaki; Toshio Namba; Shoji Asai; Kosuke Yoshioka; Makoto Kuwata-Gonokami
2015-11-25
A new method of cooling positronium down is proposed to realize Bose-Einstein condensation of positronium. We perform detail studies about three processes (1) thermalization processes between positronium and silica walls of a cavity, (2) Ps-Ps scatterings and (3) Laser cooling. The thermalization process is shown to be not sufficient for BEC. Also Ps-Ps collision is shown to make a big effect on the cooling performance. We combine both methods and establish an efficient cooling for BEC. We also propose a new optical laser system for the cooling.
Static Einstein-Maxwell Solutions in 2+1 dimensions
Mauricio Cataldo; Patricio Salgado
1996-05-22
We obtain the Einstein-Maxwell equations for (2+1)-dimensional static space-time, which are invariant under the transformation $q_0=i\\,q_2,q_2=i\\,q_0,\\alpha \\rightleftharpoons \\gamma$. It is shown that the magnetic solution obtained with the help of the procedure used in Ref.~\\cite{Cataldo}, can be obtained from the static BTZ solution using an appropriate transformation. Superpositions of a perfect fluid and an electric or a magnetic field are separately studied and their corresponding solutions found.
Bose-Einstein Condensation of Dark Matter Axions
P. Sikivie; Q. Yang
2009-09-02
We show that cold dark matter axions thermalize and form a Bose-Einstein condensate. We obtain the axion state in a homogeneous and isotropic universe, and derive the equations governing small axion perturbations. Because they form a BEC, axions differ from ordinary cold dark matter in the non-linear regime of structure formation and upon entering the horizon. Axion BEC provides a mechanism for the production of net overall rotation in dark matter halos, and for the alignment of cosmic microwave anisotropy multipoles.
Electrical charges in gravitational fields, and Einstein's equivalence principle
Gerold Gründler
2015-10-12
According to Larmor's formula, accelerated electric charges radiate electromagnetic waves. Hence charges should radiate, if they are in free fall in gravitational fields, and they should not radiate if they are supported at rest in gravitational fields. But according to Einstein's equivalence principle, charges in free fall should not radiate, while charges supported at rest in gravitational fields should radiate. In this article we point out indirect experimental evidence, indicating that the equivalence principle is correct, while the traditional interpretation of Larmor's formula must be amended.
Causality Constraint on Noncritical Einstein-Weyl Gravity
Fu-Wen Shu; Yungui Gong
2014-10-31
We explore, in the context of AdS/CFT correspondence, the causality constraints on the Noncritical Einstein-Weyl (NEW) gravity model in five dimensions. The scalar and shear channels are considered as small metric perturbations around an AdS black brane background. Our results show that causality analysis on the propagation of these two channels imposes a new bound on the coupling of the Weyl-squared terms in the NEW gravity. This new bound imposes more stringent restrictions than those of the tachyon-free condition, improving predictive power of the theory.
Amplification of Fluctuations in a Spinor Bose Einstein Condensate
S. R. Leslie; J. Guzman; M. Vengalattore; J. D. Sau; M. L. Cohen; D. M. Stamper-Kurn
2008-06-10
Dynamical instabilities due to spin-mixing collisions in a $^{87}$Rb F=1 spinor Bose-Einstein condensate are used as an amplifier of quantum spin fluctuations. We demonstrate the spectrum of this amplifier to be tunable, in quantitative agreement with mean-field calculations. We quantify the microscopic spin fluctuations of the initially paramagnetic condensate by applying this amplifier and measuring the resulting macroscopic magnetization. The magnitude of these fluctuations is consistent with predictions of a beyond-mean-field theory. The spinor-condensate-based spin amplifier is thus shown to be nearly quantum-limited at a gain as high as 30 dB.
Electrical charges in gravitational fields, and Einstein's equivalence principle
Gerold Gründler
2015-10-06
According to Larmor's formula, accelerated electric charges radiate electromagnetic waves. Hence charges should radiate, if they are in free fall in gravitational fields, and they should not radiate if they are supported at rest in gravitational fields. But according to Einstein's equivalence principle, charges in free fall should not radiate, while charges supported at rest in gravitational fields should radiate. In this article we point out indirect experimental evidence, indicating that the equivalence principle is correct, while Larmor's formula must be interpreted different than commonly accepted.
Quasi-Nambu-Goldstone Modes in Bose-Einstein Condensates
Uchino, Shun [Department of Physics, University of Tokyo, 7-3-1 Hongo, Tokyo 113-0033 (Japan); Kobayashi, Michikazu [Department of Basic Science, University of Tokyo, 3-8-1 Komaba, Tokyo 153-8902 (Japan); Nitta, Muneto [Department of Physics, and Research and Education Center for Natural Sciences, Keio University, 4-1-1 Hiyoshi, Kanagawa 223-8521 (Japan); Ueda, Masahito [Department of Physics, University of Tokyo, 7-3-1 Hongo, Tokyo 113-0033 (Japan); ERATO Macroscopic Quantum Project, JST, Tokyo 113-8656 (Japan)
2010-12-03
We show that quasi-Nambu-Goldstone (NG) modes, which play prominent roles in high energy physics but have been elusive experimentally, can be realized with atomic Bose-Einstein condensates. The quasi-NG modes emerge when the symmetry of a ground state is larger than that of the Hamiltonian. When they appear, the conventional vacuum manifold should be enlarged. Consequently, topological defects that are stable within the conventional vacuum manifold become unstable and decay by emitting the quasi-NG modes. Contrary to conventional wisdom, however, we show that the topological defects are stabilized by quantum fluctuations that make the quasi-NG modes massive, thereby suppressing their emission.
Three-dimensional asymptotically flat Einstein-Maxwell theory
Glenn Barnich; Pierre-Henry Lambert; Pujian Mao
2015-03-03
Three-dimensional Einstein-Maxwell theory with non trivial asymptotics at null infinity is solved. The symmetry algebra is a Virasoro-Kac-Moody type algebra that extends the bms3 algebra of the purely gravitational case. Solution space involves logarithms and provides a tractable example of a polyhomogeneous solution space. The associated surface charges are non-integrable and non-conserved due to the presence of electromagnetic news. As in the four dimensional purely gravitational case, their algebra involves a field-dependent central charge.
New first-order formulation for the Einstein equations
A. M. Alekseenko; D. N. Arnold
2004-05-16
We derive a new first-order formulation for Einstein's equations which involves fewer unknowns than other first-order formulations that have been proposed. The new formulation is based on the 3+1 decomposition with arbitrary lapse and shift. In the reduction to first order form only 8 particular combinations of the 18 first derivatives of the spatial metric are introduced. In the case of linearization about Minkowski space, the new formulation consists of symmetric hyperbolic system in 14 unknowns, namely the components of the extrinsic curvature perturbation and the 8 new variables, from whose solution the metric perturbation can be computed by integration.
Jennifer M. Smillie; Bryan R. Webber
2007-02-21
An interesting alternative to supersymmetry (SUSY) for extending physics beyond the Standard Model is a model with universal extra dimensions (UED), in which the SUSY superpartners are replaced by Kaluza-Klein excitations of the Standard Model particles. If new particles are discovered at the LHC, even if their mass spectrum favours SUSY or UED, it will be vital to distinguish between their spin assignments in the two models as far as possible. We extend the method proposed by Barr [hep-ph/0405052] to the UED case and investigate the angular and charge asymmetries of decay distributions for sample mass spectra of both SUSY and UED types. For hierarchical (`SUSY-type') mass spectra there is a good chance of distinguishing the spin structures of the two models. However, a mass spectrum of the quasi-degenerate type expected in UED would make it difficult to observe spin correlations.
Han, Heekyung; Wardlaw, David M.; Frolov, Alexei M.
2014-05-28
We examine the effect of decoherence and intermolecular interactions (chiral discrimination energies) on the chiral stability and the distinguishability of initially pure versus mixed states in an open chiral system. Under a two-level approximation for a system, intermolecular interactions are introduced by a mean-field theory, and interaction between a system and an environment is modeled by a continuous measurement of a population difference between the two chiral states. The resultant equations are explored for various parameters, with emphasis on the combined effects of the initial condition of the system, the chiral discrimination energies, and the decoherence in determining: the distinguishability as measured by a population difference between the initially pure and mixed states, and the decoherence process; the chiral stability as measured by the purity decay; and the stationary state of the system at times long relative to the time scales of the system dynamics and of the environmental effects.
Distinguishing a SM-like MSSM Higgs boson from SM Higgs boson at muon collider
Jai Kumar Singhal; Sardar Singh; Ashok K Nagawat
2005-07-26
We explore the possibility of distinguishing the SM-like MSSM Higgs boson from the SM Higgs boson via Higgs boson pair production at future muon collider. We study the behavior of the production cross section in SM and MSSM with Higgs boson mass for various choices of MSSM parameters tan \\beta and m\\sub A. We observe that at fixed CM energy, in the SM, the total cross section increases with the increase in Higgs boson mass whereas this trend is reversed for the MSSM case. The changes that occur for the MSSM case in comparison to the SM predictions are quantified in terms of the relative percentage deviation in cross section. The observed large deviations in cross section for different choices of Higgs mass suggest that the measurements of the cross section could possibly distinguish the SM-like MSSM Higgs boson from the SM Higgs boson.
Breakdown of the Stokes-Einstein Relation in Supercooled Water
Pradeep Kumar; S. V. Buldyrev; S. R. Becker; P. H. Poole; F. W. Starr; H. E. Stanley
2007-02-06
Supercooled water exhibits a breakdown of the Stokes-Einstein relation between the diffusion constant $D$ and the alpha relaxation time $\\tau_{\\alpha}$. For water simulated with the TIP5P and ST2 potentials, we find that the temperature of the decoupling of diffusion and alpha relaxation correlates with the temperature of the maximum in specific heat that corresponds to crossing the Widom line $T_W(P)$. Specifically, we find that our results for $D\\tau_{\\alpha}/T$ collapse onto a single master curve if temperature is replaced by $T-T_W(P)$, where $T_W(P)$ is the temperature where the constant-pressure specific heat achieves a maximum. Also, we find agreement between our ST2 simulations and experimental values of $D\\tau_{\\alpha}/T$. We further find that the size of the mobile molecule clusters (dynamical heterogeneities) increases sharply near $T_W(P)$. Moreover, our calculations of mobile particle cluster size $_w$ for different pressures, where $t^*$ is the time for which the mobile particle cluster size is largest, also collapse onto a single master curve if $T$ is replaced by $T-T_W(P)$. The crossover to a more locally structured low density liquid (LDL) environment as $T\\to T_W(P)$ appears to be well correlated with both the breakdown of the Stokes-Einstein relation and the growth of dynamic heterogeneities.
Einstein's first gravitational field equation 101 years latter
Juan Betancort-Rijo; Felipe Jimenez Ibarra
2014-01-10
We review and strengthen the arguments given by Einstein to derive his first gravitational field equation for static fields and show that, although it was ultimately rejected, it follows from General Relativity (GR) for negligible pressure. Using this equation and considerations folowing directly from the equivalence principle (EP), we show how Schwarzschild metric and other vacum metrics can be obtained immediately. With this results and some basic principles, we obtain the metric in the general spherically symmetric case and the corresponding hydrostatic equilibrium equation. For this metrics we obtain the motion equations in a simple and exact manner that clearly shows the three sources of difference (implied by various aspects of the EP) with respect to the Newtonian case and use them to study the classical tests of GR. We comment on the origin of the problems of Einstein first theory of gravity and discuss how, by removing it the theory could be made consistent and extended to include rotations, we also comments on various conceptual issues of GR as the origin of the gravitational effect of pressure.
Strong gravitational lensing of gravitational waves in Einstein Telescope
Piórkowska, Aleksandra; Biesiada, Marek [Department of Astrophysics and Cosmology, Institute of Physics, University of Silesia, Uniwersytecka 4, 40-007 Katowice (Poland); Zhu, Zong-Hong, E-mail: aleksandra.piorkowska@us.edu.pl, E-mail: marek.biesiada@us.edu.pl, E-mail: zhuzh@bnu.edu.cn [Department of Astronomy, Beijing Normal University, Beijing 100875 (China)
2013-10-01
Gravitational wave experiments have entered a new stage which gets us closer to the opening a new observational window on the Universe. In particular, the Einstein Telescope (ET) is designed to have a fantastic sensitivity that will provide with tens or hundreds of thousand NS-NS inspiral events per year up to the redshift z = 2. Some of such events should be gravitationally lensed by intervening galaxies. We explore the prospects of observing gravitationally lensed inspiral NS-NS events in the Einstein telescope. Being conservative we consider the lens population of elliptical galaxies. It turns out that depending on the local insipral rate ET should detect from one per decade detection in the pessimistic case to a tens of detections per year for the most optimistic case. The detection of gravitationally lensed source in gravitational wave detectors would be an invaluable source of information concerning cosmography, complementary to standard ones (like supernovae or BAO) independent of the local cosmic distance ladder calibrations.
Determining an asymptotically AdS Einstein spacetime from data on its conformal boundary
Enciso, Alberto
Determining an asymptotically AdS Einstein spacetime from data on its conformal boundary Alberto of the AdS/CFT correspondence in string theory is the holographic prescription problem for Einstein metrics and to discuss its physical implications. PACS numbers: 04.20.Ex, 04.20.Ha, 11.25.Tq Keywords: AdS metrics
The Einstein Database of IPC Xray Observations of Optically and Radio
Wilkes, Belinda
The Einstein Database of IPC XÂray Observations of Optically and Radio Selected Quasars. 1 Belinda February 22, 1995 Abstract We present the first volume of the Einstein quasar database. The database to provide a uniform database for general use by the astronomical community. We use the database to extend
Linear "ship waves" generated in stationary flow of a Bose-Einstein condensate past an obstacle
Linear "ship waves" generated in stationary flow of a Bose-Einstein condensate past an obstacle Yu-Einstein condensate past an obstacle. It is shown that these "ship waves" are generated outside the Mach cone]). At last, the sta- tionary waves generated by supersonic flow of BEC past obstacles have been recently
Colliding and Moving Bose-Einstein Condensates: Studies of superfluidity and optical tweezers for condensate transport by Ananth P. Chikkatur Submitted to the Department of Physics in partial fulfillment Bose-Einstein Condensates: Studies of superfluidity and optical tweezers for condensate transport
The critical velocity for vortex existence in a two dimensional rotating Bose-Einstein condensate
Ignat, Radu
The critical velocity for vortex existence in a two dimensional rotating Bose-Einstein condensate-Einstein condensate. It consists in minimizing a Gross-Pitaevskii functional defined in R2 under the unit mass constraint. We estimate the critical rotational speed 1 for vortex existence in the bulk of the condensate
Amplification of Local Instabilities in a Bose-Einstein Condensate with Attractive Interactions
Amplification of Local Instabilities in a Bose-Einstein Condensate with Attractive Interactions Our current understanding of the collapse of Bose-Einstein condensates (BECs) with attractive interactions is incomplete. Previous experiment studied very small condensates where the attractive mean field energy µ
Interaction-induced quantum ratchet in a Bose-Einstein condensate Dario Poletti,1
Li, Baowen
Interaction-induced quantum ratchet in a Bose-Einstein condensate Dario Poletti,1 Giuliano Benenti August 2007 We study the dynamics of a dilute Bose-Einstein condensate confined in a toroidal trap condensates BECs of dilute gases has opened new opportunities for the study of dynamical systems in the pres
Diffractive Nonlinear Geometrical Optics for Variational Wave Equations and the Einstein Equations
Giuseppe Ali; John K. Hunter
2005-11-02
We derive an asymptotic solution of the vacuum Einstein equations that describes the propagation and diffraction of a localized, large-amplitude, rapidly-varying gravitational wave. We compare and contrast the resulting theory of strongly nonlinear geometrical optics for the Einstein equations with nonlinear geometrical optics theories for variational wave equations.
Boyer, Edmond
The 2nd order coherence of superradiance from a BoseEinstein condensate R. Lopes, A. Imanaliev, M have measured the 2-particle correlation function of atoms from a BoseEinstein condensate
Ken-ichiroh Yoshino; Takao Aoki; Akira Furusawa
2006-09-15
Continuous-wave light beams with broadband Einstein-Podolsky-Rosen correlation (Einstein-Podolsky-Rosen beams) are created with two independent squeezed vacua generated by two periodically-poled lithium niobate waveguides and a half beam splitter.
On the m t dependence of the BoseEinstein effect Raluca Muresan a , Oxana Smirnova b , Bengt Lorstad
Smirnova, Oxana
On the m t dependence of the BoseEinstein effect Raluca Mure¸san a , Oxana Smirnova b , Bengt L)1997 Abstract A study of the BoseEinstein correlation function for JETSET 7.4 generated data is performed. Two the string decay and pions from the resonance decays. The dependence of the shape of the output BoseEinstein
Recanati, Catherine
A finite element method with mesh adaptivity for computing vortex states in fastrotating BoseEinstein Abstract Numerical computations of stationary states of fastrotating BoseEinstein condensates require rotation rates). Key words: Gross--Pitaevskii equation, finite element method, mesh adaptivity, BoseEinstein
Addendum to Distinguishing Spins in Decay Chains at the Large Hadron Collider.
Athanasiou, Christiana; Lester, Christopher G; Smillie, Jennifer M; Webber, Bryan R
ar X iv :h ep -p h/ 06 06 21 2v 1 2 0 Ju n 20 06 Preprint typeset in JHEP style - PAPER VERSION Cavendish–HEP–06/15 Addendum to “Distinguishing Spins in Decay Chains at the Large Hadron Collider”? Christiana Athanasiou1, Christopher G. Lester2... such points, we have as M ?? M logR? i KLi(T, S) ? N , (2.6) which is the Monte Carlo equivalent of eq. (1.2). Results for R = 1000 and M = 5 × 107 are shown in table 4. By comparing with tables 1-3, we see that, as might be expected, – 2 – the three...
Smillie, Jennifer M; Webber, Bryan R
ar X iv :h ep -p h/ 05 07 17 0v 3 2 1 Fe b 20 07 Preprint typeset in JHEP style - PAPER VERSION Cavendish–HEP–05/11 Distinguishing Spins in Supersymmetric and Universal Extra Dimension Models at the Large Hadron Collider? Jennifer M. Smillie1... lepton mass distribution 8 4.6 Observable quark-lepton correlations 9 5. Production cross sections 11 6. Experimental observables 13 7. Conclusions 15 A. Quark + far lepton correlation 16 B. UED production cross sections 17 1. Introduction The search...
Neural networks using two-component Bose-Einstein condensates
Tim Byrnes; Shinsuke Koyama; Kai Yan; Yoshihisa Yamamoto
2012-11-16
The authors previously considered a method solving optimization problems by using a system of interconnected network of two component Bose-Einstein condensates (Byrnes, Yan, Yamamoto New J. Phys. 13, 113025 (2011)). The use of bosonic particles was found to give a reduced time proportional to the number of bosons N for solving Ising model Hamiltonians by taking advantage of enhanced bosonic cooling rates. In this paper we consider the same system in terms of neural networks. We find that up to the accelerated cooling of the bosons the previously proposed system is equivalent to a stochastic continuous Hopfield network. This makes it clear that the BEC network is a physical realization of a simulated annealing algorithm, with an additional speedup due to bosonic enhancement. We discuss the BEC network in terms of typical neural network tasks such as learning and pattern recognition and find that the latter process may be accelerated by a factor of N.
Bose-Einstein condensation in liquid 4He under pressure
Glyde, Henry R; Omar Diallo, Souleymane; Azuah, Richard T; Kirichek, Oleg; Taylor, Jon W.
2011-01-01
We present neutron scattering measurements of Bose-Einstein condensation, the atomic momen- tum distribution and Final State effects in liquid 4He under pressure. The condensate fraction at low temperature is found to decrease from n0 = 7.25 0.75% at SVP (p 0) to n0 = 3.2 0.75% at pressure p = 24 bar. This indicates an n0 = 3.0% in the liquid at the liquid/solid co-existence line (p = 25.3 bar). The atomic momentum distribution n(k) has high occupation of low k states and differs significantly from a Gaussian (e.g. a classical n(k)). Both n(k) and the Final state function broaden with increasing pressure, reflecting the increased localization of the 4He in space under increased pressure.
Atomic quantum corrals for Bose-Einstein condensates
Xiong Hongwei [State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071 (China); Kavli Institute for Theoretical Physics China, Chinese Academy of Sciences, Beijing 100190 (China); Wu Biao [Kavli Institute for Theoretical Physics China, Chinese Academy of Sciences, Beijing 100190 (China); International Center for Quantum Materials, Peking University, Beijing 100871 (China); Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China)
2010-11-15
We consider the dynamics of Bose-Einstein condensates in a corral-like potential. Compared to the electronic quantum corrals, the atomic quantum corrals have the advantages of allowing direct and convenient observation of the wave dynamics, together with adjustable interaction strength. Our numerical study shows that these advantages not only allow exploration of the rich dynamical structures in the density distribution but also make the corrals useful in many other aspects. In particular, the corrals for atoms can be arranged into a stadium shape for the experimental visualization of quantum chaos, which has been elusive with electronic quantum corrals. The density correlation is used to describe quantitatively the dynamical quantum chaos. Furthermore, we find that the interatomic interaction can greatly enhance the dynamical quantum chaos, for example, inducing a chaotic behavior even in circle-shaped corrals.
Optical computing with soliton trains in Bose-Einstein condensates
Florian Pinsker
2014-11-18
Optical computing devices can be implemented based on controlled generation of soliton trains in single and multicomponent Bose-Einstein condensates (BEC). Our concepts utilize the phenomenon that the frequency of soliton trains in BEC can be governed by changing interactions within the atom cloud. We use this property to store numbers in terms of those frequencies for a short time until observation. The properties of soliton trains can be changed in an intended way by other components of BEC occupying comparable states or via phase engineering. We elucidate in which sense such an additional degree of freedom can be regarded as a tool for controlled manipulation of data. Finally the outcome of any manipulation made is read out by observing the signature within the density profile.
Bose-Einstein Condensates in the Large Gas Parameter Regime
A. Fabrocini; A. Polls
2001-01-25
Bose-Einstein condensates of 10$^4$ $^{85}$Rb atoms in a cylindrical trap are studied using a recently proposed modified Gross-Pitaevskii equation. The existence of a Feshbach resonance allows for widely tuning the scattering length of the atoms, and values of the peak gas parameter, $x_{pk}$, of the order of 10$^{-2}$ can be attained. We find large differences between the results of the modified Gross-Pitaevskii and of the standard Thomas-Fermi, and Gross-Pitaevskii equations in this region. The column densities at $z=0$ may differ by as much as $\\sim 30%$ and the half maximum radius by $\\sim 20%$. The scattering lengths estimated by fitting the half maximum radius within different approaches can differ by $\\sim 40%$.
Internal Josephson oscillations for distinct momenta Bose-Einstein condensates
Lim, Lih-King [Institute for Theoretical Physics, Utrecht University, Leuvenlaan 4, 3584 CE Utrecht (Netherlands); Laboratoire de Physique des Solides, CNRS UMR 8502, Universite Paris-Sud, F-91405 Orsay Cedex (France); Troppenz, T.; Morais Smith, C. [Institute for Theoretical Physics, Utrecht University, Leuvenlaan 4, 3584 CE Utrecht (Netherlands)
2011-11-15
The internal Josephson oscillations between an atomic Bose-Einstein condensate (BEC) and a molecular one are studied for atoms in a square optical lattice subjected to a staggered gauge field. The system is described by a Bose-Hubbard model with complex and anisotropic hopping parameters that are different for each species, i.e., atoms and molecules. When the flux per plaquette for each species is small, the system oscillates between two conventional zero-momentum condensates. However, there is a regime of parameters in which Josephson oscillations between a vortex-carrying atomic condensate (finite momentum BEC) and a conventional zero-momentum molecular condensate may be realized. The experimental observation of the oscillations between these qualitatively distinct BEC's is possible with state-of-the-art Ramsey interference techniques.
The Einstein-Podolsky-Rosen Argument and the Bell Inequalities
Szabo, Laszlo E
2007-01-01
In 1935 Einstein, Podolsky, and Rosen (EPR) published an important paper in which they claimed that the whole formalism of quantum mechanics together with what they called "Reality Criterion" imply that quantum mechanics cannot be complete. That is, there must exist some elements of reality that are not described by quantum mechanics. There must be, they concluded, a more complete description of physical reality behind quantum mechanics. There must be a state, a hidden variable, characterizing the state of affairs in the world in more details than the quantum mechanical state, something that also reflects the missing elements of reality. Under some further but quite plausible assumptions, this conclusion implies that in some spin-correlation experiments the measured quantum mechanical probabilities should satisfy particular inequalities (Bell-type inequalities). The paradox consists in the fact that quantum probabilities do not satisfy these inequalities. And this paradoxical fact has been confirmed by severa...
Fast production of Bose-Einstein condensates of metastable Helium
Bouton, Q; Hoendervanger, A L; Nogrette, F; Aspect, A; Westbrook, C I; Clément, D
2015-01-01
We report on the Bose-Einstein condensation of metastable Helium-4 atoms using a hybrid approach, consisting of a magnetic quadrupole and a crossed optical dipole trap. In our setup we cross the phase transition with 2x10^6 atoms, and we obtain pure condensates of 5x10^5 atoms in the optical trap. This novel approach to cooling Helium-4 provides enhanced cycle stability, large optical access to the atoms and results in production of a condensate every 6 seconds - a factor 3 faster than the state-of-the-art. This speed-up will dramatically reduce the data acquisition time needed for the measurement of many particle correlations, made possible by the ability of metastable Helium to be detected individually.
Rapidity Dependence of Bose-Einstein Correlations at SPS energies
Kniege, Stefan
2006-04-11
This article is devoted to results on {pi}-{pi}--Bose-Einstein correlations in central Pb+Pb collisions measured by the NA49 experiment at the CERN SPS. Rapidity as well as transverse momentum dependences of the correlation lengths will be shown for collisions at 20A, 30A, 40A, 80A, and 158A GeV beam energy. Only a weak energy dependence of the radii is observed at SPS energies. The kt-dependence of the correlation lengths as well as the single particle mt-spectra will be compared to model calculations. The rapidity dependence is analysed in a range of 2.5 units of rapidity starting at the center of mass rapidity at each beam energy. The correlation lengths measured in the longitudinally comoving system show only a weak dependence on rapidity.
Bose-Einstein condensation as an alternative to inflation
Das, Saurya
2015-01-01
It was recently shown that gravitons with a very small mass should have formed a Bose-Einstein condensate in the very early Universe, whose density and quantum potential can account for the dark matter and dark energy in the Universe respectively. Here we show that the condensation can also naturally explain the observed large scale homogeneity and isotropy of the Universe. Furthermore gravitons continue to fall into their ground state within the condensate at every epoch, accounting for the observed flatness of space at cosmological distances scales. Finally, we argue that the density perturbations due to quantum fluctuations within the condensate give rise to a scale invariant spectrum. This therefore provides a viable alternative to inflation, which is not associated with the well-known problems associated with the latter.
Holographic Superconductors from Einstein-Maxwell-Dilaton Gravity
Yan Liu; Ya-Wen Sun
2010-07-07
We construct holographic superconductors from Einstein-Maxwell-dilaton gravity in 3+1 dimensions with two adjustable couplings $\\alpha$ and the charge $q$ carried by the scalar field. For the values of $\\alpha$ and $q$ we consider, there is always a critical temperature at which a second order phase transition occurs between a hairy black hole and the AdS RN black hole in the canonical ensemble, which can be identified with the superconducting phase transition of the dual field theory. We calculate the electric conductivity of the dual superconductor and find that for the values of $\\alpha$ and $q$ where $\\alpha/q$ is small the dual superconductor has similar properties to the minimal model, while for the values of $\\alpha$ and $q$ where $\\alpha/q$ is large enough, the electric conductivity of the dual superconductor exhibits novel properties at low frequencies where it shows a "Drude Peak" in the real part of the conductivity.
How real-time cosmology can distinguish between different anisotropic models
Amendola, Luca; Bjælde, Ole Eggers; Valkenburg, Wessel; Wong, Yvonne Y.Y. E-mail: oeb@phys.au.dk E-mail: yvonne.y.wong@unsw.edu.au
2013-12-01
We present a new analysis on how to distinguish between isotropic and anisotropic cosmological models based on tracking the angular displacements of a large number of distant quasars over an extended period of time, and then performing a multipole-vector decomposition of the resulting displacement maps. We find that while the GAIA mission operating at its nominal specifications does not have sufficient angular resolution to resolve anisotropic universes from isotropic ones using this method within a reasonable timespan of ten years, a next-generation GAIA-like survey with a resolution ten times better should be equal to the task. Distinguishing between different anisotropic models is however more demanding. Keeping the observational timespan to ten years, we find that the angular resolution of the survey will need to be of order 0.1 ?as in order for certain rotating anisotropic models to produce a detectable signature that is also unique to models of this class. However, should such a detection become possible, it would immediately allow us to rule out large local void models.
Test of the Stokes-Einstein relation in a two-dimensional Yukawa liquid
Bin Liu; J. Goree
2005-11-08
The Stokes-Einstein relation, relating the diffusion and viscosity coefficients D and eta, is tested in two dimensions. An equilibrium molecular-dynamics simulation was used with a Yukawa pair potential. Regimes are identified where motion is diffusive and D is meaningful. The Stokes-Einstein relation, D ~ kT, was found to be violated near the disordering transition; under these conditions collective particle motion exhibits dynamical heterogeneity. At slightly higher temperatures, however, the Stokes-Einstein relation is valid. These results may be testable in strongly-coupled dusty plasma experiments.
Chikkatur, Ananth P., 1975-
2003-01-01
In this thesis, two different sets of experiments are described. The first is an exploration of the microscopic superfluidity of dilute gaseous Bose-Einstein condensates. The second set of experiments were performed using ...
Yazadjiev, Stoytcho
2015-01-01
We consider the problem for the classification of static and asymptotically flat Einstein-Maxwell-dilaton spacetimes with a photon sphere. It is first proven that the photon spheres in Einstein-Maxwell-dilaton gravity have constant mean and constant scalar curvature. Then we derive some relations between the mean curvature and the physical characteristics of the photon spheres. Using further the symmetries of the dimensionally reduced Einstein-Maxwell-dilaton field equations we show that the lapse function, the electrostatic potential and the dilaton field are functionally dependent in the presence of a photon sphere. Using all this we prove the main classification theorem by explicitly constructing all Einstein-Maxwell-dilaton solutions possessing a non-extremal photon sphere.
Static self-gravitating many-body systems in Einstein gravity
Lars Andersson; Berndt G. Schmidt
2009-05-08
We consider the problem of constructing static, elastic, many-body systems in Einstein gravity. The solutions constructed are deformations of static many-body configurations in Newtonian gravity. No symmetry assumptions are made.
Thermodynamics In Einstein equation, the energy momentum tensor of homogeneous, isotropic
Murayama, Hitoshi
Thermodynamics In Einstein equation, the energy momentum tensor of homogeneous, isotropic fluid using the 1st law of thermodynamics, T = (U/S)V . Since U = V is expressed in terms of the temperature
Amplification of Local Instabilities in a Bose-Einstein Condensate with Attractive Interactions
Chin, J. K.
We study the collapse of large homogeneous Bose-Einstein condensates due to intrinsic attractive interactions. We observe the amplification of a local instability by seeding a momentum state p and suddenly switching the ...
Experiments with Bose-Einstein condensates in a double-well potential
Shin, Yong-Il
2006-01-01
Trapped atom interferometry was demonstrated with Bose-Einstein condensates in an optical double-well trap. Coherent splitting of trapped condensates was performed by deforming an optical single-well potential into a ...
Bose-Einstein condensates in optical lattices : the superfluid to Mott insulator phase transition
Mun, Jongchul
2008-01-01
87Rb Bose Einstein Condensate in 3D optical lattice was studied in the regime of weak interaction(the superfluid phase) and strong interaction(the Mott insulating phase). The stability of superfluid currents was studied ...
Axial quasi-normal modes of Einstein-Gauss-Bonnet-dilaton neutron stars
Blázquez-Salcedo, Jose Luis; Kunz, Jutta; Mojica, Sindy; Navarro-Lérida, Francisco
2015-01-01
We investigate axial quasi-normal modes of realistic neutron stars in Einstein-Gauss-Bonnet-dilaton gravity. We consider 8 realistic equations of state containing nuclear, hyperonic, and hybrid matter. We focus on the fundamental curvature mode and compare the results with those of pure Einstein theory. We observe that the frequency of the modes is increased by the presence of the Gauss-Bonnet-dilaton, while the impact on the damping time is typically smaller. Interestingly, we obtain that universal relations valid in pure Einstein theory still hold for Einstein-Gauss-Bonnet-dilaton gravity, and we propose a method to use these phenomenological relations to constrain the value of the Gauss-Bonnet coupling.
Einstein's Clocks, Poincar's Maps: An Interview with Peter Galison, Donald A. Yerxa
Galison, Peter L.
; and in the U.S. after World War II he made no bones about his unhappiness with McCarthyism, nuclear stockpiling, and many other pillars ofestab- lished politics. Einstein clearly loved to iden- tify himself
Violation of Continuous-Variable Einstein-Podolsky-Rosen Steering with Discrete Measurements
Schneeloch, James
In this Letter, we derive an entropic Einstein-Podolsky-Rosen (EPR) steering inequality for continuous-variable systems using only experimentally measured discrete probability distributions and details of the measurement ...
Addendum to "Distinguishing Spins in Decay Chains at the Large Hadron Collider"
Christiana Athanasiou; Christopher G. Lester; Jennifer M. Smillie; Bryan R. Webber
2006-06-20
We extend our earlier study of spin correlations in the decay chain $D\\to C q$, $C\\to B l^{near}$, $B\\to A l^{far}$, where $A,B,C,D$ are new particles with known masses but undetermined spins, $l^{near}$ and $l^{far}$ are opposite-sign same-flavour charged leptons and $A$ is invisible. Instead of looking at the observable 2- and 3-particle invariant mass distributions separately, we compare the full three-dimensional phase space distributions for all possible spin assignments of the new particles, and show that this enhances their distinguishability using a quantitative measure known as the Kullback-Leibler distance.
Colaboracion de Einstein con los grandes matematicos de la epoca en la teoria de la
Ruiz, Jesús M.
Colaboraci´on de Einstein con los grandes matem´aticos de la ´epoca en la teor´ia de la relatividad las matem´aticas en la Teor´ia de la Relatividad. Para ello estudiaremos la recepci´on dada a dicha teor´ia por los matem´aticos de la ´epoca y su colaboraci´on con Einstein. 1. Conexiones entre las
Dynamical formation of correlations in a Bose-Einstein condensate
Laszlo Erdos; Alessandro Michelangeli; Benjamin Schlein
2008-08-01
We consider the evolution of $N$ bosons interacting with a repulsive short range pair potential in three dimensions. The potential is scaled according to the Gross-Pitaevskii scaling, i.e. it is given by $N^2V(N(x_i-x_j))$. We monitor the behavior of the solution to the $N$-particle Schr\\"odinger equation in a spatial window where two particles are close to each other. We prove that within this window a short scale interparticle structure emerges dynamically. The local correlation between the particles is given by the two-body zero energy scattering mode. This is the characteristic structure that was expected to form within a very short initial time layer and to persist for all later times, on the basis of the validity of the Gross-Pitaevskii equation for the evolution of the Bose-Einstein condensate. The zero energy scattering mode emerges after an initial time layer where all higher energy modes disperse out of the spatial window. We can prove the persistence of this structure up to sufficiently small times before three-particle correlations could develop.
EINSTEIN'S SIGNATURE IN COSMOLOGICAL LARGE-SCALE STRUCTURE
Bruni, Marco; Hidalgo, Juan Carlos; Wands, David
2014-10-10
We show how the nonlinearity of general relativity generates a characteristic nonGaussian signal in cosmological large-scale structure that we calculate at all perturbative orders in a large-scale limit. Newtonian gravity and general relativity provide complementary theoretical frameworks for modeling large-scale structure in ?CDM cosmology; a relativistic approach is essential to determine initial conditions, which can then be used in Newtonian simulations studying the nonlinear evolution of the matter density. Most inflationary models in the very early universe predict an almost Gaussian distribution for the primordial metric perturbation, ?. However, we argue that it is the Ricci curvature of comoving-orthogonal spatial hypersurfaces, R, that drives structure formation at large scales. We show how the nonlinear relation between the spatial curvature, R, and the metric perturbation, ?, translates into a specific nonGaussian contribution to the initial comoving matter density that we calculate for the simple case of an initially Gaussian ?. Our analysis shows the nonlinear signature of Einstein's gravity in large-scale structure.
Emergent gravitational dynamics in relativistic Bose--Einstein condensate
Alessio Belenchia; Stefano Liberati; Arif Mohd
2014-10-22
Analogue models of gravity have played a pivotal role in the past years by providing a test bench for many open issues in quantum field theory in curved spacetime such as the robustness of Hawking radiation and cosmological particle production. More recently, the same models have offered a valuable framework within which current ideas about the emergence of spacetime and its dynamics could be discussed via convenient toy models. In this context, we study here an analogue gravity system based on a relativistic Bose--Einstein condensate. We show that in a suitable limit this system provides not only an example of an emergent spacetime (with a massive and a massless relativistic fields propagating on it) but also that such spacetime is governed by an equation with geometric meaning that takes the familiar form of Nordstr{\\"o}m theory of gravitation. In this equation the gravitational field is sourced by the expectation value of the trace of the effective stress energy tensor of the quasiparticles while the Newton and cosmological constants are functions of the fundamental scales of the microscopic system. This is the first example of analogue gravity in which a Lorentz invariant, geometric theory of semiclassical gravity emerges from an underlying quantum theory of matter in flat spacetime.
Testing outer boundary treatments for the Einstein equations
Oliver Rinne; Lee Lindblom; Mark A. Scheel
2007-07-25
Various methods of treating outer boundaries in numerical relativity are compared using a simple test problem: a Schwarzschild black hole with an outgoing gravitational wave perturbation. Numerical solutions computed using different boundary treatments are compared to a `reference' numerical solution obtained by placing the outer boundary at a very large radius. For each boundary treatment, the full solutions including constraint violations and extracted gravitational waves are compared to those of the reference solution, thereby assessing the reflections caused by the artificial boundary. These tests use a first-order generalized harmonic formulation of the Einstein equations. Constraint-preserving boundary conditions for this system are reviewed, and an improved boundary condition on the gauge degrees of freedom is presented. Alternate boundary conditions evaluated here include freezing the incoming characteristic fields, Sommerfeld boundary conditions, and the constraint-preserving boundary conditions of Kreiss and Winicour. Rather different approaches to boundary treatments, such as sponge layers and spatial compactification, are also tested. Overall the best treatment found here combines boundary conditions that preserve the constraints, freeze the Newman-Penrose scalar Psi_0, and control gauge reflections.
Russell Hulse, the First Binary Pulsar, and Science Education
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
in which to test Albert Einstein's prediction that moving objects emit gravitational waves, as well as other aspects of his general theory of relativity. The discovery was...
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Erez ; Bendikov, Michael ; Koch, Norbert ; Helmholtz-Zentrum fr Materialien und Energie GmbH, Bereich Solarenergieforschung, Albert-Einstein-Strae 15, 12489 Berlin The...
Hays, David C. [United States Army Corps of Engineers, Kansas City, Missouri, 64106 (United States)
2012-07-01
Uranium and thorium processing and milling sites generate wastes (source, byproduct, or technically enhanced naturally occurring material), that contain contaminants that are similar to naturally occurring radioactive material deposits and other industry wastes. This can lead to mis-identification of other materials as Site wastes. A review of methods used by the US Army Corps of Engineers and the Environmental Protection Agency to distinguish Site wastes from potential other sources, enhanced materials, and natural deposits, at three different thorium mills was conducted. Real case examples demonstrate the importance of understanding the methods of distinguishing wastes. Distinguishing between Site wastes and enhanced Background material can be facilitated by establishing and applying a formal process. Significant project cost avoidance may be realized by distinguishing Site wastes from enhanced NORM. Collection of information on other potential sources of radioactive material and physical information related to the potential for other radioactive material sources should be gathered and reported in the Historical Site Assessment. At a minimum, locations of other such information should be recorded. Site decision makers should approach each Site area with the expectation that non site related radioactive material may be present and have a process in place to distinguish from Site and non Site related materials. (authors)
Computer Science Distinguished Lectures 2010-11 http://www.cs.iastate.edu/~colloq/new/dls.shtml
Mayfield, John
Computer Science Distinguished Lectures 2010-11 http relate these efforts to our NSF-sponsored IGERT PhD program in Computational Transportation Science. Ouri/pervasive computing. He received his B.A. degree in mathematics, and his Ph.D. degree in computer science from Courant
Chan, Raymond
Distinguishing coding from non-coding sequences in a prokaryote complete genome based on the global in a complete genome is an important problem in DNA sequence analysis. Their rapid and accurate recognition sequences from the non-coding sequences in a prokaryote complete genome. We select a data set of 51
Kammen, Daniel M.
, including Newsweek, Time, The New York Times, The Guardian, and The Financial Times. Kammen has appearedDANIEL M. KAMMEN Dr. Kammen is the Class of 1935 Distinguished Professor of Energy at the University of California, Berkeley, with parallel appointments in the Energy and Resources Group, the Goldman
Modeling the Cost of Climate Policy: Distinguishing Between Alternative Cost Deftitions and Long. There are alternative definitions of cost and the evolution of technologies and preferences is a complex and highly, some are more useful." To be more useful, The Energy Journal, Vol. 24, No. 1. CopyrightQ2003
reservoir pro- duction scenarios. For example, Eiken et al. (2000) success- fully detected fluid-saturation life, oil saturation usually decreases, reservoir pressure declines, and gas breakout may occurUsing time-lapse seismics as a reservoir-monitoring tool, geophysics can help distinguish different
Distinguished Lecture in International Justice and Human Rights Prince Zeid Ra'ad Zeid Al-Hussein
Snider, Barry B.
Distinguished Lecture in International Justice and Human Rights Prince Zeid Ra'ad Zeid Al Brandeis University was honored to host His Royal Highness Prince Zeid Ra'ad Zeid Al Life with the generous support of the Planethood Foundation. Prince Zeid was introduced by Donald
Eligibility | U.S. DOE Office of Science (SC)
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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 submitKansas NuclearElectronic Structure andEligibility Albert Einstein Distinguished
Observation of Fractional Stokes-Einstein Behavior in the Simplest Hydrogen-bonded Liquid
Herwig, Kenneth W; Molaison, Jamie J; Fernandez-Alonso, F.; Bermejo, F. J.; Turner, John F. C.; McLain, Sylvia E.
2007-01-01
Quasielastic neutron scattering has been used to investigate the single-particle dynamics of hydrogen fluoride across its entire liquid range at ambient pressure. For T > 230 K, translational diffusion obeys the celebrated Stokes-Einstein relation, in agreement with nuclear magnetic resonance studies. At lower temperatures, we find significant deviations from the above behavior in the form of a power law with exponent xi = -0.71+/-0.05. More striking than the above is a complete breakdown of the Debye-Stokes-Einstein relation for rotational diffusion. Our findings provide the first experimental verification of fractional Stokes-Einstein behavior in a hydrogen-bonded liquid, in agreement with recent computer simulations.
Quasispherical gravitational collapse in 5D Einstein-Gauss-Bonnet gravity
Ghosh, Sushant G.; Jhingan, S.
2010-07-15
We obtain a general five-dimensional quasispherical collapsing solutions of irrotational dust in Einstein gravity with the Gauss-Bonnet combination of quadratic curvature terms. These solutions are a generalization, to Einstein-Gauss-Bonnet gravity, of the five-dimensional quasispherical Szkeres like collapsing solutions in general relativity. It is found that the collapse proceeds in the same way as in the analogous spherical collapse, i.e., there exists regular initial data such that the collapse proceed to form naked singularities violating cosmic censorship conjecture. The effect of Gauss-Bonnet quadratic curvature terms on the formation and locations of the apparent horizon is deduced.
The Second Law in 4D Einstein-Gauss-Bonnet Gravity
Saugata Chatterjee; Maulik Parikh
2015-01-21
The topological contribution to black hole entropy of a Gauss-Bonnet term in four dimensions opens up the possibility of a violation of the second law of thermodynamics in black hole mergers. We show, however, that the second law is not violated in the regime where Einstein-Gauss-Bonnet holds as an effective theory and black holes can be treated thermodynamically. For mergers of AdS black holes, the second law appears to be violated even in Einstein gravity; we argue, however, that the second law holds when gravitational potential energy is taken into account.
Frequency depending permittivity of the Coulomb system with Bose-Einstein condensate
V. B. Bobrov; S. A. Trigger
2015-09-24
The second-order singularity is found in the low-frequency region of the permittivity of a homogeneous and isotropic system of charged particles consisting of electrons and boson nuclei. This singularity is caused by the existence of a Bose-Einstein condensate for nuclei. The result obtained leads to the existence of the "nuclei superconductivity", which can be experimentally verified in superfluid He II. The results of the proposed an experiment can be considered as a direct proof of the existence of a Bose-Einstein condensate in superfluid He II.
Arne Goedeke; Alan D. Rendall
2010-02-21
It is known that all spatially homogeneous solutions of the vacuum Einstein equations in four dimensions which exist for an infinite proper time towards the future are future geodesically complete. This paper investigates whether the analogous statement holds in higher dimensions. A positive answer to this question is obtained for a large class of models which can be studied with the help of Kaluza-Klein reduction to solutions of the Einstein-scalar field equations in four dimensions. The proof of this result makes use of a criterion for geodesic completeness which is applicable to more general spatially homogeneous models.
Band, Yehuda B.
Statistics of atomic populations in output coupled wave packets from Bose-Einstein condensates for Theoretical Physics, Polish Academy of Sciences, Al. LotnikoÂ´w 32/46, 02-668 Warsaw, Poland 2 Departments waves or output coupled wave packets produced by Bragg scattering from Bose-Einstein condensates BECs
Nore, Caroline
2004-01-01
C. R. Physique 5 (2004) 38 BoseEinstein condensates: recent advances in collective effects/Avancées récentes sur les effets collectifs dans les condensats de BoseEinstein Boundary layers in Gross ; Superfluidité ; Couches limites et obstacles 1. Introduction Since the first experimental observations of BoseEinstein
Pyrak-Nolte, Laura J.
Theory of Bose-Einstein Condensation Nuclear Fusion for Hydrogen-Metal System Yeong E. Kim Department of Bose-Einstein condensation nuclear fusion (BECNF) is used to carry out theoretical analyses of recent on the theory of Bose-Einstein condensation nuclear fusion (BECNF) in micro/nano-scale metal particles [1
Radiation to atom quantum mapping by collective recoil in a BoseEinstein condensate
Paris, Matteo G. A.
Radiation to atom quantum mapping by collective recoil in a BoseEinstein condensate Matteo G a scheme to realize radiation to atom continuous variable quantum mapping, i.e., to teleport the quantum a novel scheme to realize radiation to atom quantum state mapping, Optics Communications 227 (2003) 349
QUATERNIONIC KAHLER AND SPIN(7) METRICS ARISING FROM QUATERNIONIC CONTACT EINSTEIN STRUCTURES
Vassilev, Dimiter N.
QUATERNIONIC KÂ¨AHLER AND SPIN(7) METRICS ARISING FROM QUATERNIONIC CONTACT EINSTEIN STRUCTURES L construct left invariant quaternionic contact (qc) structures on Lie groups with zero and non-zero torsion, equipped with a certain qc structure, has a quaternionic KÂ¨ahler metric as well as a metric with holonomy
Einstein static universe on the brane supported by extended Chaplygin gas
Y. Heydarzade; F. Darabi; K. Atazadeh
2015-11-10
We study the cosmological models in which an extended Chaplygin gas universe is merged with the braneworld scenario. In particular, we examine the realization of Einstein static universe in these models and perform a detailed perturbation analysis. We extract the stability conditions and find their impacts on the geometric equation of state parameter and the spatial curvature of the universe.
Complex Langevin simulation of quantum vortices in a Bose-Einstein condensate
Tomoya Hayata; Arata Yamamoto
2015-11-04
The ab-initio simulation of quantum vortices in a Bose-Einstein condensate is performed by adopting the complex Langevin techniques. We simulate the nonrelativistic boson field theory at finite chemical potential under rotation. In the superfluid phase, vortices are generated above a critical angular velocity and the circulation is clearly quantized even in the presence of quantum fluctuations.
Towards an improved test of Bose-Einstein statistics for photons
Pines, Alexander
Towards an improved test of Bose-Einstein statistics for photons Damon Brown , Dmitry Budker for photons obtained earlier (D. P. DeMille, D. Budker, N. Derr, and E. Deveney, Phys. Rev. Lett. 83(20), 1378 technique. We also discuss the ultimate limits that one can hope to obtain with this degenerate two-photon
Coherent atom-trimer conversion in a repulsive Bose-Einstein condensate
H. Jing; J. Cheng; P. Meystre
2007-03-26
We show that the use of a generalized atom-molecule dark state permits the enhanced coherent creation of triatomic molecules in a repulsive atomic Bose-Einstein condensate, with further enhancement being possible in the case of heteronuclear trimers via the constructive interference between two chemical reaction channels.
Towards a Landau-Zener formula for an interacting Bose-Einstein condensate
D. Witthaut; E. M. Graefe; H. J. Korsch
2006-02-20
We consider the Landau-Zener problem for a Bose-Einstein condensate in a linearly varying two-level system, for the full many-particle system as well and in the mean-field approximation. The many-particle problem can be solved approximately within an independent crossings approximation, which yields an explicit Landau-Zener formula.
Bose–Einstein correlations of ?^0 pairs from hadronic Z^0 decays
Wilson, Graham Wallace; OPAL Collaboration; Abbiendi, G.; Ainsley, C.; Å kesson, P.F.; Alexander, G.; Allison, J.; Amaral, P.; Anagnostou, G.; Anderson, K.J.; Arcelli, S.; Asai, S.; Axen, D.
2003-05-01
We observe Bose–Einstein correlations in ?^0 pairs using back-to-back two jet hadronic events from Z^0 decays in the data sample collected by the OPAL detector at LEP 1 from 1991 to 1995. Using a static Gaussian picture for the pion emitter source...
August 18, September 16, October 11, 2010 Philosophy in Einstein's Science
, Einstein's writings in physics and philosophy enjoyed a commanding presence in the new movements in modern's adopting an empiricist theory of concepts in order to legitimate an extraordinary new physical proposal examiner in Bern seeking to make a few extra Francs by offering tutorials in physics. Maurice Solovine
Synthesize Neutron-Drip-Line-Nuclides with Free-Neutron Bose-Einstein Condensates Experimentally
Bao-Guo Dong
2014-09-22
We first show a possible way to create a new type of matter, free-neutron Bose-Einstein condensate by the ultracold free-neutron-pair Bose-Einstein condensation and then determine the neutron drip line experimentally. The Bose-Einstein condensation of bosonic and fermionic atoms in atomic gases was performed experimentally and predicted theoretically early. Neutrons are similar to fermionic atoms. We found free neutrons could be cooled to ultracold neutrons with very low energy by other colder neutral atoms which are cooled by the laser. These neutrons form neutron pairs with spin zero, and then ultracold neutron-pairs form Bose-Einstein condensate. Our results demonstrate how these condensates can react with accelerated ion beams at different energy to synthesize very neutron-rich nuclides near, on or/and beyond the neutron drip line, to determine the neutron drip line and whether there are long-life nuclide or isomer islands beyond the neutron drip line experimentally. Otherwise, these experimental results will confirm our prediction that is in the whole interacting region or distance of nuclear force in all energy region from zero to infinite, Only repulsive nuclear force exists among identical nucleons and only among different nucleons exists attractive nuclear force.
Synthesize Neutron-Drip-Line-Nuclides with Free-Neutron Bose-Einstein Condensates Experimentally
Dong, Bao-Guo
2014-01-01
We first show a possible way to create a new type of matter, free-neutron Bose-Einstein condensate by the ultracold free-neutron-pair Bose-Einstein condensation and then determine the neutron drip line experimentally. The Bose-Einstein condensation of bosonic and fermionic atoms in atomic gases was performed experimentally and predicted theoretically early. Neutrons are similar to fermionic atoms. We found free neutrons could be cooled to ultracold neutrons with very low energy by other colder neutral atoms which are cooled by the laser. These neutrons form neutron pairs with spin zero, and then ultracold neutron-pairs form Bose-Einstein condensate. Our results demonstrate how these condensates can react with accelerated ion beams at different energy to synthesize very neutron-rich nuclides near, on or/and beyond the neutron drip line, to determine the neutron drip line and whether there are long-life nuclide or isomer islands beyond the neutron drip line experimentally. Otherwise, these experimental results ...
Thermodynamics of a higher dimensional noncommutative anti-de Sitter-Einstein-Born-infeld black hole
Angélica González; Román Linares; Marco Maceda; Oscar Sánchez-Santos
2015-08-21
We analyze noncommutative deformations of a higher dimensional anti-de Sitter-Einstein-Born-Infeld black hole. Two models based on noncommutative inspired distributions of mass and charge are discussed and their thermodynamical properties are calculated. In the (3+1)-dimensional case, the equation of state and the Gibbs energy function of each model are found.
Quasi-Local Energy Conservation Law Derived From The Einstein's Equations
Jong Hyuk Yoon
1998-06-19
The quasi-local energy conservation law is derived from the vacuum Einstein's equations on the timelike boundary surface in the canonical (2,2)-formalism of general relativity. The quasi-local energy and energy flux integral agree with the standard results in the asymptotically flat limit and in spherically symmetric spacetimes.
Mean-field regime of trapped dipolar Bose-Einstein condensates in ...
2010-10-25
Oct 26, 2010 ... Bose-Einstein condensates with arbitrary polarization angle. We show how the ... in three dimensions and at zero temperature [5]. Neglecting the kinetic ... dipolar BEC is determined by a modified contact interaction term and a ... the wave function ?(r,t) of the gas is governed by the GPE. [5,18,42] i¯h?t ?(r ...
Distinguishability Recall A deterministic finite automaton is a five-tuple M = (S, , T, s0, F)
Dunham, Doug
define the multi-step transition function T : S × S as follows. 1. For any s S, T (s, ) = s . 2. For any s S, x and a , T (s, xa) = T(T (s, x), a) . A string x is accepted by M if T (s0, x) F. Definition For any language L over , and any x, y, z , we say x and y are distinguished by z wrt L
General Chair Albert Levi, Sabanci
Boyd, Colin
Finance Chair Karen Decker, ICST Local Chair Erkay Savas, Sabanci University, Turkey Webmaster Chairs Can will be judged based on their quality through double-blind reviewing, where the identities of the authors
General network theory rka albert
Albert, Réka
beconstructedonthesaurisuchasroget's,whichincludesover29,000wordsclassifiedinto 1000 semantic categories. roget's thesaurus Figure 3. Bipartite graph of a thesaurus-based semantic network (top) and its unipartite pro- jection
Representative Albert R. Public Policy
Sibille, Etienne
District. During the last 12 years, he served on the powerful House Energy and Commerce Committee, most of the Subcommittee on Energy and Air Quality. While on Energy and Commerce, Representative Wynn also served OF CONCENTRATION Energy Representative Wynn helped craft the Energy Independence and Security Act of 2007. He added
Albert Carnesale | 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| DepartmentAL/FALGeologic CO2 Storage | DepartmentThe
Dorfman, Konstantin E.
2010-07-14
In this dissertation, I have studied theoretical problems in statistical physics and electrodynamics of Bose particles, namely, mesoscopic effects in statistics of Bose- Einstein condensate (BEC) of atoms and electromagnetic ...
Vacuum solutions with nontrivial boundaries for the Einstein-Gauss-Bonnet theory
Gustavo Dotti; Julio Oliva; Ricardo Troncoso
2008-09-30
The classification of certain class of static solutions for the Einstein-Gauss-Bonnet theory in vacuum is presented. The spacelike section of the class of metrics under consideration is a warped product of the real line with a nontrivial base manifold. For arbitrary values of the Gauss-Bonnet coupling, the base manifold must be Einstein with an additional scalar restriction. The geometry of the boundary can be relaxed only when the Gauss-Bonnet coupling is related with the cosmological and Newton constants, so that the theory admits a unique maximally symmetric solution. This additional freedom in the boundary metric allows the existence of three main branches of geometries in the bulk, containing new black holes and wormholes in vacuum.
Salvatore Antoci
2008-03-25
A particular exact solution of Einstein's Hermitian theory of relativity is examined, after recalling that there is merit in adding phenomenological sources to the theory, and in choosing the metric like it was done long ago by Kursunoglu and Hely. It is shown by intrinsic arguments, relying on the properties of the chosen metric manifold, that the solution describes in Einstein's theory the field of n thin parallel wires at rest, run by steady electric currents, and predicts their equilibrium positions through the injunction that the metric must display cylindrical symmetry in the infinitesimal neighbourhood of each wire. In the weak field limit the equilibrium positions coincide with the ones prescribed by Maxwell's electrodynamics.
Dynamics of Anisotropic Collapsing Spheres in Einstein Gauss-Bonnet Gravity
G. Abbas; M. Zubair
2015-03-06
This paper is devoted to investigate the dynamics of the self gravitating adiabatic and anisotropic source in $5D$ Einstein Gauss-Bonnet gravity. To this end, the source has been taken as Tolman-Bondi model which preserve inhomogeneity in nature. The field equations, Misner-Sharp mass and dynamical equations have formulated in Einstein Gauss-Bonnet gravity in $5D$. The junction conditions have been explored between the anisotropic source and vacuum solution in Gauss-Bonnet gravity in detail. The Misner and Sharp approach has been applied to define the proper time and radial derivatives. Further, these helps to formulate general dynamical equations. The equations show that the mass of the collapsing system increases with the same amount as the effective radial pressure increases. The dynamical system preserve retardation which implies that system under-consideration goes to gravitational collapse.
Dark matter as a ghost free conformal extension of Einstein theory
Barvinsky, A.O.
2014-01-01
We discuss ghost free models of the recently suggested mimetic dark matter theory. This theory is shown to be a conformal extension of Einstein general relativity. Dark matter originates from gauging out its local Weyl invariance as an extra degree of freedom which describes a potential flow of the pressureless perfect fluid. For a positive energy density of this fluid the theory is free of ghost instabilities, which gives strong preference to stable configurations with a positive scalar curvature and trace of the matter stress tensor. Instabilities caused by caustics of the geodesic flow, inherent in this model, serve as a motivation for an alternative conformal extension of Einstein theory, based on the generalized Proca vector field. A potential part of this field modifies the inflationary stage in cosmology, whereas its rotational part at the post inflationary epoch might simulate rotating flows of dark matter.
Examples of naked singularity formation in higher-dimensional Einstein-vacuum spacetimes
An, Xinliang; Lü, H
2015-01-01
The vacuum Einstein equations in 5+1 dimensions are shown to admit solutions describing naked singularity formation in gravitational collapse from nonsingular asymptotically locally flat initial data. We present a class of specific examples with spherical extra dimensions. Thanks to the Kaluza-Klein dimensional reduction, these spacetimes are constructed by lifting continuously self-similar solutions of the 4-dimensional Einstein-scalar field system with a negative exponential potential. Their existence provides a new test-bed for weak cosmic censorship in higher-dimensional gravity. In addition, we point out why a similar attempt of embedding Christodoulou's well-known solutions for massless scalar fields fails to capture formation of naked singularities in 4+1 dimensions.
Can the Stark-Einstein law resolve the measurement problem from an animate perspective?
Fred H. Thaheld
2015-08-14
Analysis of the Stark-Einstein law as it applies to the retinal molecule, which is part of the rhodopsin molecule within the rod cells of the retina, reveals that it may provide the solution to the measurement problem from an animate perspective. That it represents a natural boundary where the Schroedinger equation or wave function automatically goes from linear to nonlinear while remaining in a deterministic state. It will be possible in the near future to subject this theory to empirical tests as has been previously proposed. This analysis provides a contrast to the many decades well studied and debated inanimate measurement problem and would represent an addition to the Stark-Einstein law involving information carried by the photon.
Static Axisymmetric Einstein Equations in Vacuum: Symmetry, New Solutions and Ricci Solitons
Akbar, M M
2015-01-01
An explicit one-parameter Lie point symmetry of the four-dimensional vacuum Einstein equations with two commuting hypersurface-orthogonal Killing vector fields is presented. The parameter takes values over all of the real line and the action of the group can be effected algebraically on any solution of the system. This enables one to construct particular one-parameter extended families of axisymmetric static solutions and cylindrical gravitational wave solutions from old ones, in a simpler way than most solution-generation techniques, including the prescription given by Ernst for this system. As examples, we obtain the families that generalize the Schwarzschild solution and the $C$-metric. These in effect superpose a Levi-Civita cylindrical solution on the seeds. Exploiting a correspondence between static solutions of Einstein's equations and Ricci solitons (self-similar solutions of the Ricci flow), this also enables us to construct new steady Ricci solitons.
Bose-Einstein condensate coupled to a nanomechanical resonator on an atom chip
Philipp Treutlein; David Hunger; Stephan Camerer; Theodor W. Hänsch; Jakob Reichel
2007-10-04
We theoretically study the coupling of Bose-Einstein condensed atoms to the mechanical oscillations of a nanoscale cantilever with a magnetic tip. This is an experimentally viable hybrid quantum system which allows one to explore the interface of quantum optics and condensed matter physics. We propose an experiment where easily detectable atomic spin-flips are induced by the cantilever motion. This can be used to probe thermal oscillations of the cantilever with the atoms. At low cantilever temperatures, as realized in recent experiments, the backaction of the atoms onto the cantilever is significant and the system represents a mechanical analog of cavity quantum electrodynamics. With high but realistic cantilever quality factors, the strong coupling regime can be reached, either with single atoms or collectively with Bose-Einstein condensates. We discuss an implementation on an atom chip.
Thermodynamics of FRW universe in Einstein and Quasi-Topological Cosmology
Moradpour, H
2015-01-01
By applying the unified first law of thermodynamics on the apparent horizon of FRW universe, we get the entropy relations for the apparent horizon in both Einstein and quasi-topological gravity theories.Throughout the paper, the results of considering the Hayward-Kodama and Cai-Kim temperatures are also addressed. Our study shows that a dark energy candidate and its interaction with other parts of cosmos in a FRW universe with arbitrary curvature parameter affect the horizon entropy and thus the Bekenstein term in the Einstein theory. Whenever, there is no energy exchange between the material and other parts of cosmos, we get an expression for the apparent horizon entropy in quasi-topological gravity, which is in agreement with other attempts followed different approaches. The effects of a mutual interaction between the material and geometrical parts of cosmos on the apparent horizon entropy and the validity of second law of thermodynamics in quasi-topological gravity are also perused.
Imprint of modified Einstein's gravity on white dwarfs: Unifying type Ia supernovae
Das, Upasana
2015-01-01
We establish the importance of modified Einstein's gravity (MG) in white dwarfs (WDs) for the first time in the literature. We show that MG leads to significantly sub- and super-Chandrasekhar limiting mass WDs, depending on a single model parameter. However, conventional WDs on approaching Chandrasekhar's limit are expected to trigger type Ia supernovae (SNeIa), a key to unravel the evolutionary history of the universe. Nevertheless, observations of several peculiar, under- and over-luminous SNeIa argue for the limiting mass widely different from Chandrasekhar's limit. Explosions of MG induced sub- and super-Chandrasekhar limiting mass WDs explain under- and over-luminous SNeIa respectively, thus unifying these two apparently disjoint sub-classes. Our discovery questions both the global validity of Einstein's gravity and the uniqueness of Chandrasekhar's limit.
Bose-Einstein Interference in the Passage of a Jet in a Dense Medium
Cheuk-Yin Wong
2012-04-16
When a jet collides coherently with many parton scatterers at very high energies, the Bose-Einstein symmetry with respect to the interchange of the virtual bosons leads to a destructive interference of the Feynman amplitudes in most regions of the momentum transfer phase space but a constructive interference in some other regions of the momentum transfer phase space. As a consequence, the recoiling scatterers have a tendency to come out collectively along the incident jet direction, each carrying a substantial fraction of the incident jet longitudinal momentum. The manifestation of the Bose-Einstein interference as collective recoils of the scatterers along the jet direction may have been observed in angular correlations of hadrons associated with a high-pT trigger in high-energy heavy-nuclei collisions at RHIC and LHC.
Bose-Einstein condensate of metastable helium for quantum correlation experiments
Michael Keller; Mateusz Kotyrba; Florian Leupold; Mandip Singh; Maximilian Ebner; Anton Zeilinger
2015-01-05
We report on the realization of Bose-Einstein condensation of metastable helium-4. After exciting helium to its metastable state in a novel pulse-tube cryostat source, the atomic beam is collimated and slowed. We then trap several 10^8 atoms in a magneto-optical trap. For subsequent evaporative cooling, the atoms are transferred into a magnetic trap. Degeneracy is achieved with typically a few 10^6 atoms. For detection of atomic correlations with high resolution, an ultrafast delay-line detector has been installed. Consisting of four quadrants with independent readout electronics that allow for true simultaneous detection of atoms, the detector is especially suited for quantum correlation experiments that require the detection of correlated subsystems. We expect our setup to allow for the direct demonstration of momentum entanglement in a scenario equivalent to the Einstein-Podolsky-Rosen gedanken experiment. This will pave the way to matter-wave experiments exploiting the peculiarities of quantum correlations.
5D Super Yang-Mills on $Y^{p,q}$ Sasaki-Einstein manifolds
Jian Qiu; Maxim Zabzine
2015-02-27
On any simply connected Sasaki-Einstein five dimensional manifold one can construct a super Yang-Mills theory which preserves at least two supersymmetries. We study the special case of toric Sasaki-Einstein manifolds known as $Y^{p,q}$ manifolds. We use the localisation technique to compute the full perturbative part of the partition function. The full equivariant result is expressed in terms of certain special function which appears to be a curious generalisation of the triple sine function. As an application of our general result we study the large $N$ behaviour for the case of single hypermultiplet in adjoint representation and we derive the $N^3$-behaviour in this case.
Temperature jump in degenerate quantum gases in the presence of a Bose - Einstein condensate
A. V. Latyshev; A. A. Yushkanov
2010-01-04
We construct a kinetic equation modeling the behavior of degenerate quantum Bose gases whose collision rate depends on the momentum of elementary excitations. We consider the case where the phonon component is the decisive factor in the elementary excitations. We analytically solve the half-space boundary value problem of the temperature jump at the boundary of the degenerate Bose gas in the presence of a Bose -- Einstein condensate.
Squeezing and entanglement of density oscillations in a Bose-Einstein condensate
Andrew C. J. Wade; Jacob F. Sherson; Klaus Mølmer
2015-04-16
The dispersive interaction of atoms and a far-detuned light field allows nondestructive imaging of the density oscillations in Bose-Einstein condensates. Starting from a ground state condensate, we investigate how the measurement back action leads to squeezing and entanglement of the quantized density oscillations. In particular, we show that properly timed, stroboscopic imaging and feedback can be used to selectively address specific eigenmodes and avoid excitation of non-targeted modes of the system.
Controlling chaos in the Bose-Einstein condensate system of a double lattice
Wang Zhixia, E-mail: wzx2007111@126.com; Ni Zhengguo; Cong Fuzhong [Aviation University of Air Force (China); Liu Xueshen [Jilin University, Institute of Atomic and Molecular Physics (China); Chen Lei [Aviation University of Air Force (China)
2011-02-15
We study the chaotic dynamics in the Bose-Einstein condensate (BEC) system of a double lattice. Chaotic space-time evolution is investigated for the particle number density in a BEC. By changing of the s-wave scattering length with a Feshbach resonance, the chaotic behavior can be well controlled to enter into periodicity. Numerical calculation shows that there is periodic orbit according to the s-wave scattering length only if the maximal Lyapunov exponent of the system is negative.
Controlling chaos in a Bose-Einstein condensate loaded into a moving optical lattice potential
Wang Zhixia [Aviation University of the Air Force (China)], E-mail: wzx2007111@126.com; Zhang Xihe; Shen Ke [Changchun University of Science and Technology, Department of Physics (China)
2008-11-15
The spatial structure of a Bose-Einstein condensate loaded into an optical lattice potential is investigated, and spatially chaotic distributions of the condensates are revealed. By means of changing of the s-wave scattering length with a Feshbach resonance, the chaotic behavior can be well controlled to enter into periodicity. Numerical simulation shows that there are different periodic orbits according to different s-wave scattering lengths only if the maximal Lyapunov exponent of the system is negative.
Flambaum, V V
2015-01-01
The Lorentz invariance and Einstein equivalence principle violating effects in the narrow 7.8 eV transition in 229Th nucleus may be 100 000 times larger than in atoms. This transition may be investigated using high precision laser spectroscopy methods, has a very small width, and suppressed systematic effects. Similar values of the effects are expected in 73 eV 235U nuclear transition which is coming within the reach of the laser spectroscopy. Mossbauer transitions give another possibility.
Bose–Einstein condensation versus Dicke–Hepp–Lieb transition in an optical cavity
Piazza, Francesco; Strack, Philipp; Zwerger, Wilhelm
2013-12-15
We provide an exact solution for the interplay between Bose–Einstein condensation and the Dicke–Hepp–Lieb self-organization transition of an ideal Bose gas trapped inside a single-mode optical cavity and subject to a transverse laser drive. Based on an effective action approach, we determine the full phase diagram at arbitrary temperature, which features a bi-critical point where the transitions cross. We calculate the dynamically generated band structure of the atoms and the associated suppression of the critical temperature for Bose–Einstein condensation in the phase with a spontaneous periodic density modulation. Moreover, we determine the evolution of the polariton spectrum due to the coupling of the cavity photons and the atomic field near the self-organization transition, which is quite different above or below the Bose–Einstein condensation temperature. At low temperatures, the critical value of the Dicke–Hepp–Lieb transition decreases with temperature and thus thermal fluctuations can enhance the tendency to a periodic arrangement of the atoms. -- Highlights: •Atoms inside a driven cavity can undergo two transitions: self-organization and BEC. •The phase diagram has four phases which coexist at a bi-critical point. •Atom–cavity coupling creates a dynamical lattice for the atoms. •Finite temperature can enhance the tendency towards self-organization. •We calculate the detailed spectrum of the polaritonic excitations.
Bose-Einstein Condensation versus Dicke-Hepp-Lieb Transition in an Optical Cavity
Francesco Piazza; Philipp Strack; Wilhelm Zwerger
2013-05-13
We provide an exact solution for the interplay between Bose-Einstein condensation and the Dicke-Hepp-Lieb self-organization transition of an ideal Bose gas trapped inside a single-mode optical cavity and subject to a transverse laser drive. Based on an effective action approach, we determine the full phase diagram at arbitrary temperature, which features a bi-critical point where the transitions cross. We calculate the dynamically generated band structure of the atoms and the associated supression of the critical temperature for Bose-Einstein condensation in the phase with a spontaneous periodic density modulation. Moreover, we determine the evolution of the polariton spectrum due to the coupling of the cavity photons and the atomic field near the self-organization transition, which is quite different above or below the Bose-Einstein condensation temperature. At low temperatures, the critical value of the Dicke-Hepp-Lieb transition decreases with temperature and thus thermal fluctuations can enhance the tendency to a periodic arrangement of the atoms.
Einstein-Born-Infeld black holes with a scalar hair in three-dimensions
S. Habib Mazharimousavi; M. Halilsoy
2015-07-28
We present black hole solutions in $2+1-$dimensional Einstein's theory of gravity coupled with Born-Infeld nonlinear electrodynamic and a massless self-interacting scalar field. The model has five free parameters: mass $M$, cosmological constant $\\ell $, electric $q$ and scalar $r_{0}$ charges and Born-Infeld parameter $\\beta $. To attain exact solution for such a highly non-linear system we adjust, i.e. finely tune, the parameters of the theory with the integration constants. In the limit $\\beta \\rightarrow 0$ we recover the results of Einstein-Maxwell-Scalar theory, obtained before. The self interacting potential admits finite minima apt for the vacuum contribution. Hawking temperature of the model is investigated versus properly tuned parameters. By employing this tuned-solution as basis, we obtain also a dynamic solution which in the proper limit admits the known solution in Einstein gravity coupled with self-interacting scalar field. Finally we establish the equations of a general scalar-tensor field coupled to nonlinear electrodynamics field\\ in $2+1-$dimensions without searching for exact solutions.
On Einstein - Weyl unified model of dark energy and dark matter
A. T. Filippov
2009-05-29
Here I give a more detailed account of the part of the conference report that was devoted to reinterpreting the Einstein `unified models of gravity and electromagnetism' (1923) as the unified theory of dark energy (cosmological constant) and dark matter (neutral massive vector particle having only gravitational interactions). After summarizing Einstein's work and related earlier work of Weyl and Eddington, I present an approach to finding spherically symmetric solutions of the simplest variant of the Einstein models that was earlier mentioned in Weyl's work as an example of his generalization of general relativity. The spherically symmetric static solutions and homogeneous cosmological models are considered in some detail. As the theory is not integrable we study approximate solutions. In the static case, we show that there may exist two horizons and derive solutions near horizons. In cosmology, we propose to study the corresponding expansions of possible solutions near the origin and derive these expansions in a simplified model neglecting anisotropy. The structure of the solutions seems to hint at a possibility of an inflation mechanism that does not require adding scalar fields.
AdS and Lifshitz Black Holes in Conformal and Einstein-Weyl Gravities
H. Lu; Y. Pang; C. N. Pope; J. Vazquez-Poritz
2012-04-14
We study black hole solutions in extended gravities with higher-order curvature terms, including conformal and Einstein-Weyl gravities. In addition to the usual AdS vacuum, the theories admit Lifshitz and Schr\\"odinger vacua. The AdS black hole in conformal gravity contains an additional parameter over and above the mass, which may be interpreted as a massive spin-2 hair. By considering the first law of thermodynamics, we find that it is necessary to introduce an associated additional intensive/extensive pair of thermodynamic quantities. We also obtain new Liftshitz black holes in conformal gravity and study their thermodynamics. We use a numerical approach to demonstrate that AdS black holes beyond the Schwarzschild-AdS solution exist in Einstein-Weyl gravity. We also demonstrate the existence of asymptotically Lifshitz black holes in Einstein-Weyl gravity. The Lifshitz black holes arise at the boundary of the parameter ranges for the AdS black holes. Outside the range, the solutions develop naked singularities. The asymptotically AdS and Lifshitz black holes provide an interesting phase transition, in the corresponding boundary field theory, from a relativistic Lorentzian system to a non-relativistic Lifshitz system.
Energy of Einstein's static universe and its implications for the ?CDM cosmology
Mitra, Abhas, E-mail: amitra@barc.gov.in [Astrophysical Sciences Division, Bhabha Atomic Research Centre, Mumbai-400085 (India)
2013-03-01
The total Einstein energy (P{sub 0}) of a homogeneous and isotropic universe can be computed by using an appropriate superpotential (Rosen 1994) and also by a direct method (Mitra 2010). Irrespective of the physical significance of P{sub 0}, its eventual numerical value must be same in both the cases because both are derived from the same Einstein pseudo tensor and by employing the same coordinates. It follows then that the static isotropic and homogeneous universe, i.e., Einstein's static universe (ESU), must have an infinite radius and which tantamounts to a spatially flat case. The physical significance of this result is that the cosmological constant, ?, is actually zero and ESU is the vacuous Minkowski spacetime. It is the same result which has recently been obtained in a completely independent manner (Mitra, Bhattacharyya and Bhatt 2013). Thus even though, mathematically, one can conceive of a static 3-sphere for the foundation of relativistic cosmology, physically, no such 3-sphere exists. On the other hand, the spatial section of the universe could essentially be an Euclidean space with local curvature spikes due to presence of lumpy matter. Since the ''Dark Energy'' is associated with ? in the ?CDM model, the result obtained here suggests that it is an artifact of departure of the lumpy and fractal universe from the ideal Friedmann Robertson Walker model (Jackson et al. 2012, Cowley et al. 2013)
Deformed Horava-Lifshitz Cosmology and Stability of Einstein Static Universe
Y. Heydarzade; M. Khodadi; F. Darabi
2015-02-16
Stability of the Einstein static universe versus the linear scalar, vector and tensor perturbations is investigated in the context of deformed Ho\\v{r}ava-Lifshitz cosmology inspired by entropic force scenario. A general stability condition against the linear scalar perturbations is obtained. Using this general condition, it is shown that there is no stable Einstein static universe for the case of flat universe, $k=0$. For the the special case of large values of running parameter of HL gravity $\\omega$, in a positively curved universe $k>0$, the domination of the quintessence and phantom matter fields with barotropic equation of state parameter $\\betauniverse $k -\\frac{1}{3}$ are needed to be the dominant fields of the universe. Also, a neutral stability against the vector perturbations is obtained. Finally, an inequality including the cosmological parameters of the Einstein static universe is obtained for the stability against the tensor perturbations. It turns out that for large $\\omega$ values, there is a stability against the tensor perturbations.
Five-dimensional black strings in Einstein-Gauss-Bonnet gravity
Kobayashi, Tsutomu; Tanaka, Takahiro
2005-04-15
We consider black-string-type solutions in five-dimensional Einstein-Gauss-Bonnet gravity. Numerically constructed solutions under static, axially symmetric and translationally invariant metric ansatz are presented. The solutions are specified by two asymptotic charges: mass of a black string and a scalar charge associated with the radion part of the metric. Regular black string solutions are found if and only if the two charges satisfy a fine-tuned relation, and otherwise the spacetime develops a singular event horizon or a naked singularity. We can also generate bubble solutions from the black strings by using a double Wick rotation.
Interaction of half-quantized vortices in two-component Bose-Einstein condensates
Eto, Minoru; Kasamatsu, Kenichi; Nitta, Muneto; Takeuchi, Hiromitsu; Tsubota, Makoto
2011-06-15
We study the asymptotic interaction between two half-quantized vortices in two-component Bose-Einstein condensates. When two vortices in different components are placed at distance 2R, the leading order of the force between them is found to be (lnR/{xi}-1/2)/R{sup 3}, in contrast to 1/R between vortices placed in the same component. We derive it analytically using the Abrikosov ansatz and the profile functions of the vortices, confirmed numerically with the Gross-Pitaevskii model. We also find that the short-range cutoff of the intervortex potential linearly depends on the healing length.
On the detectability of quantum radiation in Bose-Einstein condensates
Ralf Schützhold
2006-05-04
Based on doubly detuned Raman transitions between (meta) stable atomic or molecular states and recently developed atom counting techniques, a detection scheme for sound waves in dilute Bose-Einstein condensates is proposed whose accuracy might reach down to the level of a few or even single phonons. This scheme could open up a new range of applications including the experimental observation of quantum radiation phenomena such as the Hawking effect in sonic black-hole analogues or the acoustic analogue of cosmological particle creation. PACS: 03.75.Kk, 04.70.Dy, 42.65.Dr.
Dynamical generation of phase-squeezed states in two-component Bose-Einstein condensates
Jin, G. R.; An, Y.; Yan, T.; Lu, Z. S. [Department of Physics, Beijing Jiaotong University, Beijing 100044 (China)
2010-12-15
As an ''input'' state of a linear (Mach-Zehnder or Ramsey) interferometer, the phase-squeezed state proposed by Berry and Wiseman exhibits the best sensitivity approaching to the Heisenberg limit [Phys. Rev. Lett. 85, 5098 (2000)]. Similar with the Berry and Wiseman's state, we find that two kinds of phase-squeezed states can be generated dynamically with atomic Bose-Einstein condensates confined in a symmetric double-well potential, which shows squeezing along spin operator S{sub y} and antisqueezing along S{sub z}, leading to subshot-noise phase estimation.
Dynamical tunneling of a Bose-Einstein condensate in periodically driven systems
R. K. Shrestha; J. Ni; W. K. Lam; G. S. Summy; S. Wimberger
2013-09-13
We report measurements of dynamical tunneling rates of a Bose-Einstein condensate across a barrier in classical phase space. The atoms are initially prepared in quantum states that extend over a classically regular island region. We focus on the specific system of quantum accelerator modes of the kicked rotor in the presence of gravity. Our experimental data is supported by numerical simulations taking into account imperfections mainly from spontaneous emission. Furthermore, we predict experimentally accessible parameter ranges over which direct tunneling could be readily observed if spontaneous emission was further suppressed. Altogether, we provide a proof-of-principle for the experimental accessibility of dynamical tunneling rates in periodically driven systems.
Fast frictionless dynamics as a toolbox for low-dimensional Bose-Einstein condensates
A. del Campo
2011-11-17
A method is proposed to implement a fast frictionless dynamics in a low-dimensional Bose-Einstein condensate by engineering the time-dependence of the transverse confining potential in a highly anisotropic trap. The method exploits the inversion of the dynamical self-similar scaling law in the radial degrees of freedom. We discuss the application of the method to preserve short-range correlations in time of flight experiments, the implementation of nearly-sudden quenches of non-linear interactions, and its power to assist self-similar dynamics in quasi-one dimensional condensates.
Quantum decoherence of an anharmonic oscillator monitored by a Bose-Einstein condensate
D. Alonso; S. Brouard; D. Sokolovski
2014-10-28
The dynamics of a quantum anharmonic oscillator whose position is monitored by a Bose-Einstein condensate (BEC) trapped in a symmetric double well potential is studied. The (non-exponential) decoherence induced on the oscillator by the measuring device is analysed. A detailed quasiclassical and quantum analysis is presented. In the first case, for an arbitrary initial coherent state, two different decoherence regimes are observed: An initial Gaussian decay followed by a power law decay for longer times. The characteristic time scales of both regimes are reported. Analytical approximated expressions are obtained in the full quantum case where algebraic time decay of decoherence is observed.
Axion Bose-Einstein Condensation: a model beyond Cold Dark Matter
Yang, Q
2010-01-01
Cold dark matter axions form a Bose-Einstein condensate if the axions thermalize. Recently, it was found that they do thermalize when the photon temperature reaches T ~ 100 eV(f/10^12GeV)^1/2 and that they continue to do so thereafter. We discuss the differences between axion BEC and CDM in the linear regime and the non-linear regime of evolution of density perturbations. We find that axion BEC provides a mechanism for the production of net overall rotation in dark matter halos, and for the alignment of cosmic microwave anisotropy multi-poles.
Axion Bose-Einstein Condensation: a model beyond Cold Dark Matter
Q. Yang
2010-04-15
Cold dark matter axions form a Bose-Einstein condensate if the axions thermalize. Recently, it was found that they do thermalize when the photon temperature reaches T ~ 100 eV(f/10^12GeV)^1/2 and that they continue to do so thereafter. We discuss the differences between axion BEC and CDM in the linear regime and the non-linear regime of evolution of density perturbations. We find that axion BEC provides a mechanism for the production of net overall rotation in dark matter halos, and for the alignment of cosmic microwave anisotropy multi-poles.
Boundary Effects on Bose-Einstein Condensation in Ultra-Static Space-Times
L. Akant; E. Ertugrul; Y. Gul; O. T. Turgut
2015-05-13
The boundary effects on the Bose-Einstein condensation of a Bose gas with a nonvanishing chemical potential on an ultra-static space-time are studied. High temperature regime, which is the relevant regime for the relativistic gas, is studied through the heat kernel expansion for both Dirichlet and Neumann boundary conditions. The high temperature expansion in the presence of a chemical potential is generated via the Mellin transform methods as applied to the harmonic sums representing the free energy and the depletion coefficient. The effects of boundary conditions on the relation between depletion coefficient and temperature are analyzed. The analysis is done for both charged and neutral bosons.
Black Holes with Scalar Hairs in Einstein-Gauss-Bonnet Gravity
Y. Brihaye; L. Ducobu
2015-11-21
The Einstein-Gauss-Bonnet gravity in five dimensions is extended by scalar fields and the corresponding equations are reduced to a system of non-linear differential equations. A large family of regular solutions of these equations is shown to exist. Generically, these solutions are spinning black holes with scalar hairs. They can be characterized (but not uniquely) by an horizon and an angular velocity on this horizon. Taking particular limits the black holes approach boson star or become extremal, in any case the limiting configurations remain hairy.
Black Holes with Scalar Hairs in Einstein-Gauss-Bonnet Gravity
Brihaye, Y
2015-01-01
The Einstein-Gauss-Bonnet gravity in five dimensions is extended by scalar fields and the corresponding equations are reduced to a system of non-linear differential equations. A large family of regular solutions of these equations is shown to exist. Generically, these solutions are spinning black holes with scalar hairs. They can be characterized (but not uniquely) by an horizon and an angular velocity on this horizon. Taking particular limits the black holes approach boson star or become extremal, in any case the limiting configurations remain hairy.
R. J. van den Hoogen
2009-09-01
A formalism for analyzing the complete set of field equations describing Macroscopic Gravity is presented. Using this formalism, a cosmological solution to the Macroscopic Gravity equations is determined. It is found that if a particular segment of the connection correlation tensor is zero and if the macroscopic geometry is described by a flat Robertson-Walker metric, then the effective correction to the averaged Einstein Field equations of General Relativity i.e., the backreaction, is equivalent to a positive spatial curvature term. This investigation completes the analysis of [Phys. Rev. Lett., vol. 95, 151102, (2005)] and the formalism developed provides a possible basis for future studies.
Single-atom aided probe of the decoherence of a Bose-Einstein condensate
H. T. Ng; S. Bose
2008-02-22
We study a two-level atom coupled to a Bose-Einstein condensate. We show that the rules governing the decoherence of mesoscopic superpositions involving different classical-like states of the condensate can be probed using this system. This scheme is applicable irrespective of whether the condensate is initially in a coherent, thermal or more generally in any mixture of coherent states. The effects of atom loss and finite temperature to the decoherence can therefore be studied. We also discuss the various noise sources causing the decoherence.
Alexey Novikov; Mikhail Ovchinnikov
2008-05-27
In this paper we considered a quantum particle moving through delute Bose-Einstein condensate at zero temperature. In our formulation the impurity particle interacts with the gas of uncoupled Bogoliubov's excitations. We constructed the perturbation theory for the Green's function of the impurity particle with respect to the impurity-condensate interaction employing the coherent-state path integral approach. The perturbative expansion for the Green's function is resumed into the expansion for its poles with the help of the diagrammatic technique developed in this work. The dispersion relation for the impurity clothed by condensate excitations is obtained and effective mass is evaluated beyond the Golden rule approximation.
Modified uncertainty principle from the free expansion of a Bose-Einstein Condensate
Elías Castellanos; Celia Escamilla-Rivera
2015-09-21
We develop a theoretical and numerical analysis of the free expansion of a Bose-Einstein condensate, in which we assume that the single particle energy spectrum is deformed due to a possible quantum structure of space time. Also we consider the presence of inter particle interactions in order to study more realistic and specific scenarios. The modified free velocity expansion of the condensate leads in a natural way to a modification of the uncertainty principle, which allows us to investigate some possible features of the Planck scale regime in low-energy earth-based experiments.
Toric data and Killing forms on homogeneous Sasaki-Einstein manifold $T^{1,1}$
Vladimir Slesar; Mihai Visinescu; Gabriel Eduard Vilcu
2015-03-02
Throughout this paper we investigate the complex structure of the conifold $C(T^{1,1})$ basically making use of the interplay between symplectic and complex approaches of the K\\"{a}hler toric manifolds. The description of the Calabi-Yau manifold $C(T^{1,1})$ using toric data allows us to write explicitly the complex coordinates and apply standard methods for extracting special Killing forms on the base manifold. As an outcome, we obtain the complete set of special Killing forms on the five-dimensional Sasaki-Einstein space $T^{1,1}$.
Jain, Piyush; Cinti, Fabio; Boninsegni, Massimo [Department of Physics, University of Alberta, Edmonton, Alberta (Canada)
2011-07-01
Low-temperature properties of harmonically confined two-dimensional assemblies of dipolar bosons are systematically investigated by Monte Carlo simulations. Calculations carried out for different numbers of particles and strengths of the confining potential yield evidence of a quantum phase transition from a superfluid to a crystal-like phase, consistently with what is observed in the homogeneous system. It is found that the crystal phase nucleates in the center of the trap, as the density increases. Bose-Einstein condensation vanishes at T=0 upon entering the crystalline phase, concurrently with the disappearance of the superfluid response.
Diffraction of a Bose-Einstein condensate in the time domain
Colombe, Yves; Mercier, Brigitte; Perrin, Helene; Lorent, Vincent
2005-12-15
We have observed the diffraction of a Bose-Einstein condensate of rubidium atoms on a vibrating mirror potential. The matter wave packet bounces back at normal incidence on a blue-detuned evanescent light field after a 3.6 mm free fall. The mirror vibrates at a frequency of 500 kHz with an amplitude of 3 nm. The atomic carrier and side bands are directly imaged during their ballistic expansion. The locations and the relative weights of the diffracted atomic wave packets are in very good agreement with the theoretical prediction of Henkel et al. [J. Phys. II 4, 1877 (1994)].
Energies and damping rates of elementary excitations in spin-1 Bose-Einstein condensed gases
Gergely Szirmai; Peter Szepfalusy; Krisztian Kis-Szabo
2003-05-15
Finite temperature Green's function technique is used to calculate the energies and damping rates of elementary excitations of the homogeneous, dilute, spin-1 Bose gases below the Bose-Einstein condensation temperature both in the density and spin channels. For this purpose the self-consistent dynamical Hartree-Fock model is formulated, which takes into account the direct and exchange processes on equal footing by summing up certain classes of Feynman diagrams. The model is shown to fulfil the Goldstone theorem and to exhibit the hybridization of one-particle and collective excitations correctly. The results are applied to the gases of ^{23}Na and ^{87}Rb atoms.
Comment on ``Ramsey Fringes in a Bose-Einstein Condensate between Atoms and Molecules''
Eric Braaten; H. -W. Hammer; M. Kusunoki
2003-01-24
In Phys. Rev. Lett. 89, 180401 (2002) [cond-mat/0204504], Kokkelmans and Holland interpret the results of a recent experiment at JILA that demonstrated atom-molecule coherence in a Bose-Einstein condensate. Using a mean-field approximation to a resonance field theory involving an atom condensate and a molecular condensate, they find that the molecular condensate is tiny compared to the atom condensate. We show that if the probability for the molecular field to create a diatomic molecule is correctly included, the numbers of atoms in the atom condensate and in the condensate of diatomic molecules are comparable.
Efimov States in a Bose-Einstein Condensate near a Feshbach Resonance
Eric Braaten; H. -W. Hammer; M. Kusunoki
2003-05-11
Recent experiments with Bose-Einstein condensates of 85Rb atoms near a Feshbach resonance have produced evidence for a condensate of diatomic molecules coexisting with the atom condensate. It should also be possible to create condensates of the triatomic molecules predicted by Efimov coexisting with the atom and dimer condensates. The smoking gun for the trimer condensate would be oscillatory dependence of observables on the binding energy of the trimer. It may also be possible to deduce the existence of the trimer condensate from the spectra of the bursts of atoms and dimers created in the disappearance of the trimers.
Anderson Localization of Expanding Bose-Einstein Condensates in Random Potentials
Sanchez-Palencia, L.; Clement, D.; Lugan, P.; Bouyer, P.; Aspect, A. [Laboratoire Charles Fabry de l'Institut d'Optique, CNRS and Univ. Paris-Sud, Campus Polytechnique, RD 128, F-91127 Palaiseau cedex (France); Shlyapnikov, G. V. [Laboratoire de Physique Theorique et Modeles Statistiques, Univ. Paris-Sud, F-91405 Orsay cedex (France); Van der Waals-Zeeman Institute, Univ. Amsterdam, Valckenierstraat 65/67, 1018 XE Amsterdam (Netherlands)
2007-05-25
We show that the expansion of an initially confined interacting 1D Bose-Einstein condensate can exhibit Anderson localization in a weak random potential with correlation length {sigma}{sub R}. For speckle potentials the Fourier transform of the correlation function vanishes for momenta k>2/{sigma}{sub R} so that the Lyapunov exponent vanishes in the Born approximation for k>1/{sigma}{sub R}. Then, for the initial healing length of the condensate {xi}{sub in}>{sigma}{sub R} the localization is exponential, and for {xi}{sub in}<{sigma}{sub R} it changes to algebraic.
Bose-Einstein condensates in the presence of a magnetic trap and optical lattice
Kapitula, Todd; Kevrekidis, P.G. [Department of Mathematics and Statistics, University of New Mexico, Albuquerque, New Mexico 87131 (United States); Department of Mathematics and Statistics, University of Massachusetts, Amherst, Massachusetts 01003-4515 (United States)
2005-09-01
In this paper we consider solutions of a nonlinear Schroedinger equation with a parabolic and a periodic potential motivated from the dynamics of Bose-Einstein condensates. Our starting point is the corresponding linear problem which we analyze through regular perturbation and homogenization techniques. We then use Lyapunov-Schmidt theory to establish the persistence and bifurcation of the linear states in the presence of attractive and repulsive nonlinear inter-particle interactions. Stability of such solutions is also examined and a count is given of the potential real, complex and imaginary eigenvalues with negative Krein signature that such solutions may possess. The results are corroborated with numerical computations.
Collapses and Revivals of Bose-Einstein Condensates Formed in Small Atomic Samples
Wright, E.M.; Walls, D.F.; Garrison, J.C.
1996-09-01
The macroscopic wave function for atomic samples composed of a few thousand particles is shown to exhibit collapses and revivals on a few seconds time scale, while Bose-Einstein condensation remains in the form of off-diagonal long-range order in the one-particle reduced density matrix. A recently proposed measurement scheme which is sensitive to Bose-broken gauge symmetry, and hence to the macroscopic wave function, could be used to detect the collapses and revivals experimentally. {copyright} {ital 1996 The American Physical Society.}
Gelfond, Michael
Chemical Company at its chemical plant in Pampa, Texas where he was involved in both process plant design University and a group of petrochemical companies jointly established an off-campus graduate degree program. There, he managed research and development projects on the reduction of air pollution from petrochemical
Shahidi Named Distinguished Professor
Sally
2002-08-29
Methods for the Study of Material Interfacial Motions.” The Purdue Mathematics .... Speaking of industrial support, this fall we will welcome several new members
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Po, Lai-Man
of the celebration programmes of CityU's 25th Anniversary Spintronics: Electrons, Spins, Computers and Telephones Abstract: Spintronics is a new field of research which exploits the influence of the electron spin will review some of the most promising directions of today: spin transfer phenomena, spintronics
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Po, Lai-Man
that are necessary for the social acceptability of some proposed solutions such as Carbon Capture and Storage (CCS), wind power, tidal and sea-current energy, and the new generation of nuclear reactors.Apart from
LANL Distinguished Postdoc Fellows
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the mechanisms behind the molecular processes involved in somatic mutagenesis and aging. Bio: Ludmil is co-mentored by William Hlavacek and Thomas Leitner. He previously was...
Zerkle wins Governor's Distinguished
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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-effectWorkingLos Alamos verifies largestnamed Electrochemical SocietyZenoss,wins
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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 | National(TechnicalNISACDisruption WeeklyChavez
Mahdy, M R C; Ding, Weiqiang; Mehmood, M Q; Nieto-Vesperinas, Manuel; Qiu, Cheng-Wei
2015-01-01
To unify and clarify the persistently debated electromagnetic stress tensors (ST) and photon momenta, we establish a theory inspired by the Einstein-Laub formalism inside an arbitrary macroscopic object immersed in any complex medium. Our generalized Einstein-Laub force and ST yield the total force experienced by any generic macroscopic object due to the internal field interacting with its atoms, charges and molecules. Appropriate scenarios are established for the conservation of a newly proposed momentum that we call non-mechanical generalized Einstein-Laub momentum, along with the kinetic and canonical momenta of photons. Our theory remains valid even in a generally heterogeneous or bounded embedding background medium without resorting to hidden momenta, and unambiguously identifies the existence domain, or validity domain, of the STs and photon momenta proposed to date. This existence domain is the region either outside a macroscopic scatterer with only exterior fields, or at its interior with only inside ...
Einstein@Home all-sky search for periodic gravitational waves in LIGO S5 data
Aasi, J; Abbott, B P; Abbott, R; Abbott, T D; Abernathy, M; Accadia, T; Acernese, F; Adams, C; Adams, T; Addesso, P; Adhikari, R; Affeldt, C; Agathos, M; Agatsuma, K; Ajith, P; Allen, B; Allocca, A; Ceron, E Amador; Amariutei, D; Anderson, S B; Anderson, W G; Arai, K; Araya, M C; Ast, S; Aston, S M; Astone, P; Atkinson, D; Aufmuth, P; Aulbert, C; Aylott, B E; Babak, S; Baker, P; Ballardin, G; Ballmer, S; Bao, Y; Barayoga, J C B; Barker, D; Barone, F; Barr, B; Barsotti, L; Barsuglia, M; Barton, M A; Bartos, I; Bassiri, R; Bastarrika, M; Basti, A; Batch, J; Bauchrowitz, J; Bauer, Th S; Bebronne, M; Beck, D; Behnke, B; Bejger, M; Beker, M G; Bell, A S; Bell, C; Belopolski, I; Benacquista, M; Berliner, J M; Bertolini, A; Betzwieser, J; Beveridge, N; Beyersdorf, P T; Bhadbade, T; Bilenko, I A; Billingsley, G; Birch, J; Biswas, R; Bitossi, M; Bizouard, M A; Black, E; Blackburn, J K; Blackburn, L; Blair, D; Bland, B; Blom, M; Bock, O; Bodiya, T P; Bogan, C; Bond, C; Bondarescu, R; Bondu, F; Bonelli, L; Bonnand, R; Bork, R; Born, M; Boschi, V; Bose, S; Bosi, L; Bouhou, B; Braccini, S; Bradaschia, C; Brady, P R; Braginsky, V B; Branchesi, M; Brau, J E; Breyer, J; Briant, T; Bridges, D O; Brillet, A; Brinkmann, M; Brisson, V; Britzger, M; Brooks, A F; Brown, D A; Bulik, T; Bulten, H J; Buonanno, A; Burguet--Castell, J; Buskulic, D; Buy, C; Byer, R L; Cadonati, L; Cagnoli, G; Cagnoli, G; Calloni, E; Camp, J B; Campsie, P; Cannon, K; Canuel, B; Cao, J; Capano, C D; Carbognani, F; Carbone, L; Caride, S; Caudill, S; Cavaglià, M; Cavalier, F; Cavalieri, R; Cella, G; Cepeda, C; Cesarini, E; Chalermsongsak, T; Charlton, P; Chassande-Mottin, E; Chen, W; Chen, X; Chen, Y; Chincarini, A; Chiummo, A; Cho, H S; Chow, J; Christensen, N; Chua, S S Y; Chung, C T Y; Chung, S; Ciani, G; Clara, F; Clark, D E; Clark, J A; Clayton, J H; Cleva, F; Coccia, E; Cohadon, P -F; Colacino, C N; Colla, A; Colombini, M; Conte, A; Conte, R; Cook, D; Corbitt, T R; Cordier, M; Cornish, N; Corsi, A; Costa, C A; Coughlin, M; Coulon, J -P; Couvares, P; Coward, D M; Cowart, M; Coyne, D C; Creighton, J D E; Creighton, T D; Cruise, A M; Cumming, A; Cunningham, L; Cuoco, E; Cutler, R M; Dahl, K; Damjanic, M; Danilishin, S L; D'Antonio, S; Danzmann, K; Dattilo, V; Daudert, B; Daveloza, H; Davier, M; Daw, E J; Day, R; Dayanga, T; De Rosa, R; DeBra, D; Debreczeni, G; Degallaix, J; Del Pozzo, W; Dent, T; Dergachev, V; DeRosa, R; Dhurandhar, S; Di Fiore, L; Di Lieto, A; Di Palma, I; Emilio, M Di Paolo; Di Virgilio, A; Díaz, M; Dietz, A; Dietz, A; Donovan, F; Dooley, K L; Doravari, S; Dorsher, S; Drago, M; Drever, R W P; Driggers, J C; Du, Z; Dumas, J -C; Dwyer, S; Eberle, T; Edgar, M; Edwards, M; Effler, A; Ehrens, P; Endr?czi, G; Engel, R; Etzel, T; Evans, K; Evans, M; Evans, T; Factourovich, M; Fafone, V; Fairhurst, S; Farr, B F; Favata, M; Fazi, D; Fehrmann, H; Feldbaum, D; Ferrante, I; Ferrini, F; Fidecaro, F; Finn, L S; Fiori, I; Fisher, R P; Flaminio, R; Foley, S; Forsi, E; Fotopoulos, N; Fournier, J -D; Franc, J; Franco, S; Frasca, S; Frasconi, F; Frede, M; Frei, M A; Frei, Z; Freise, A; Frey, R; Fricke, T T; Friedrich, D; Fritschel, P; Frolov, V V; Fujimoto, M -K; Fulda, P J; Fyffe, M; Gair, J; Galimberti, M; Gammaitoni, L; Garcia, J; Garufi, F; Gáspár, M E; Gelencser, G; Gemme, G; Genin, E; Gennai, A; Gergely, L Á; Ghosh, S; Giaime, J A; Giampanis, S; Giardina, K D; Giazotto, A; Gil-Casanova, S; Gill, C; Gleason, J; Goetz, E; González, G; Gorodetsky, M L; Goßler, S; Gouaty, R; Graef, C; Graff, P B; Granata, M; Grant, A; Gray, C; Greenhalgh, R J S; Gretarsson, A M; Griffo, C; Grote, H; Grover, K; Grunewald, S; Guidi, G M; Guido, C; Gupta, R; Gustafson, E K; Gustafson, R; Hallam, J M; Hammer, D; Hammond, G; Hanks, J; Hanna, C; Hanson, J; Harms, J; Harry, G M; Harry, I W; Harstad, E D; Hartman, M T; Haughian, K; Hayama, K; Hayau, J -F; Heefner, J; Heidmann, A; Heitmann, H; Hello, P; Hendry, M A; Heng, I S; Heptonstall, A W; Herrera, V; Heurs, M; Hewitson, M; Hild, S; Hoak, D; Hodge, K A; Holt, K; Holtrop, M; Hong, T; Hooper, S; Hough, J; Howell, E J; Hughey, B; Husa, S; Huttner, S H; Huynh-Dinh, T; Ingram, D R; Inta, R; Isogai, T; Ivanov, A; Izumi, K; Jacobson, M; James, E; Jang, Y J; Jaranowski, P; Jesse, E; Johnson, W W; Jones, D I; Jones, R; Jonker, R J G; Ju, L; Kalmus, P; Kalogera, V; Kandhasamy, S; Kang, G; Kanner}, J B; Kasprzack, M; Kasturi, R; Katsavounidis, E; Katzman, W; Kaufer, H; Kaufman, K; Kawabe, K; Kawamura, S; Kawazoe, F; Keitel, D; Kelley, D; Kells, W; Keppel, D G; Keresztes, Z; Khalaidovski, A; Khalili, F Y; Khazanov, E A; Kim, B K; Kim, C; Kim, H; Kim, K; Kim, N; Kim, Y M; King, P J; Kinzel, D L; Kissel, J S; Klimenko, S; Kline, J; Kokeyama, K; Kondrashov, V; Koranda, S; Korth, W Z; Kowalska, I; Kozak, D; Kringel, V; Krishnan, B; Królak, A; Kuehn, G; Kumar, P; Kumar, R; Kurdyumov, R; Kwee, P; Lam, P K; Landry, M; Langley, A; Lantz, B
2012-01-01
This paper presents results of an all-sky searches for periodic gravitational waves in the frequency range [50, 1190] Hz and with frequency derivative ranges of [-2 \\times 10^-9, 1.1 \\times 10^-10] Hz/s for the fifth LIGO science run (S5). The novelty of the search lies in the use of a non-coherent technique based on the Hough-transform to combine the information from coherent searches on timescales of about one day. Because these searches are very computationally intensive, they have been deployed on the Einstein@Home distributed computing project infrastructure. The search presented here is about a factor 3 more sensitive than the previous Einstein@Home search in early S5 LIGO data. The post-processing has left us with eight surviving candidates. We show that deeper follow-up studies rule each of them out. Hence, since no statistically significant gravitational wave signals have been detected, we report upper limits on the intrinsic gravitational wave amplitude h0. For example, in the 0.5 Hz-wide band at 15...
Unified Einstein-Virasoro Master Equation in the General Non-Linear Sigma Model
Boer, J. de; Halpern, M.B.
1996-06-05
The Virasoro master equation (VME) describes the general affine-Virasoro construction $T=L^abJ_aJ_b+iD^a \\dif J_a$ in the operator algebra of the WZW model, where $L^ab$ is the inverse inertia tensor and $D^a $ is the improvement vector. In this paper, we generalize this construction to find the general (one-loop) Virasoro construction in the operator algebra of the general non-linear sigma model. The result is a unified Einstein-Virasoro master equation which couples the spacetime spin-two field $L^ab$ to the background fields of the sigma model. For a particular solution $L_G^ab$, the unified system reduces to the canonical stress tensors and conventional Einstein equations of the sigma model, and the system reduces to the general affine-Virasoro construction and the VME when the sigma model is taken to be the WZW action. More generally, the unified system describes a space of conformal field theories which is presumably much larger than the sum of the general affine-Virasoro construction and the sigma model with its canonical stress tensors. We also discuss a number of algebraic and geometrical properties of the system, including its relation to an unsolved problem in the theory of $G$-structures on manifolds with torsion.
Thermodynamics of rotating black branes in (n+1)-dimensional Einstein-Born-Infeld gravity
Dehghani, M. H.; Sedehi, H. R. Rastegar
2006-12-15
We construct a new class of charged rotating solutions of (n+1)-dimensional Einstein-Born-Infeld gravity with cylindrical or toroidal horizons in the presence of cosmological constant and investigate their properties. These solutions are asymptotically (anti)-de Sitter and reduce to the solutions of Einstein-Maxwell gravity as the Born-Infeld parameters goes to infinity. We find that these solutions can represent black branes, with inner and outer event horizons, an extreme black brane or a naked singularity provided the parameters of the solutions are chosen suitably. We compute temperature, mass, angular momentum, entropy, charge and electric potential of the black brane solutions. We obtain a Smarr-type formula and show that these quantities satisfy the first law of thermodynamics. We also perform a stability analysis by computing the heat capacity and the determinant of Hessian matrix of mass of the system with infinite boundary with respect to its thermodynamic variables in both the canonical and the grand-canonical ensembles, and show that the system is thermally stable in the whole phase space. Also, we find that there exists an unstable phase when the finite size effect is taken into account.
Einstein-Aether Theory as an Alternative to Dark Energy Model?
Meng, Xin-He
2011-01-01
In the Einstein-aether theory by taking a special form of the ${\\cal F}({\\cal K})$ (a free function in this theory) the possibility of Einstein-aether theory as an alternative to dark energy model is discussed in details, that is, taking a special Aether field as a dark energy candidate. We compute the joint statistic constraints on this special model's parameters by using the recent type Ia supernovae (SNe Ia) data, the Cosmic Microwave Background (CMB) shift parameter data, and the Baryonic Acoustic Oscillations (BAOs) data traced by the Sloan Digital Sky Survey (SDSS). Furthermore, we analyze other constrains from the observational Hubble parameter data (OHD). The comparison with the standard cosmological model (cosmological constant $\\Lambda$ Cold Dark Matter ($\\Lambda$CDM) model) is clearly shown with new features; also we discuss an interesting relation between the coupling constant M in this model and the possible existence of a special accelerate scale in the MOdified Newtonian Dynamics (MOND) model i...
Bose-Einstein Condensation and Bose Glasses in an S = 1 Organo-metallic quantum magnet
Zapf, Vivien [Los Alamos National Laboratory
2012-06-01
I will speak about Bose-Einstein condensation (BEC) in quantum magnets, in particular the compound NiCl2-4SC(NH2)2. Here a magnetic field-induced quantum phase transition to XY antiferromagnetism can be mapped onto BEC of the spins. The tuning parameter for BEC transition is the magnetic field rather than the temperature. Some interesting phenomena arise, for example the fact that the mass of the bosons that condense can be strongly renormalized by quantum fluctuations. I will discuss the utility of this mapping for both understanding the nature of the quantum magnetism and testing the thermodynamic limit of Bose-Einstein Condensation. Furthermore we can dope the system in a clean and controlled way to create the long sought-after Bose Glass transition, which is the bosonic analogy of Anderson localization. I will present experiments and simulations showing evidence for a new scaling exponent, which finally makes contact between theory and experiments. Thus we take a small step towards the difficult problem of understanding the effect of disorder on bosonic wave functions.
Propagation of chaos, Wasserstein gradient flows and toric Kahler-Einstein metrics
Robert J. Berman; Magnus Onnheim
2015-06-09
Motivated by a probabilistic approach to Kahler-Einstein metrics we consider a general non-equlibrium statistical mechanics model in Euclidean space consisting of the stochastic gradient flow of a given quasi-convex N particle interaction energy. We show that a deterministic macroscopic evolution equation emerges in the large N-limit of many particles. The proof uses the theory of weak gradient flows on the Wasserstein space and in particular De Georgi's notion of minimizing movements. Applied to the setting of permanental point processes at negative temperature the corresponding limiting evolution equation yields a new drift-diffusion equation, coupled to the Monge-Ampere operator, whose static solutions correspond to toric Kahler-Einstein metrics. This drift-diffusion equation is the gradient flow on the Wasserstein space of probability measures of the K-energy functional in Kahler geometry and it can be seen as a fully non-linear version of various extensively studied dissipative evolution equations and conservations laws, including the Keller-Segal equation and Burger's equation. We also obtain a real probabilistic analog of the complex geometric Yau-Tian-Donaldson conjecture in this setting. In another direction applications to singular pair interactions in 1D are given, leading to sharp convergence results. Complex geometric aspects of these results will be discussed elsewhere.
Recent results on Bose-Einstein correlations by the PHENIX Experiment
Mate Csanad; for the PHENIX Collaboration
2015-03-12
Bose-Einstein momentum correlation functions of identical bosons reveal the shape and size of the (soft) particle emitting source of the given particle. The widths of these correlation functions are called HBT radii, named after Brown and Twiss who studied the angular diameter of stars via intensity correlations in their radio telescopes. Today, high energy physics experiments measure the HBT radii as a function of many parameters: particle type, transverse momentum, azimuthal angle, collision energy, collision geometry. In this paper we present results from the RHIC PHENIX experiment. These include the observation of strong azimuthal-angle dependence of the extracted Gaussian HBT radii, the similarities and differences between kaon and pion HBT radii. The key point of this paper is the application of Bose-Einstein correlations to the search for the critical point: how HBT radii would show the appearance of a first order phase transition, and what the non-monotonic collision energy dependence of the pion source tells us about the critical point; and how the non-Gaussian shape of correlation functions is related to one of the critical exponents.
The Einstein@Home search for radio pulsars and PSR J2007+2722
Allen, B; Cordes, J M; Deneva, J S; Hessels, J W T; Anderson, D; Aulbert, C; Bock, O; Brazier, A; Chatterjee, S; Demorest, P B; Eggenstein, H B; Fehrmann, H; Gotthelf, E V; Hammer, D; Kaspi, V M; Kramer, M; Lyne, A G; Machenschalk, B; McLaughlin, M A; Messenger, C; Pletsch, H J; Ransom, S M; Stairs, I H; Stappers, B W; Bhat, N D R; Bogdanov, S; Camilo, F; Champion, D J; Crawford, F; Desvignes, G; Freire, P C C; Heald, G; Jenet, F A; Lazarus, P; Lee, K J; van Leeuwen, J; Lynch, R; Papa, M A; Prix, R; Rosen, R; Scholz, P; Siemens, X; Stovall, K; Venkataraman, A; Zhu, W
2013-01-01
Einstein@Home aggregates the computer power of hundreds of thousands of volunteers from 192 countries, to search for new neutron stars using data from electromagnetic and gravitational-wave detectors. This paper presents a detailed description of the search for new radio pulsars using PALFA survey data from the Arecibo Observatory. The enormous computing power allows this search to cover a new region of parameter space; it can detect pulsars in binary systems with orbital periods as short as 11 min. We also describe the first Einstein@Home discovery, the 40.8 Hz isolated pulsar PSR J2007+2722, and provide a full timing model. PSR J2007+2722's pulse profile is remarkably wide with emission over almost the entire spin period. This neutron star is most likely a disrupted recycled pulsar, about as old as its characteristic spin-down age of 404 Myr. However there is a small chance that it was born recently, with a low magnetic field. If so, upper limits on the X-ray flux suggest but can not prove that PSR J2007+27...
Meacher, Duncan; Hanna, Chad; Regimbau, Tania; Sathyaprakash, B S
2015-01-01
The Einstein Telescope is a conceived third generation gravitational-wave detector that is envisioned to be an order of magnitude more sensitive than advanced LIGO, Virgo and Kagra, which would be able to detect gravitational-wave signals from the coalescence of compact objects with waveforms starting as low as 1Hz. With this level of sensitivity, we expect to detect sources at cosmological distances. In this paper we introduce an improved method for the generation of mock data and analyse it with a new low latency compact binary search pipeline called gstlal. We present the results from this analysis with a focus on low frequency analysis of binary neutron stars. Despite compact binary coalescence signals lasting hours in the Einstein Telescope sensitivity band when starting at 5 Hz, we show that we are able to discern various overlapping signals from one another. We also determine the detection efficiency for each of the analysis runs conducted and and show a proof of concept method for estimating the numbe...
Dilaton minimally coupled to 2 + 1 Einstein Maxwell fields; stationary cyclic symmetric black holes
A. A. Garcia-Diaz; G. Gutierrez Cano
2014-12-17
Using the Schwarzschild coordinate frame for a static cyclic symmetric metric in 2 + 1 Einstein gravity coupled to a electric Maxwell field and a dilaton logarithmically depending on the radial coordinate in the presence of an exponential potential the general solution of the Einstein Maxwell dilaton equations is derived and it is identified with the Chan Mann charged dilaton solution. Via a general SL(2;R) transformation, applied on the obtained charged dilaton metric, a family of stationary dilaton solutions has been generated; these solutions possess five parameters: dilaton and cosmological constants , charge, momentum, and mass for some values of them. All the exhibited solutions have been characterized by their quasi-local energy, mass, and momentum through their series expansions at spatial infinity. The structural functions determining these solutions increase as the radial coordinate does, hence they do not exhibit an dS AdS behavior at infinity Moreover, the algebraic structure of the Maxwell field, energy-momentum, and Cotton tensors is given explicitly.
Energy distribution of a regular black hole solution in Einstein-nonlinear electrodynamics
I. Radinschi; F. Rahaman; Th. Grammenos; A. Spanou; Sayeedul Islam
2014-07-16
In this work a study about the energy-momentum of a new four-dimensional spherically symmetric, static and charged, regular black hole solution developed in the context of general relativity coupled to nonlinear electrodynamics is presented. Asymptotically, this new black hole solution behaves as the Reissner-Nordstr\\"om solution only for the particular value {\\mu}=4, where {\\mu} is a positive integer parameter appearing in the mass function of the solution. The calculations are performed by use of the Einstein, Landau-Lifshitz, Weinberg and M{\\o}ller energy-momentum complexes. In all the aforesaid prescriptions, the expressions for the energy of the gravitating system considered depend on the mass M of the black hole, its charge q, a positive integer {\\alpha} and the radial coordinate r. In all these pseudotensorial prescriptions the momenta are found to vanish, while the Landau-Lifshitz and Weinberg prescriptions give the same result for the energy distribution. In addition, the limiting behavior of the energy for the cases r tends toward infinity, r=0 and q=0 is studied. The special case {\\mu}=4 and {\\alpha}=3 is also examined. We conclude that the Einstein and M{\\o}ller energy-momentum complexes can be considered as the most reliable tools for the study of the energy-momentum localization of a gravitating system.
Bose-Einstein condensation in dark power-law laser traps
Amine Jaouadi; Naceur Gaaloul; Bruno Viaris De Lesegno; Mourad Telmini; Laurence Pruvost; Eric Charron
2010-09-10
We investigate theoretically an original route to achieve Bose-Einstein condensation using dark power-law laser traps. We propose to create such traps with two crossing blue-detuned Laguerre-Gaussian optical beams. Controlling their azimuthal order $\\ell$ allows for the exploration of a multitude of power-law trapping situations in one, two and three dimensions, ranging from the usual harmonic trap to an almost square-well potential, in which a quasi-homogeneous Bose gas can be formed. The usual cigar-shaped and disk-shaped Bose-Einstein condensates obtained in a 1D or 2D harmonic trap take the generic form of a "finger" or of a "hockey puck" in such Laguerre-Gaussian traps. In addition, for a fixed atom number, higher transition temperatures are obtained in such configurations when compared with a harmonic trap of same volume. This effect, which results in a substantial acceleration of the condensation dynamics, requires a better but still reasonable focusing of the Laguerre-Gaussian beams.
Boyer, Edmond
ccsd-00000333(version2):29Apr2003 Schemes for loading a BoseEinstein condensate into a two results are presented. PACS numbers: 03.75.Fi, 05.30.Jp, 32.80.Pj I. INTRODUCTION BoseEinstein, California 90089-0484, USA We propose two loading mechanisms of a degenerate Bose gas into a surface trap
Topological vortex formation in a Bose-Einstein condensate Following the theoretical suggestion [1], we have demonstrated a new method to create vortices in Bose-Einstein condensates. Vortices were imprinted into the condensate wavefunction using topological phases. Sodium condensates held in an Ioffe
Gammal, Arnaldo
Stabilizing an attractive Bose-Einstein condensate by driving a surface collective mode Arjendu K-Einstein condensates with attractive interatomic interactions undergo collective collapse beyond a critical number. We show theoretically that if the low-lying collective modes of the condensate are excited, the radial
Garnier, Josselin
Collapse BoseEinstein condensate induced by fluctuations laser intensity Garnier* LaboratoireEinstein condensate trapped a system beams analyzed presence small fluctuations intensity. shown that condensate. collapse shows rapid strong shrinking the condensate some critical number of atoms, and accompanied
Sipe,J. E.
Spatial fragmentation of a Bose-Einstein condensate in a double-well potential R. W. Spekkens and J-Einstein condensate with repulsive interparticle interactions in a double-well potential, using a restricted variational principle. Within such an approach, there is a transition from a single condensate to a fragmented
Gammal, Arnaldo
Stabilizing an attractive BoseEinstein condensate by driving a surface collective mode Arjendu K 2001# BoseEinstein condensates with attractive interatomic interactions undergo collective collapse beyond a critical number. We show theoretically that if the lowlying collective modes of the condensate
Chu, Shih-I
2011-01-01
-Einstein condensate through coupling to a superconducting resonator H. T. Ng1 and Shih-I Chu1,2 1 Center for Quantum 23 August 2011) We consider a two-component Bose-Einstein condensate in a double-well potential separated condensates can be generated by evolving to a mixture of dark states via the dissipation
Kheruntsyan, Karen
2014-01-01
PHYSICAL REVIEW A 90, 033613 (2014) Anisotropy in s-wave Bose-Einstein condensate collisions. Boiron,2 C. I. Westbrook,2 and K. V. Kheruntsyan3 1 Institute of Physics, Polish Academy of Sciences process with Bose- Einstein-condensate collisions for which the angular distribution of scattered atom
Scudellaro, Paolo
Einstein Equations and Alternative Lagrangians This article has been downloaded from IOPscience LETTERS Europhys. Lett., 32 (2), pp. 185-190 (1995) 10October 1995 Einstein Equations and Alternative of alternative Lagrangians. After proposing an algebraic test, we apply it to both the cases of minimal
Band, Yehuda B.
Four-wave mixing in Bose-Einstein condensate systems with multiple spin states J. P. Burke, Jr.,* P) We calculate the four-wave mixing (FWM) in a Bose-Einstein condensate system having multiple spin wave packets that are initially overlapping in physical space, but have nonvanishing relative momentum
Jordan, Andrew N.; Ooi, C. H. Raymond; Svidzinsky, Anatoly A.
2006-09-15
The atom fluctuation statistics of an ideal, mesoscopic, Bose-Einstein condensate are investigated from several different perspectives. By generalizing the grand canonical analysis (applied to the canonical ensemble problem), we obtain a self-consistent equation for the mean condensate particle number that coincides with the microscopic result calculated from the laser master equation approach. For the case of a harmonic trap, we obtain an analytic expression for the condensate particle number that is very accurate at all temperatures, when compared with numerical canonical ensemble results. Applying a similar generalized grand canonical treatment to the variance, we obtain an accurate result only below the critical temperature. Analytic results are found for all higher moments of the fluctuation distribution by employing the stochastic path integral formalism, with excellent accuracy. We further discuss a hybrid treatment, which combines the master equation and stochastic path integral analysis with results obtained based on the canonical ensemble quasiparticle formalism [Kocharovsky et al., Phys. Rev. A 61, 053606 (2000)], producing essentially perfect agreement with numerical simulation at all temperatures.
Mike Batzle holds the Baker Hughes Distinguished Chair of Petrophysics and Borehole Geophysics, at the Colorado School of Mines, where he has been a member of the geophysics department for the past 17 years from the University of California, Riverside, and a PhD in geophysics from MIT. His main interests have
Polly, David
." By comparing the physical properties, one can easily distinguish between the two minerals. Pyrite is less dense, sphalerite, as well as other minerals. In Indiana, pyrite can be found in organic-rich shale, coal, and in the production of sulfuric acid. The chemical weathering of pyrite can have undesirable effects in coal mines
J. M. Vogels; K. Xu; W. Ketterle
2002-03-13
By colliding two Bose-Einstein condensates we have observed strong bosonic stimulation of the elastic scattering process. When a weak input beam was applied as a seed, it was amplified by a factor of 20. This large gain atomic four-wave mixing resulted in the generation of two macroscopically occupied pair-correlated atomic beams.
I. Radinschi; Th. Grammenos
2005-08-01
We use Moeller's energy-momentum complex in order to explicitly compute the energy and momentum density distributions for an exact solution of Einstein's field equations with a negative cosmological constant minimally coupled to a static massless scalar field in a static, spherically symmetric background in (2+1)-dimensions.
S. I. Tertychniy
1998-10-18
An example of application of the specialized computer algebra system Grg-EC to the searching for solutions to the source-free Maxwell and Einstein--Maxwell equations is demonstrated. The solution involving five arbitrary functions of two variables is presented in explicit form (up to quadratures). An emphasis is made on the characterizing of the software utilized.
Maria Laura Pucheu; Mauricio Bellini
2010-06-23
We study phantom and inflationary cosmologies using form-invariance transformations of the Einstein equations with respect to $\\rho$, $H$, $a$ and $p$, from a 5D vacuum. Equations of state and squared fluctuations of the inflaton and phantom fields are examined.
Stability of black holes in Einstein-charged scalar field theory in a cavity
Dolan, Sam R; Winstanley, Elizabeth
2015-01-01
Can a black hole that suffers a superradiant instability evolve towards a 'hairy' configuration which is stable? We address this question in the context of Einstein-charged scalar field theory. First, we describe a family of static black hole solutions which possess charged scalar-field hair confined within a mirror-like boundary. Next, we derive a set of equations which govern the linear, spherically symmetric perturbations of these hairy solutions. We present numerical evidence which suggests that, unlike the vacuum solutions, the (single-node) hairy solutions are stable under linear perturbations. Thus, it is plausible that stable hairy black holes represent the end-point of the superradiant instability of electrically-charged Reissner-Nordstrom black holes in a cavity; we outline ways to explore this hypothesis.
Primordial massive gravitational waves from Einstein-Chern-Simons-Weyl gravity
Myung, Yun Soo; Moon, Taeyoon E-mail: tymoon@inje.ac.kr
2014-08-01
We investigate the evolution of cosmological perturbations during de Sitter inflation in the Einstein-Chern-Simons-Weyl gravity. Primordial massive gravitational waves are composed of one scalar, two vector and four tensor circularly polarized modes. We show that the vector power spectrum decays quickly like a transversely massive vector in the superhorizon limit z ? 0. In this limit, the power spectrum coming from massive tensor modes decays quickly, leading to the conventional tensor power spectrum. Also, we find that in the limit of m{sup 2} ? 0 (keeping the Weyl-squared term only), the vector and tensor power spectra disappear. It implies that their power spectra are not gravitationally produced because they (vector and tensor) are decoupled from the expanding de Sitter background, as a result of conformal invariance.
Thermodynamics of black holes in (n+1)-dimensional Einstein-Born-Infeld-dilaton gravity
Sheykhi, A.; Riazi, N.
2007-01-15
We construct a new class of (n+1)-dimensional (n{>=}3) black hole solutions in Einstein-Born-Infeld-dilaton gravity with Liouville-type potential for the dilaton field and investigate their properties. These solutions are neither asymptotically flat nor (anti)-de Sitter. We find that these solutions can represent black holes, with inner and outer event horizons, an extreme black hole, or a naked singularity provided the parameters of the solutions are chosen suitably. We compute the thermodynamic quantities of the black hole solutions and find that these quantities satisfy the first law of thermodynamics. We also perform a stability analysis and investigate the effect of dilaton on the stability of the solutions.
Radiating black holes in Einstein-Yang-Mills theory and cosmic censorship
Ghosh, Sushant G.; Dadhich, Naresh
2010-08-15
Exact nonstatic spherically symmetric black-hole solutions of the higher dimensional Einstein-Yang-Mills equations for a null dust with Yang-Mills gauge charge are obtained by employing Wu-Yang ansatz, namely, HD-EYM Vaidya solution. It is interesting to note that gravitational contribution of Yang-Mills (YM) gauge charge for this ansatz is indeed opposite (attractive rather than repulsive) that of Maxwell charge. It turns out that the gravitational collapse of null dust with YM gauge charge admits strong curvature shell focusing naked singularities violating cosmic censorship. However, there is significant shrinkage of the initial data space for a naked singularity of the HD-Vaidya collapse due to presence of YM gauge charge. The effect of YM gauge charge on structure and location of the apparent and event horizons is also discussed.
Dark energy as a fixed point of the Einstein Yang-Mills Higgs Equations
Rinaldi, Massimiliano
2015-01-01
We study the Einstein Yang-Mills Higgs equations in the $SO(3)$ representation on a isotropic and homogeneous flat Universe, in the presence of radiation and matter fluids. We map the equations of motion into a closed dynamical system of first-order differential equations and we find the equilibrium points. We show that there is only one stable fixed point that corresponds to an accelerated expanding Universe in the future. In the past, instead, there is an unstable fixed point that implies a stiff-matter domination. In between, we find three other unstable fixed points, corresponding, in chronological order, to radiation domination, to matter domination, and, finally, to a transition from decelerated expansion to accelerated expansion. We solve the system numerically and we confirm that there are smooth trajectories that correctly describe the evolution of the Universe, from a remote past dominated by radiation to a remote future dominated by dark energy, passing through a matter-dominated phase.
Dark energy as a fixed point of the Einstein Yang-Mills Higgs Equations
Massimiliano Rinaldi
2015-09-02
We study the Einstein Yang-Mills Higgs equations in the $SO(3)$ representation on a isotropic and homogeneous flat Universe, in the presence of radiation and matter fluids. We map the equations of motion into an autonomous dynamical system of first-order differential equations and we find the equilibrium points. We show that there is only one stable fixed point that corresponds to an accelerated expanding Universe in the future. In the past, instead, there is an unstable fixed point that implies a stiff-matter domination. In between, we find three other unstable fixed points, corresponding, in chronological order, to radiation domination, to matter domination, and, finally, to a transition from decelerated expansion to accelerated expansion. We solve the system numerically and we confirm that there are smooth trajectories that correctly describe the evolution of the Universe, from a remote past dominated by radiation to a remote future dominated by dark energy, passing through a matter-dominated phase.
Radiation to atom quantum mapping by collective recoil in Bose-Einstein condensate
Matteo G. A. Paris; Mary Cola; Nicola Piovella; Rodolfo Bonifacio
2003-02-20
We propose an experiment to realize radiation to atom continuous variable quantum mapping, i.e. to teleport the quantum state of a single mode radiation field onto the collective state of atoms with a given momentum out of a Bose-Einstein condensate. The atoms-radiation entanglement needed for the teleportation protocol is established through the interaction of a single mode with the condensate in presence of a strong far off-resonant pump laser, whereas the coherent atomic displacement is obtained by the same interaction with the radiation in a classical coherent field. In principle, verification of the protocol requires a joint measurement on the recoiling atoms and the condensate, however, a partial verification involving populations, i.e. diagonal matrix elements may be obtained through counting atoms experiments.
Relativistic Gross-Pitaevskii equation and the cosmological Bose Einstein Condensation
Takeshi Fukuyama; Masahiro Morikawa
2006-01-30
We do not know 96% of the total matter in the universe at present. In this paper, a cosmological model is proposed in which Dark Energy (DE) is identified as Bose-Einstein Condensation (BEC) of some boson field. Global cosmic acceleration caused by this BEC and multiple rapid collapses of BEC into black holes etc. (=Dark Matter (DM)) are examined based on the relativistic version of the Gross-Pitaevskii equation. We propose (a) a novel mechanism of inflation free from the slow-rolling condition, (b) a natural solution for the cosmic coincidence ('Why Now?') problem through the transition from DE into DM, (c) very early formation of highly non-linear objects such as black holes, which might trigger the first light as a form of quasars, and (d) log-z periodicity in the subsequent BEC collapsing time. All of these are based on the steady slow BEC process.
De finetti theorems, mean-field limits and bose-Einstein condensation
Nicolas Rougerie
2015-06-17
These notes deal with the mean-field approximation for equilibrium states of N-body systems in classical and quantum statistical mechanics. A general strategy for the justification of effective models based on statistical independence assumptions is presented in details. The main tools are structure theorems {\\`a} la de Finetti, describing the large N limits of admissible states for these systems. These rely on the symmetry under exchange of particles, due to their indiscernability. Emphasis is put on quantum aspects, in particular the mean-field approximation for the ground states of large bosonic systems, in relation with the Bose-Einstein condensation phenomenon. Topics covered in details include: the structure of reduced density matrices for large bosonic systems, Fock-space localization methods, derivation of effective energy functionals of Hartree or non-linear Schr{\\"o}dinger type, starting from the many-body Schr{\\"o}dinger Hamiltonian.
Théorèmes de de Finetti, limites de champ moyen et condensation de Bose-Einstein
Nicolas Rougerie
2015-02-13
These lecture notes treat the mean-field approximation for equilibrium states of N body systems in classical and quantum statistical mechanics. A general strategy to justify effective models based on assumptions of statistical independence of the particles is in presented in detail. The main tools are a structure theorems of de Finetti that describe large N limits of states accessible to the systems in question, exploiting the indistinguishablity of particles. The focus is on quantum aspects, particularly the mean-field approximation for the ground state of a large system of bosons, in connection with Bose-Einstein condensation: structure of reduced density matrices of a large bosonic system, localization methods in Fock space, derivation of Hartree and non-linear Schr\\"odinger effective energy functionals.
Radio-frequency induced ground state degeneracy in a Chromium Bose-Einstein condensate
Q. Beaufils; T. Zanon; R. Chicireanu; B. Laburthe-Tolra; E. Marechal; L. Vernac; J. -C. Keller; O. Gorceix
2008-09-29
We study the effect of strong radio-frequency (rf) fields on a chromium Bose-Einstein condensate (BEC), in a regime where the rf frequency is much larger than the Larmor frequency. We use the modification of the Land\\'{e} factor by the rf field to bring all Zeeman states to degeneracy, despite the presence of a static magnetic field of up to 100 mG. This is demonstrated by analyzing the trajectories of the atoms under the influence of dressed magnetic potentials in the strong field regime. We investigate the problem of adiabaticity of the rf dressing process, and relate it to how close the dressed states are to degeneracy. Finally, we measure the lifetime of the rf dressed BECs, and identify a new rf-assisted two-body loss process induced by dipole-dipole interactions.
Superfluid Dynamics of a Bose-Einstein Condensate in a Periodic Potential
C. Menotti; A. Smerzi; A. Trombettoni
2003-10-31
We investigate the superfluid properties of a Bose-Einstein condensate (BEC) trapped in a one dimensional periodic potential. We study, both analytically (in the tight binding limit) and numerically, the Bloch chemical potential, the Bloch energy and the Bogoliubov dispersion relation, and we introduce {\\it two} different, density dependent, effective masses and group velocities. The Bogoliubov spectrum predicts the existence of sound waves, and the arising of energetic and dynamical instabilities at critical values of the BEC quasi-momentum which dramatically affect its coherence properties. We investigate the dependence of the dipole and Bloch oscillation frequencies in terms of an effective mass averaged over the density of the condensate. We illustrate our results with several animations obtained solving numerically the time-dependent Gross-Pitaevskii equation.
Long-lived periodic revivals of coherence in an interacting Bose-Einstein condensate
Egorov, M.; Ivannikov, V.; Opanchuk, B.; Drummond, P.; Hall, B. V.; Sidorov, A. I. [ARC Centre of Excellence for Quantum-Atom Optics and Centre for Atom Optics and Ultrafast Spectroscopy, Swinburne University of Technology, Melbourne 3122 (Australia); Anderson, R. P. [ARC Centre of Excellence for Quantum-Atom Optics and Centre for Atom Optics and Ultrafast Spectroscopy, Swinburne University of Technology, Melbourne 3122 (Australia); School of Physics, Monash University, Victoria 3800 (Australia)
2011-08-15
We observe the coherence of an interacting two-component Bose-Einstein condensate (BEC) surviving for seconds in a trapped Ramsey interferometer. Mean-field-driven collective oscillations of two components lead to periodic dephasing and rephasing of condensate wave functions with a slow decay of the interference fringe visibility. We apply spin echo synchronous with the self-rephasing of the condensate to reduce the influence of state-dependent atom losses, significantly enhancing the visibility up to 0.75 at the evolution time of 1.5 s. Mean-field theory consistently predicts higher visibility than experimentally observed values. We quantify the effects of classical and quantum noise and infer a coherence time of 2.8 s for a trapped condensate of 5.5x10{sup 4} interacting atoms.
Bose-Einstein condensates on tilted lattices: Coherent, chaotic, and subdiffusive dynamics
Kolovsky, Andrey R.; Gomez, Edgar A.; Korsch, Hans Juergen
2010-02-15
The dynamics of a (quasi-) one-dimensional interacting atomic Bose-Einstein condensate in a tilted optical lattice is studied in a discrete mean-field approximation, i.e., in terms of the discrete nonlinear Schroedinger equation. If the static field is varied, the system shows a plethora of dynamical phenomena. In the strong field limit, we demonstrate the existence of (almost) nonspreading states which remain localized on the lattice region populated initially and show coherent Bloch oscillations with fractional revivals in the momentum space (so-called quantum carpets). With decreasing field, the dynamics becomes irregular, however, still confined in configuration space. For even weaker fields, we find subdiffusive dynamics with a wave-packet width growing as t{sup 1/4}.
The Music of the Aetherwave - B-mode Polarization in Einstein-Aether Theory
Masahiro Nakashima; Tsutomu Kobayashi
2011-03-11
We study how the dynamical vector degree of freedom in modified gravity affects the CMB B-mode polarization in terms of the Einstein-aether theory. In this theory, vector perturbations can be generated from inflation, which can grow on superhorizon scales in the subsequent epochs and thereby leaves imprints on the CMB B-mode polarization. We derive the linear perturbation equations in a covariant formalism, and compute the CMB B-mode polarization using the CAMB code modified so as to incorporate the effect of the aether vector field. We find that the amplitude of the B-mode signal from the aether field can surpass the contribution from the inflationary gravitational waves for a viable range of model parameters. We also give an analytic argument explaining the shape of the spectrum based on the tight coupling approximation.
Cosmological reconstruction and {\\it Om} diagnostic analysis of Einstein-Aether Theory
Pasqua, Antonio; Momeni, Davood; Raza, Muhammad; Myrzakulov, Ratbay
2015-01-01
Cosmological reconstruction technique is applied to study the cosmology of the Einstein-Aether (EA) gravity. We reconstructed an analytical model of EA theory for a type of Hubble dependent dark energy density proposed by Granda and Oliveros. The reconstructed cosmological scale factors are comprised of power-law, future singular model, emergent scale factor, intermediate scale factor, a unified theory for matter and dark energy dominated phases and finally for a type of non-extensive exponential scale factor, the q-de Sitter scale factor. In each cosmological epoch, we reconstruct the Lagrangian of the vector part of theory $F(K)$. Furthermore, \\emph{Om} diagnostic analysis technique is applied to fit parameters using recent observational data, namely Type Ia Supernovae, BAO, and data of Hubble parameter.
On the Third Critical Speed for Rotating Bose-Einstein Condensates
M. Correggi; D. Dimonte
2015-08-28
We study a two-dimensional rotating Bose-Einstein condensate confined by an anharmonic trap in the framework of the Gross-Pitaevksii theory. We consider a rapid rotation regime close to the transition to a giant vortex state. It was proven in [M. Correggi {\\it et al}, {\\it J. Math. Phys. \\textbf{53}(2012)] that such a transition occurs when the angular velocity is of order $ \\varepsilon ^{-4}$, with $ \\varepsilon ^{-2} $ denoting the coefficient of the nonlinear term in the Gross-Pitaevskii functional and $ \\varepsilon \\ll 1 $ (Thomas-Fermi regime). In this paper we identify a finite value $ \\Omega_{\\mathrm{c}} $ such that, if $ \\Omega = \\Omega_0/\\varepsilon ^4 $ with $ \\Omega_0 > \\Omega_{\\mathrm{c}} $, the condensate is in the giant vortex phase. Under the same condition we prove a refined energy asymptotics and an estimate of the winding number of any Gross-Pitaevskii minimizer.
On the Third Critical Speed for Rotating Bose-Einstein Condensates
M. Correggi; D. Dimonte
2016-01-07
We study a two-dimensional rotating Bose-Einstein condensate confined by an anharmonic trap in the framework of the Gross-Pitaevksii theory. We consider a rapid rotation regime close to the transition to a giant vortex state. It was proven in [M. Correggi {\\it et al}, {\\it J. Math. Phys. \\textbf{53}(2012)] that such a transition occurs when the angular velocity is of order $ \\varepsilon ^{-4}$, with $ \\varepsilon ^{-2} $ denoting the coefficient of the nonlinear term in the Gross-Pitaevskii functional and $ \\varepsilon \\ll 1 $ (Thomas-Fermi regime). In this paper we identify a finite value $ \\Omega_{\\mathrm{c}} $ such that, if $ \\Omega = \\Omega_0/\\varepsilon ^4 $ with $ \\Omega_0 > \\Omega_{\\mathrm{c}} $, the condensate is in the giant vortex phase. Under the same condition we prove a refined energy asymptotics and an estimate of the winding number of any Gross-Pitaevskii minimizer.
Domain Wall Model in the Galactic Bose-Einstein Condensate Halo
J. C. C. de Souza; M. O. C. Pires
2013-05-22
We assume that the galactical dark matter halo, considered composed of an axionlike particles Bose-Einstein condensate \\cite{pir12}, can present topological defects, namely domain walls, arising as the dark soliton solution for the Gross-Pitaevskii equation in a self-graviting potential. We investigate the influence that such substructures would have in the gravitational interactions within a galaxy. We find that, for the simple domain wall model proposed, the effects are too small to be identified, either by means of a local measurement of the gradient of the gravitational field or by analysing galaxy rotation curves. In the first case, the gradient of the gravitational field in the vicinity of the domain wall would be $10^{-31}\\; (m/s^2)/m$. In the second case, the ratio of the tangential velocity correction of a star due to the presence of the domain wall to the velocity in the spherical symmetric case would be $10^{-8}$.
Dissipation induced coherence and stochastic resonance of an open two-mode Bose-Einstein condensate
D. Witthaut; F. Trimborn; S. Wimberger
2009-02-03
We discuss the dynamics of a Bose-Einstein condensate in a double-well trap subject to phase noise and particle loss. The phase coherence of a weakly-interacting condensate, experimentally measured via the contrast in an interference experiment, as well as the response to an external driving become maximal for a finite value of the dissipation rate matching the intrinsic time scales of the system. This can be understood as a stochastic resonance of the many-particle system. Even stronger effects are observed when dissipation acts in concurrence with strong inter-particle interactions, restoring the purity of the condensate almost completely and increasing the phase coherence significantly. Our theoretical results are backed by Monte Carlo simulations, which show a good qualitative agreement and provide a microscopic explanation for the observed stochastic resonance effect.
Analogue quantum gravity phenomenology from a two-component Bose-Einstein condensate
Stefano Liberati; Matt Visser; Silke Weinfurtner
2006-03-16
We present an analogue spacetime model that reproduces the salient features of the most common ansatz for quantum gravity phenomenology. We do this by investigating a system of two coupled Bose-Einstein condensates. This system can be tuned to have two "phonon" modes (one massive, one massless) which share the same limiting speed in the hydrodynamic approximation [Phys. Rev. D72 (2005) 044020, gr-qc/0506029; cond-mat/0409639]. The system nevertheless possesses (possibly non-universal) Lorentz violating terms at very high energies where "quantum pressure" becomes important. We investigate the physical interpretation of the relevant fine-tuning conditions, and discuss the possible lessons and hints that this analogue spacetime could provide for the phenomenology of real physical quantum gravity. In particular we show that the effective field theory of quasi-particles in such an emergent spacetime does not exhibit the so called "naturalness problem".
Characteristic Size and Mass of Galaxies in the Bose-Einstein Condensate Dark Matter Model
Lee, Jae-Weon
2015-01-01
We study an inherent length scale of galactic halos in the Bose-Einstein condensate (or scalar field) dark matter model. Considering evolution of the density perturbation we show that the average background matter density determines a quantum Jeans mass and hence the spatial size of galaxies. In this model the minimum size of galaxies increases, while the minimum mass of the galaxies decreases as the universe evolves. The observed values of the mass and the size of the dwarf galaxies are successfully reproduced with the dark matter particle mass $m\\simeq 5\\times 10^{-22}eV$. The rotation velocity of dwarf galaxies is $O(\\sqrt{H/m}$) c, where $H$ is the Hubble parameter. We also suggest that ultra compact dwarf galaxies are remnants of dwarf galaxies formed in the early universe.
Chaotic behavior of three interacting vortices in a confined Bose-Einstein condensate
Kyriakopoulos, Nikos; Koukouloyannis, Vassilis; Skokos, Charalampos; Kevrekidis, Panayotis G.
2014-06-01
Motivated by recent experimental works, we investigate a system of vortex dynamics in an atomic Bose-Einstein condensate (BEC), consisting of three vortices, two of which have the same charge. These vortices are modeled as a system of point particles which possesses a Hamiltonian structure. This tripole system constitutes a prototypical model of vortices in BECs exhibiting chaos. By using the angular momentum integral of motion, we reduce the study of the system to the investigation of a two degree of freedom Hamiltonian model and acquire quantitative results about its chaotic behavior. Our investigation tool is the construction of scan maps by using the Smaller ALignment Index as a chaos indicator. Applying this approach to a large number of initial conditions, we manage to accurately and efficiently measure the extent of chaos in the model and its dependence on physically important parameters like the energy and the angular momentum of the system.
Feshbach-resonant Raman photoassociation in a Bose-Einstein condensate
Mackie, Matt; Phou, Pierre; Shinn, Mannix; Boyce, Heather; Katz, Lev
2011-10-15
We model the formation of stable heteronuclear molecules via pulsed Raman photoassociation of a two-component Bose-Einstein condensate near a strong Feshbach resonance, for both counterintuitive and intuitive pulse sequencing. Compared to lasers alone, weak Raman photoassociation is enhanced by as much as a factor of ten (five) for a counterintuitive (intuitive) pulse sequence, whereas strong Raman photoassociation is barely enhanced at all--regardless of pulse sequence. Stronger intra-atom, molecule, or atom-molecule collisions lead to an expected decrease in conversion efficiency, but stronger ambient inter-atom collisions lead to an unexpected increase in the efficiency of stable molecule production. Numerical results agree reasonably with an analytical approximation.
Novel Bose-Einstein Interference in the Passage of a Fast Particle in a Dense Medium
Cheuk-Yin Wong
2012-03-20
When an energetic particle collides coherently with many medium particles at high energies, the Bose-Einstein symmetry with respect to the interchange of the exchanged virtual bosons leads to a destructive interference of the Feynman amplitudes in most regions of the phase space but a constructive interference in some other regions of the phase space. As a consequence, the recoiling medium particles have a tendency to come out collectively along the direction of the incident fast particle, each carrying a substantial fraction of the incident longitudinal momentum. Such an interference appearing as collective recoils of scatterers along the incident particle direction may have been observed in angular correlations of hadrons associated with a high-$p_T$ trigger in high-energy AuAu collisions at RHIC.
Anderson Localization of Bogolyubov Quasiparticles in Interacting Bose-Einstein Condensates
Lugan, P.; Clement, D.; Bouyer, P.; Aspect, A.; Sanchez-Palencia, L. [Laboratoire Charles Fabry de l'Institut d'Optique, CNRS and Univ. Paris-Sud, Campus Polytechnique, RD 128, F-91127 Palaiseau cedex (France)
2007-11-02
We study the Anderson localization of Bogolyubov quasiparticles in an interacting Bose-Einstein condensate (with a leading length {xi}) subjected to a random potential (with a finite correlation length {sigma}{sub R}). We derive analytically the Lyapunov exponent as a function of the quasiparticle momentum k, and we study the localization maximum k{sub max}. For 1D speckle potentials, we find that k{sub max}{proportional_to}1/{xi} when {xi}>>{sigma}{sub R} while k{sub max}{proportional_to}1/{sigma}{sub R} when {xi}<<{sigma}{sub R}, and that the localization is strongest when {xi}{approx}{sigma}{sub R}. Numerical calculations support our analysis, and our estimates indicate that the localization of the Bogolyubov quasiparticles is accessible in experiments with ultracold atoms.
New black holes of vacuum Einstein equations with hyperscaling violation and Nil geometry horizons
Mokhtar Hassaine
2015-03-05
In this paper, we present a new solution of the vacuum Einstein equations in five dimensions which is a static black hole with hyperscaling violation and with a three-dimensional horizon modeled by one the eight Thurston geometries, namely the Nil geometry. This homogeneous geometry is non-trivial in the sense that it is neither of constant curvature nor a product of constant curvature manifolds. Using the Hamiltonian formalism, we identify the mass and entropy of the black hole solution. Curiously enough, in spite of the fact that the entropy turns to be negative, the mass is positive and the first law of thermodynamics holds. We also discuss the extension in higher dimension.
Bose-Einstein condensation of triplons in Ba3Cr2O8
Jaime, Marcelo [Los Alamos National Laboratory; Kohama, Y [Los Alamos National Laboratory; Aczel, A [MCMASTER UNIV; Ninios, K [UNIV OF FL; Chan, H [UNIV OF FL; Balicas, L [NHMFL; Dabkowska, H [MCMASTER UNIV; Like, G [MCMASTER UNIV
2009-01-01
By performing heat capacity, magnetocaloric effect, torque magnetometry and force magnetometry measurements up to 33 T, we have mapped out the T-H phase diagram of the S = 1/2 spin dimer compound Ba{sub 3}Cr{sub 2}O{sub 8}. We found evidence for field-induced magnetic order between H{sub cl} = 12.52(2) T and H{sub c2} = 23.65(5) T, with the maximum transition temperature T{sub c} {approx} 2.7 K at H {approx} 18 T. The lower transition can likely be described by Bose-Einstein condensation of triplons theory, and this is consistent with the absence of any magnetization plateaus in our magnetic torque and force measurements. In contrast, the nature of the upper phase transition appears to be quite different as our measurements suggest that this transition is actually first order.
James Bock; Asantha Cooray; Shaul Hanany; Brian Keating; Adrian Lee; Tomotake Matsumura; Michael Milligan; Nicolas Ponthieu; Tom Renbarger; Huan Tran
2008-05-27
This is the Phase 1 Report on the Experimental Probe of Inflationary Cosmology (EPIC), a mission concept study for NASA's Einstein Inflation Probe. When we began our study we sought to answer five fundamental implementation questions: 1) can foregrounds be measured and subtracted to a sufficiently low level?; 2) can systematic errors be controlled?; 3) can we develop optics with sufficiently large throughput, low polarization, and frequency coverage from 30 to 300 GHz?; 4) is there a technical path to realizing the sensitivity and systematic error requirements?; and 5) what are the specific mission architecture parameters, including cost? Detailed answers to these questions are contained in this report. Currently in Phase 2, we are exploring a mission concept targeting a ~2m aperture, in between the two options described in the current report with a small (~30 cm) and large (~4m) missions.
Carlos Barcelo; Stefano Liberati; Matt Visser
2003-08-14
Bose-Einstein condensates (BEC) have recently been the subject of considerable study as possible analogue models of general relativity. In particular it was shown that the propagation of phase perturbations in a BEC can, under certain conditions, closely mimic the dynamics of scalar quantum fields in curved spacetimes. In two previous articles [gr-qc/0110036, gr-qc/0305061] we noted that a varying scattering length in the BEC corresponds to a varying speed of light in the ``effective metric''. Recent experiments have indeed achieved a controlled tuning of the scattering length in Rubidium 85. In this article we shall discuss the prospects for the use of this particular experimental effect to test some of the predictions of semiclassical quantum gravity, for instance, particle production in an expanding universe. We stress that these effects are generally much larger than the Hawking radiation expected from causal horizons, and so there are much better chances for their detection in the near future.
Einstein–Cartan gravity, Asymptotic Safety, and the running Immirzi parameter
Daum, J.-E.; Reuter, M.
2013-07-15
In this paper we analyze the functional renormalization group flow of quantum gravity on the Einstein–Cartan theory space. The latter consists of all action functionals depending on the spin connection and the vielbein field (co-frame) which are invariant under both spacetime diffeomorphisms and local frame rotations. In the first part of the paper we develop a general methodology and corresponding calculational tools which can be used to analyze the flow equation for the pertinent effective average action for any truncation of this theory space. In the second part we apply it to a specific three-dimensional truncated theory space which is parametrized by Newton’s constant, the cosmological constant, and the Immirzi parameter. A comprehensive analysis of their scale dependences is performed, and the possibility of defining an asymptotically safe theory on this hitherto unexplored theory space is investigated. In principle Asymptotic Safety of metric gravity (at least at the level of the effective average action) is neither necessary nor sufficient for Asymptotic Safety on the Einstein–Cartan theory space which might accommodate different “universality classes” of microscopic quantum gravity theories. Nevertheless, we do find evidence for the existence of at least one non-Gaussian renormalization group fixed point which seems suitable for the Asymptotic Safety construction in a setting where the spin connection and the vielbein are the fundamental field variables. -- Highlights: •A functional RG equation for a first order formulation of gravity is constructed. •The theory space constituted by tetrad and spin connection variables is explored. •The RG equation is solved in a 3 dimensional truncation of theory space. •The flow of Newton’s constant, the cosmological constant and the Immirzi parameter is analyzed. •Evidence for the nonperturbative renormalizability of the theory is found.
EMPIRICAL DETERMINATION OF EINSTEIN A-COEFFICIENT RATIOS OF BRIGHT [Fe II] LINES
Giannini, T.; Antoniucci, S.; Nisini, B.; Lorenzetti, D.; Alcalá, J. M.; Bacciotti, F.; Podio, L.; Bonito, R.; Stelzer, B.
2015-01-01
The Einstein spontaneous rates (A-coefficients) of Fe{sup +} lines have been computed by several authors with results that differ from each other by up to 40%. Consequently, models for line emissivities suffer from uncertainties that in turn affect the determination of the physical conditions at the base of line excitation. We provide an empirical determination of the A-coefficient ratios of bright [Fe II] lines that would represent both a valid benchmark for theoretical computations and a reference for the physical interpretation of the observed lines. With the ESO-Very Large Telescope X-shooter instrument between 3000 Å and 24700 Å, we obtained a spectrum of the bright Herbig-Haro object HH 1. We detect around 100 [Fe II] lines, some of which with a signal-to-noise ratios ?100. Among these latter lines, we selected those emitted by the same level, whose dereddened intensity ratios are direct functions of the Einstein A-coefficient ratios. From the same X-shooter spectrum, we got an accurate estimate of the extinction toward HH 1 through intensity ratios of atomic species, H I recombination lines and H{sub 2} ro-vibrational transitions. We provide seven reliable A-coefficient ratios between bright [Fe II] lines, which are compared with the literature determinations. In particular, the A-coefficient ratios involving the brightest near-infrared lines (?12570/?16440 and ?13209/?16440) are in better agreement with the predictions by the Quinet et al. relativistic Hartree-Fock model. However, none of the theoretical models predict A-coefficient ratios in agreement with all of our determinations. We also show that literature data of near-infrared intensity ratios better agree with our determinations than with theoretical expectations.
502 NATURE PHOTONICS | VOL 4 | AUGUST 2010 | www.nature.com/naturephotonics news & views
Fischer, Baruch
, Albert Einstein extended the mathematics of the Indian physicist Satyendra Nath Bose to cover an ensemble of non-interacting atoms. In doing so he created what is now famously known as BoseEinstein statistics century: the phenomenon known as BoseEinstein condensation2 . Experimental demonstration was initially
Victor M. Bogdan
2009-10-17
NASA's Jet Propulsion Laboratory put on You Tube a problem that has been baffling the scientists for sometime. It involves an unexpected force acting on the space probes. The author proves that NASA'S satellite orbit anomaly problem can be solved in the frame of Einstein's Special Theory of Relativity. The anomaly confirms that gravity fields propagate with velocity of light as Einstein predicted. The proof is based on the authors discovery of the relativistic version of Newton's gravity field. The author provides formulas for relativistic equation of motion for a spacecraft in the joint gravitational field of the Earth and the Sun in a Lorentzian frame attached to the Earth. The formulas are suitable for digital computers and can be easily implemented. He also shows how to find solutions of the relativistic equations of motion for the spacecraft.
Baker, Erin Shammel; Muddiman, David C.; Loo, Joseph
2014-12-01
This special focus issue of the Journal of the American Society for Mass Spectrometry celebrates the accomplishments of Dr. Richard D. Smith, the recipient of the 2013ASMS Award for a Distinguished Contribution in Mass Spectrometry, and who serves as a Battelle Fellow, Chief Scientist in the Biological Sciences Division, and Director of Proteomics Research at Pacific Northwest National Laboratory (PNNL) in Richland, WA. The award is for his development of the electrodynamic ion funnel.
Kato, Chinami; Yamada, Shoichi; Takahashi, Koh; Umeda, Hideyuki; Yoshida, Takashi; Ishidoshiro, Koji
2015-01-01
Aiming to distinguish two types of progenitors of core collapse supernovae, i.e., one with a core composed mainly of oxygen and neon (abbreviated as ONe core) and the other with an iron core (or Fe core), we calculated the luminosities and spectra of neutrinos emitted from these cores prior to gravitational collapse, taking neutrino oscillation into account. We found that the total energies emitted as $\\bar{\
Using Relative Costs in Workflow Scheduling to Cope with Input Data Uncertainty
Sakellariou, Rizos
Institute of Computing University of Campinas Av. Albert Einstein, 1251 Campinas, São Paulo, Brazil bit, UK rizos@cs.man.ac.uk Edmundo R. M. Madeira Institute of Computing University of Campinas Av. Albert information about duration of tasks and communication between tasks in the workflow. However, such information
Becker, Ulrich J.
Bose–Einstein correlations of pairs of identical charged pions produced in hadronic Z decays are analyzed in terms of various parametrizations. A good description is achieved using a Lévy stable distribution in conjunction ...
Bernhard Rothenstein
2005-06-20
We show that the transformation equations for the parameters that characterize a plane acoustic wave: period, (frequency), wave vector, wave length and phase velocity can be derived without using phase invariance and Lorentz-Einstein transformation
Canales, Jimena
Loving Faster Than Light: Romance and Readers in Einstein's Universe by K. Price, University in Love. But Katy Price is after a deeper connec- tion in Loving Faster Than Light. The cover modestly
Oshmyansky, A
2007-01-01
An alternative quantum field theory for gravity is proposed for low energies based on an attractive effect between contaminants in a Bose-Einstein Condensate rather than on particle exchange. In the ``contaminant in condensate effect," contaminants cause a potential in an otherwise uniform condensate, forcing the condensate between two contaminants to a higher energy state. The energy of the system decreases as the contaminants come closer together, causing an attractive force between contaminants. It is proposed that mass-energy may have a similar effect on Einstein's space-time field, and gravity is quantized by the same method by which the contaminant in condensate effect is quantized. The resulting theory is finite and, if a physical condensate is assumed to underly the system, predictive. However, the proposed theory has several flaws at high energies and is thus limited to low energies. Falsifiable predictions are given for the case that the Higgs condensate is assumed to be the condensate underlying gr...
Marek Rogatko
1998-07-09
Using the ADM formulation of the Einstein-Maxwell axion-dilaton gravity we derived the formulas for the variation of mass and other asymptotic conserved quantities in the theory under consideration. Generalizing this kind of reasoning to the initial dota for the manifold with an interior boundary we got the generalized first law of black hole mechanics. We consider an asymptotically flat solution to the Einstein-Maxwell axion-dilaton gravity describing a black hole with a Killing vector field timelike at infinity, the horizon of which comprises a bifurcate Killing horizon with a bifurcate surface. Supposing that the Killing vector field is asymptotically orthogonal to the static hypersurface with boundary S and compact interior, we find that the solution is static in the exterior world, when the timelike vector field is normal to the horizon and has vanishing electric and axion- electric fields on static slices.
Z. Haghshenasfard; M. H. Naderi; M. Soltanolkotabi
2008-07-11
In this paper, we investigate the spectrum of light scattered from a Bose-Einstein condensate in the framework of f-deformed boson. We use an f-deformed quantum model in which the Gardiners phonon operators for BEC are deformed by an operator-valued function, f(n), of the particle-number operator n. We consider the collisions between the atoms as a special kind of f-deformation. The collision rate k is regarded as the deformation parameter and the spectrum of light scattered from the deformed BEC is analyzed. In particular, we find that with increasing the values of deformation parameters k and eta=1/N (N, total number of condensate atoms) the scattering spectrum shows deviation from the spectrum associated with nondeformed Bose-Einstein condensate.
Alexander Oshmyansky
2007-03-08
An alternative quantum field theory for gravity is proposed for low energies based on an attractive effect between contaminants in a Bose-Einstein Condensate rather than on particle exchange. In the ``contaminant in condensate effect," contaminants cause a potential in an otherwise uniform condensate, forcing the condensate between two contaminants to a higher energy state. The energy of the system decreases as the contaminants come closer together, causing an attractive force between contaminants. It is proposed that mass-energy may have a similar effect on Einstein's space-time field, and gravity is quantized by the same method by which the contaminant in condensate effect is quantized. The resulting theory is finite and, if a physical condensate is assumed to underly the system, predictive. However, the proposed theory has several flaws at high energies and is thus limited to low energies. Falsifiable predictions are given for the case that the Higgs condensate is assumed to be the condensate underlying gravity.
Fang-Pei Chen
2007-03-10
Based on investigations of the fundamental properties of the generalized Einstein Lagrangian density for a gravitational system, the theoretical foundations of the modified Einstein field equations and the Lorentz and Levi-Civita conservation laws are systematically studied. The theory of cosmology developed on the basis of these equations and laws is analyzed in detail. Some new properties and new effects of the cosmos are deduced; these new properties and new effects could be tested via future experiments and observations.
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
evening to honor Albert Einstein's scientific achievements and his love of violin music. On Saturday, April 30, at 8 p.m., British violinist Jack Liebeck will appear in...
The Bedford Bulletin January 9, 2003 http://www.yourneighborhoodnews.com/bullarc010903.html
Riabov, Vladimir V.
writes, "Strong winds blow down beautiful leaves from trees in autumn. I have decided to pick them up of Albert Einstein sticking his tongue out. Riabov holds a tall glass of beer and another glass is under
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
carpenters use lasers to construct level buildings, while homeowners use them to hang pictures. The origin of lasers can be traced to Albert Einstein, who rst theorized that it was...
Y-12 employees, families and friends help East Tennessee during...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Chris Clark helps ready the Discovery Lab at the Oak Ridge Children's Museum for a new paint job. Looking on is Clark's mustached compadre Albert Einstein. Karen Dixon, Chris...
Yutaka Hosotani; Hiroki Emoto; Takahiro Kubota
2002-09-11
In the SU(2)_L x U(1)_Y standard electroweak theory coupled with the Einstein gravity, new topological configurations naturally emerge, if the spatial section of the universe is globally a three-sphere (S^3) with a small radius. The SU(2)_L gauge fields wrap the space nontrivially, producing homogeneous but anisotropic space. As the universe expands, large electric and magnetic fields are produced. The electromagnetic field configuration is characterized by the Hopf map.
Cang, Nguyen The
2015-01-01
In this paper, we introduce new methods for solving the vacuum Einstein constraints equations: the first one is based on Schaefer's fixed point theorem (known methods use Schauder's fixed point theorem) while the second one uses the concept of half-continuity coupled with the introduction of local supersolutions. These methods allow to: unify some recent existence results, simplify many proofs (for instance, the main theorem in arXiv:1012.2188) and weaken the assumptions of many recent results.
Stephani, H.
1988-07-01
The framework of Lie--Baecklund (or generalized) symmetries is used to give a unifying view of some of the known symmetries of Einstein's field equations for the vacuum or perfect fluid case (with a ..mu.. = p or a ..mu..+3p = 0 equation of state). These symmetries occur if space-time admits one or two Killing vectors (orthogonal or parallel, respectively, to the four-velocity in the perfect fluid case).
Ujjal Debnath; Mubasher Jamil
2015-01-03
In this work, we focus on the collapse of a spherically symmetric perturbation, with a classical top-hat profile, to study the nonlinear evolution of only viscous modified Chaplygin gas (VMCG) perturbations in Einstein's gravity as well as in loop quantum Cosmology (LQC). In the perturbed region, we have investigated the natures of equation of state parameter, square speed of sound and another perturbed quantities. The results have been analyzed by numerical and graphical investigations.
Anatoly V. Latyshev; Alexander A. Yushkanov
2010-01-18
The linearized kinetic equation modelling behaviour of the degenerate quantum bose gas with the frequency of collisions depending on momentum of elementary excitations is constructed. The general case of dependence of the elementary excitations energy on momentum according to Bogolyubov formula is considered. The analytical solution of the half-space boundary problem on temperature jump on border of degenerate bose gas in the presence of a Bose - Einstein condensate is received. Expression for Kapitsa resistance is received.
HERMES Collaboration; A. Airapetian; N. Akopov; Z. Akopov; E. C. Aschenauer; W. Augustyniak; R. Avakian; A. Avetissian; E. Avetisyan; S. Belostotski; N. Bianchi; H. P. Blok; A. Borissov; V. Bryzgalov; J. Burns; M. Capiluppi; G. P. Capitani; E. Cisbani; G. Ciullo; M. Contalbrigo; P. F. Dalpiaz; W. Deconinck; R. De Leo; E. De Sanctis; M. Diefenthaler; P. Di Nezza; M. Düren; G. Elbakian; F. Ellinghaus; E. Etzelmüller; R. Fabbri; A. Fantoni; L. Felawka; S. Frullani; G. Gapienko; V. Gapienko; J. Garay García; F. Garibaldi; G. Gavrilov; V. Gharibyan; F. Giordano; S. Gliske; M. Hartig; D. Hasch; Y. Holler; I. Hristova; Y. Imazu; A. Ivanilov; H. E. Jackson; S. Joosten; R. Kaiser; G. Karyan; T. Keri; E. Kinney; A. Kisselev; V. Korotkov; V. Kozlov; P. Kravchenko; V. G. Krivokhijine; L. Lagamba; L. Lapikás; I. Lehmann; P. Lenisa; A. López Ruiz; W. Lorenzon; X. -G. Lu; B. -Q. Ma; D. Mahon; N. C. R. Makins; Y. Mao; B. Marianski; A. Martinez de la Ossa; H. Marukyan; Y. Miyachi; A. Movsisyan; M. Murray; A. Mussgiller; E. Nappi; Y. Naryshkin; A. Nass; M. Negodaev; W. -D. Nowak; L. L. Pappalardo; R. Perez-Benito; A. Petrosyan; P. E. Reimer; A. R. Reolon; C. Riedl; K. Rith; G. Rosner; A. Rostomyan; J. Rubin; D. Ryckbosch; Y. Salomatin; A. Schäfer; G. Schnell; B. Seitz; T. -A. Shibata; V. Shutov; M. Stahl; M. Stancari; M. Statera; J. J. M. Steijger; S. Taroian; A. Terkulov; R. Truty; A. Trzcinski; M. Tytgat; Y. Van Haarlem; C. Van Hulse; D. Veretennikov; V. Vikhrov; I. Vilardi; S. Wang; S. Yaschenko; Z. Ye; S. Yen; B. Zihlmann; P. Zupranski
2015-07-18
Bose-Einstein correlations of like-sign charged hadrons produced in deep-inelastic electron and positron scattering are studied in the HERMES experiment using nuclear targets of $^1$H, $^2$H, $^3$He, $^4$He, N, Ne, Kr, and Xe. A Gaussian approach is used to parametrize a two-particle correlation function determined from events with at least two charged hadrons of the same sign charge. This correlation function is compared to two different empirical distributions that do not include the Bose-Einstein correlations. One distribution is derived from unlike-sign hadron pairs, and the second is derived from mixing like-sign pairs from different events. The extraction procedure used simulations incorporating the experimental setup in order to correct the results for spectrometer acceptance effects, and was tested using the distribution of unlike-sign hadron pairs. Clear signals of Bose-Einstein correlations for all target nuclei without a significant variation with the nuclear target mass are found. Also, no evidence for a dependence on the invariant mass W of the photon-nucleon system is found when the results are compared to those of previous experiments.
Airapetian, A; Akopov, Z; Aschenauer, E C; Augustyniak, W; Avakian, R; Avetissian, A; Avetisyan, E; Belostotski, S; Bianchi, N; Blok, H P; Borissov, A; Bryzgalov, V; Burns, J; Capiluppi, M; Capitani, G P; Cisbani, E; Ciullo, G; Contalbrigo, M; Dalpiaz, P F; Deconinck, W; De Leo, R; De Sanctis, E; Diefenthaler, M; Di Nezza, P; Düren, M; Elbakian, G; Ellinghaus, F; Etzelmüller, E; Fabbri, R; Fantoni, A; Felawka, L; Frullani, S; Gapienko, G; Gapienko, V; García, J Garay; Garibaldi, F; Gavrilov, G; Gharibyan, V; Giordano, F; Gliske, S; Hartig, M; Hasch, D; Holler, Y; Hristova, I; Imazu, Y; Ivanilov, A; Jackson, H E; Joosten, S; Kaiser, R; Karyan, G; Keri, T; Kinney, E; Kisselev, A; Korotkov, V; Kozlov, V; Kravchenko, P; Krivokhijine, V G; Lagamba, L; Lapikás, L; Lehmann, I; Lenisa, P; Ruiz, A López; Lorenzon, W; Lu, X -G; Ma, B -Q; Mahon, D; Makins, N C R; Mao, Y; Marianski, B; de la Ossa, A Martinez; Marukyan, H; Miyachi, Y; Movsisyan, A; Murray, M; Mussgiller, A; Nappi, E; Naryshkin, Y; Nass, A; Negodaev, M; Nowak, W -D; Pappalardo, L L; Perez-Benito, R; Petrosyan, A; Reimer, P E; Reolon, A R; Riedl, C; Rith, K; Rosner, G; Rostomyan, A; Rubin, J; Ryckbosch, D; Salomatin, Y; Schäfer, A; Schnell, G; Seitz, B; Shibata, T -A; Shutov, V; Stahl, M; Stancari, M; Statera, M; Steijger, J J M; Taroian, S; Terkulov, A; Truty, R; Trzcinski, A; Tytgat, M; Van Haarlem, Y; Van Hulse, C; Veretennikov, D; Vikhrov, V; Vilardi, I; Wang, S; Yaschenko, S; Ye, Z; Yen, S; Zihlmann, B; Zupranski, P
2015-01-01
Bose-Einstein correlations of like-sign charged hadrons produced in deep-inelastic electron and positron scattering are studied in the HERMES experiment using nuclear targets of $^1$H, $^2$H, $^3$He, $^4$He, N, Ne, Kr, and Xe. A Gaussian approach is used to parametrize a two-particle correlation function determined from events with at least two charged hadrons of the same sign charge. This correlation function is compared to two different empirical distributions that do not include the Bose-Einstein correlations. One distribution is derived from unlike-sign hadron pairs, and the second is derived from mixing like-sign pairs from different events. The extraction procedure used simulations incorporating the experimental setup in order to correct the results for spectrometer acceptance effects, and was tested using the distribution of unlike-sign hadron pairs. Clear signals of Bose-Einstein correlations for all target nuclei without a significant variation with the nuclear target mass are found. Also, no evidenc...
Ground Tests of Einstein's Equivalence Principle: From Lab-based to 10-m Atomic Fountains
Schlippert, D; Richardson, L L; Nath, D; Heine, H; Meiners, C; Wodey, É; Billon, A; Hartwig, J; Schubert, C; Gaaloul, N; Ertmer, W; Rasel, E M
2015-01-01
To date, no framework combining quantum field theory and general relativity and hence unifying all four fundamental interactions, exists. Violations of the Einstein's equivalence principle (EEP), being the foundation of general relativity, may hold the key to a theory of quantum gravity. The universality of free fall (UFF), which is one of the three pillars of the EEP, has been extensively tested with classical bodies. Quantum tests of the UFF, e.g. by exploiting matter wave interferometry, allow for complementary sets of test masses, orders of magnitude larger test mass coherence lengths and investigation of spin-gravity coupling. We review our recent work towards highly sensitive matter wave tests of the UFF on ground. In this scope, the first quantum test of the UFF utilizing two different chemical elements, Rb-87 and K-39, yielding an E\\"otv\\"os ratio $\\eta_{\\,\\text{Rb,K}}=(0.3\\pm 5.4)\\times 10^{-7}$ has been performed. We assess systematic effects currently limiting the measurement at a level of parts in...
Tomas Andrade; William R. Kelly; Donald Marolf
2015-06-09
The gravitational Dirichlet problem -- in which the induced metric is fixed on boundaries at finite distance from the bulk -- is related to simple notions of UV cutoffs in gauge/gravity duality and appears in discussions relating the low-energy behavior of gravity to fluid dynamics. We study the Einstein-Maxwell version of this problem, in which the induced Maxwell potential on the wall is also fixed. For flat walls in otherwise-asymptotically-flat spacetimes, we identify a moduli space of Majumdar-Papapetrou-like static solutions parametrized by the location of an extreme black hole relative to the wall. Such solutions may be described as balancing gravitational repulsion from a negative-mass image-source against electrostatic attraction to an oppositely-signed image charge. Standard techniques for handling divergences yield a moduli space metric with an eigenvalue that becomes negative near the wall, indicating a region of negative kinetic energy and suggesting that the Hamiltonian may be unbounded below. One may also surround the black hole with an additional (roughly spherical) Dirichlet wall to impose a regulator whose physics is more clear. Negative kinetic energies remain, though new terms do appear in the moduli-space metric. The regulator-dependence indicates that the adiabatic approximation may be ill-defined for classical extreme black holes with Dirichlet walls.
R. O'Shaughnessy
2003-06-30
Many alternative formulations of Einstein's evolution have lately been examined, in an effort to discover one which yields slow growth of constraint-violating errors. In this paper, rather than directly search for well-behaved formulations, we instead develop analytic tools to discover which formulations are particularly ill-behaved. Specifically, we examine the growth of approximate (geometric-optics) solutions, studied only in the future domain of dependence of the initial data slice (e.g. we study transients). By evaluating the amplification of transients a given formulation will produce, we may therefore eliminate from consideration the most pathological formulations (e.g. those with numerically-unacceptable amplification). This technique has the potential to provide surprisingly tight constraints on the set of formulations one can safely apply. To illustrate the application of these techniques to practical examples, we apply our technique to the 2-parameter family of evolution equations proposed by Kidder, Scheel, and Teukolsky, focusing in particular on flat space (in Rindler coordinates) and Schwarzchild (in Painleve-Gullstrand coordinates).
Observing the shadow of Einstein-Maxwell-Dilaton-Axion black hole
Wei, Shao-Wen; Liu, Yu-Xiao E-mail: liuyx@lzu.edu.cn
2013-11-01
In this paper, the shadows cast by Einstein-Maxwell-Dilaton-Axion black hole and naked singularity are studied. The shadow of a rotating black hole is found to be a dark zone covered by a deformed circle. For a fixed value of the spin a, the size of the shadow decreases with the dilaton parameter b. The distortion of the shadow monotonically increases with b and takes its maximal when the black hole approaches to the extremal case. Due to the optical properties, the area of the black hole shadow is supposed to equal to the high-energy absorption cross section. Based on this assumption, the energy emission rate is investigated. For a naked singularity, the shadow has a dark arc and a dark spot or straight, and the corresponding observables are obtained. These results show that there is a significant effect of the spin a and dilaton parameter b on these shadows. Moreover, we examine the observables of the shadow cast by the supermassive black hole at the center of the Milky Way, which is very useful for us to probe the nature of the black hole through the astronomical observations in the near future.
Thermodynamics of rotating solutions in (n+1)-dimensional Einstein-Maxwell-dilaton gravity
Sheykhi, A.; Riazi, N.; Pakravan, J.; Dehghani, M. H.
2006-10-15
We construct a class of charged, rotating solutions of (n+1)-dimensional Einstein-Maxwell-dilaton gravity with cylindrical or toroidal horizons in the presence of Liouville-type potentials and investigate their properties. These solutions are neither asymptotically flat nor (anti)-de Sitter. We find that these solutions can represent black brane, with inner and outer event horizons, an extreme black brane or a naked singularity provided the parameters of the solutions are chosen suitably. We also compute temperature, entropy, charge, electric potential, mass and angular momentum of the black brane solutions, and find that these quantities satisfy the first law of thermodynamics. We find a Smarr-type formula and perform a stability analysis by computing the heat capacity in the canonical ensemble. We find that the system is thermally stable when the coupling constant between the dilaton and matter field {alpha}{<=}1, while for {alpha}>1 the system has an unstable phase. This shows that the dilaton field makes the solution unstable, while it is stable even in Lovelock gravity.
An Online Interactive Geometric Database: Including Exact Solutions of Einstein's Field Equations
Mustapha Ishak; Kayll Lake
2001-12-11
We describe a new interactive database (GRDB) of geometric objects in the general area of differential geometry. Database objects include, but are not restricted to, exact solutions of Einstein's field equations. GRDB is designed for researchers (and teachers) in applied mathematics, physics and related fields. The flexible search environment allows the database to be useful over a wide spectrum of interests, for example, from practical considerations of neutron star models in astrophysics to abstract space-time classification schemes. The database is built using a modular and object-oriented design and uses several Java technologies (e.g. Applets, Servlets, JDBC). These are platform-independent and well adapted for applications developed to run over the World Wide Web. GRDB is accompanied by a virtual calculator (GRTensorJ), a graphical user interface to the computer algebra system GRTensorII used to perform online coordinate, tetrad or basis calculations. The highly interactive nature of GRDB allows for systematic internal self-checking and a minimization of the required internal records.
Ren, Jing; Xianyu, Zhong-Zhi; He, Hong-Jian E-mail: xianyuzhongzhi@gmail.com
2014-06-01
We study gravitational interaction of Higgs boson through the unique dimension-4 operator ?H{sup †}HR, with H the Higgs doublet and R the Ricci scalar curvature. We analyze the effect of this dimensionless nonminimal coupling ? on weak gauge boson scattering in both Jordan and Einstein frames. We explicitly establish the longitudinal-Goldstone equivalence theorem with nonzero ? coupling in both frames, and analyze the unitarity constraints. We study the ?-induced weak boson scattering cross sections at O(1?30) TeV scales, and propose to probe the Higgs-gravity coupling via weak boson scattering experiments at the LHC (14 TeV) and the next generation pp colliders (50-100 TeV). We further extend our study to Higgs inflation, and quantitatively derive the perturbative unitarity bounds via coupled channel analysis, under large field background at the inflation scale. We analyze the unitarity constraints on the parameter space in both the conventional Higgs inflation and the improved models in light of the recent BICEP2 data.
Tomas Andrade; William R. Kelly; Donald Marolf
2015-09-17
The gravitational Dirichlet problem -- in which the induced metric is fixed on boundaries at finite distance from the bulk -- is related to simple notions of UV cutoffs in gauge/gravity duality and appears in discussions relating the low-energy behavior of gravity to fluid dynamics. We study the Einstein-Maxwell version of this problem, in which the induced Maxwell potential on the wall is also fixed. For flat walls in otherwise-asymptotically-flat spacetimes, we identify a moduli space of Majumdar-Papapetrou-like static solutions parametrized by the location of an extreme black hole relative to the wall. Such solutions may be described as balancing gravitational repulsion from a negative-mass image-source against electrostatic attraction to an oppositely-signed image charge. Standard techniques for handling divergences yield a moduli space metric with an eigenvalue that becomes negative near the wall, indicating a region of negative kinetic energy and suggesting that the Hamiltonian may be unbounded below. One may also surround the black hole with an additional (roughly spherical) Dirichlet wall to impose a regulator whose physics is more clear. Negative kinetic energies remain, though new terms do appear in the moduli-space metric. The regulator-dependence indicates that the adiabatic approximation may be ill-defined for classical extreme black holes with Dirichlet walls.
Andrade, Tomas; Marolf, Donald
2015-01-01
The gravitational Dirichlet problem -- in which the induced metric is fixed on boundaries at finite distance from the bulk -- is related to simple notions of UV cutoffs in gauge/gravity duality and appears in discussions relating the low-energy behavior of gravity to fluid dynamics. We study the Einstein-Maxwell version of this problem, in which the induced Maxwell potential on the wall is also fixed. For flat walls in otherwise-asymptotically-flat spacetimes, we identify a moduli space of Majumdar-Papapetrou-like static solutions parametrized by the location of an extreme black hole relative to the wall. Such solutions may be described as balancing gravitational repulsion from a negative-mass image-source against electrostatic attraction to an oppositely-signed image charge. Standard techniques for handling divergences yield a moduli space metric with an eigenvalue that becomes negative near the wall, indicating a region of negative kinetic energy and suggesting that the Hamiltonian may be unbounded below. O...
Supersymmetric Asymptotic AdS and Lifshitz Solutions in Einstein-Weyl and Conformal Supergravities
H. Lu; Zhao-Long Wang
2012-05-22
We show that there exist supersymmetric Lifshitz vacua in off-shell Einstein-Weyl supergravity, in addition to the BPS AdS_4 vacuum. The Lifshitz exponents are determined by the product of the cosmological constant and the coupling of the Weyl-squared term. We then obtain the equations of the supersymmetric solutions that are asymptotic to the AdS or Lifshitz vacua. We obtain many examples of exact solutions as well as numerical ones. We find examples of extremal AdS black branes whose near-horizon geometry is AdS_2\\times T^2. We also find an extremal Lifshitz black hole with z=-2, whose horizon coincides with the curvature singularity. However the asymptotic Lifshitz solutions are in general smooth wormholes. In conformal supergravity, we find intriguing examples of non-extremal "BPS" AdS and Lifshitz black holes whose local Killing spinor is divergent on the horizon. We show that all the supersymmetric asymptotic AdS and Lifshitz solutions have the vanishing Noether charge associated with some scaling symmetry. We also study the integrability condition of the Killing spinor equation and the supersymmetric invariance of the action. Finally we show that the only spherically-symmetric BPS solution is the AdS vacuum.
Alberto A. Garcia-Diaz
2013-07-25
The main purpose of this contribution is to determine physical and geometrical characterizations of whole classes of stationary cyclic symmetric gravitational fields coupled to Maxwell electromagnetic fields within the $(2+1)$-dimensional gravity. The physical characterization is based on the determination of the local and global energy-momentum-mass quantities using the Brown-York approach. As far as to the algebraic-geometrical characterization is concerned, the eigenvalue problem for the electromagnetic field, energy-momentum and Cotton tensors is solved and their types are established. The families of Einstein-Maxwell solutions to be considered are: all uniform electromagnetic solutions possessing electromagnetic fields with vanishing covariant derivatives (stationary uniform and spinning Clement classes), all fields having constant electromagnetic field and energy-momentum tensors' invariants (Kamata-Koikawa solutions), the whole classes of hybrid electromagnetic Ayon-Cataldo-Garcia solutions, a new family of stationary electromagnetic solutions, the electrostatic and magnetostatic solutions with Peldan limit, the Clement spinning charged metric, the Martinez-Teitelboim-Zanelli black hole solution, and Dias-Lemos electromagnetic solution.