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1

Physics Out Loud - Quantum Chromodynamics (QCD)  

NLE Websites -- All DOE Office Websites (Extended Search)

Out Loud Main Index Next Video (Short-range Correlations) Short-range Correlations Quantum Chromodynamics (QCD) Elena Long, a graduate student at Kent State University,...

2

Quantum Chromodynamics  

E-Print Network (OSTI)

Quantum chromodynamics is the quantum gauge field theory that describes the strong interactions. This article reviews the basic structure, successes and challenges of quantum chromodynamics as it manifests itself at short and long distances, including the concepts of asymptotic freedom, confinement and infrared safety.

George Sterman

2005-12-27T23:59:59.000Z

3

Lattice Quantum Chromodynamics Project and SCience Gateway at...  

NLE Websites -- All DOE Office Websites (Extended Search)

Lattice Quantum Chromodynamics Lattice Quantum Chromodynamics QCD-BU.jpg Key Challenges: Although the QCD theory has been extensively tested at at high energies, at low energies or...

4

Lattice Quantum Chromodynamics Project and SCience Gateway at...  

NLE Websites -- All DOE Office Websites (Extended Search)

Science at NERSC Nuclear Science Lattice Quantum Chromodynamics Lattice Quantum Chromodynamics Key Challenges: Although the QCD theory has been extensively tested at at...

5

ANL/ALCF/ESP-13/11 Lattice Quantum Chromodynamics  

NLE Websites -- All DOE Office Websites (Extended Search)

1 Lattice Quantum Chromodynamics (SPI, mapping, site ordering, and QPX in Lattice QCD code on Mira) ALCF-2 Early Science Program Technical Report Argonne Leadership Computing...

6

Working group report: Quantum chromodynamics  

Science Conference Proceedings (OSTI)

Recent QCD results for Higgs searches at LHC. V Ravindran ..... One example of particular relevance is the single-spin asymmetry in W boson production,. AL =.

7

Nuclear Forces from Lattice Quantum Chromodynamics  

E-Print Network (OSTI)

A century of coherent experimental and theoretical investigations have uncovered the laws of nature that underly nuclear physics. The standard model of strong and electroweak interactions, with its modest number of input parameters, dictates the dynamics of the quarks and gluons - the underlying building blocks of protons, neutrons, and nuclei. While the analytic techniques of quantum field theory have played a key role in understanding the dynamics of matter in high energy processes, they encounter difficulties when applied to low-energy nuclear structure and reactions, and dense systems. Expected increases in computational resources into the exa-scale during the next decade will provide the ability to numerically compute a range of important strong interaction processes directly from QCD with quantifiable uncertainties using the technique of Lattice QCD. These calculations will refine the chiral nuclear forces that are used as input into nuclear many-body calculations, including the three- and four-nucleon interactions. I discuss the state-of-the-art Lattice QCD calculations of quantities of interest in nuclear physics, progress that is expected in the near future, and the impact upon nuclear physics.

Martin J. Savage

2013-09-18T23:59:59.000Z

8

QCDOC -Quantum Chromodynamics on a Chip at BNL | U.S. DOE Office...  

Office of Science (SC) Website

QCDOC -Quantum Chromodynamics on a Chip at BNL Nuclear Physics (NP) NP Home About Research Facilities Science Highlights Benefits of NP Spinoff Applications Spinoff Archives SBIR...

9

HADRON MASSES IN QUANTUM CHROMODYNAMICS ON THE TRANSVERSE LATTICE  

E-Print Network (OSTI)

representation on the cubic lattice i! llld thm remainFii;. 2: Two amd foor body lattice confil;uratlOO$. 19tllon Chromodynamics """""'""" Lattice National Accelerator

Bardeen, William A.

2013-01-01T23:59:59.000Z

10

QCDOC -Quantum Chromodynamics on a Chip at BNL | U.S. DOE Office of Science  

Office of Science (SC) Website

QCDOC -Quantum Chromodynamics on a Chip QCDOC -Quantum Chromodynamics on a Chip at BNL Nuclear Physics (NP) NP Home About Research Facilities Science Highlights Benefits of NP Spinoff Applications Spinoff Archives SBIR/STTR Applications of Nuclear Science and Technology Funding Opportunities Nuclear Science Advisory Committee (NSAC) News & Resources Contact Information Nuclear Physics U.S. Department of Energy SC-26/Germantown Building 1000 Independence Ave., SW Washington, DC 20585 P: (301) 903-3613 F: (301) 903-3833 E: sc.np@science.doe.gov More Information » Spinoff Archives QCDOC -Quantum Chromodynamics on a Chip at BNL Print Text Size: A A A RSS Feeds FeedbackShare Page Application/instrumentation: Advanced high capacity computing for quantum chromodynamics Developed at: Brookhaven National Laboratory, Columbia, IBM, RIKEN

11

Neutral B-meson mixing from three-flavor lattice quantum chromodynamic...  

NLE Websites -- All DOE Office Websites (Extended Search)

Neutral B-meson mixing from three-flavor lattice quantum chromodynamics: Determination of the SU(3)-breaking ratio Submitted by mkaczmar on February 8, 2013 - 15:02 Authors: A....

12

Exotic mesons from quantum chromodynamics with improved gluon and quark actions on the anisotropic lattice  

E-Print Network (OSTI)

Hybrid (exotic) mesons, which are important predictions of quantum chromodynamics (QCD), are states of quarks and anti-quarks bound by excited gluons. First principle lattice study of such states would help us understand the role of ``dynamical'' color in low energy QCD and provide valuable information for experimental search for these new particles. In this paper, we apply both improved gluon and quark actions to the hybrid mesons, which might be more efficient than the previous works in reducing lattice spacing error and finite volume effect. Quenched simulations were done at $\\beta=2.6$ and on a $\\xi=3$ anisotropic $12^3 \\times 36$ lattice using our PC cluster. We obtain $2013 \\pm 26 \\pm 71$ MeV for the mass of the $1^{-+}$ hybrid meson ${\\bar q}qg$ in the light quark sector, and $4369 \\pm 37 \\pm 99$Mev in the charm quark sector; the mass splitting between the $1^{-+}$ hybrid meson ${\\bar c}c g$ in the charm quark sector and the spin averaged S-wave charmonium mass is estimated to be $1302 \\pm 37 \\pm 99$ M...

Mei, Z H; Mei, Zhong-Hao; Luo, Xiang-Qian

2003-01-01T23:59:59.000Z

13

Murray Gell-Mann, the Eightfold Way, Quarks, and Quantum Chromodynamics  

Office of Scientific and Technical Information (OSTI)

Murray Gell-Mann, the Eightfold Way, and Quantum Chromodynamics Murray Gell-Mann, the Eightfold Way, and Quantum Chromodynamics Resources with Additional Information Murray Gell-Mann Courtesy of the Santa Fe Institute 'In 1969, Professor Gell-Mann received the Nobel Prize in physics for his work on the theory of elementary particles. Professor Gell-Mann's "eightfold way" theory brought order to the chaos created by the discovery of some 100 particles in the atom's nucleus. Then he found that all of those particles, including the neutron and proton, are composed of fundamental building blocks that he named "quarks." The quarks are permanently confined by forces coming from the exchange of "gluons." He and others later constructed the quantum field theory of quarks and gluons, called "quantum chromodynamics," which seems to account for all the nuclear particles and their strong interactions." ...

14

Calculation of the nucleon axial charge in lattice QCD  

SciTech Connect

Protons and neutrons have a rich structure in terms of their constituents, the quarks and gluons. Understanding this structure requires solving Quantum Chromodynamics (QCD). However QCD is extremely complicated, so we must numerically solve the equations of QCD using a method known as lattice QCD. Here we describe a typical lattice QCD calculation by examining our recent computation of the nucleon axial charge.

D. B. Renner; R. G. Edwards; G. Fleming; Ph. Hagler; J. W. Negele; K. Orginos; A. V. Pochinsky; D. G. Richards; W. Schroers

2006-09-01T23:59:59.000Z

15

Strongly Correlated Quantum Fluids: Ultracold Quantum Gases, Quantum Chromodynamic Plasmas, and Holographic Duality  

E-Print Network (OSTI)

Strongly correlated quantum fluids are phases of matter that are intrinsically quantum mechanical, and that do not have a simple description in terms of weakly interacting quasi-particles. Two systems that have recently attracted a great deal of interest are the quark-gluon plasma, a plasma of strongly interacting quarks and gluons produced in relativistic heavy ion collisions, and ultracold atomic Fermi gases, very dilute clouds of atomic gases confined in optical or magnetic traps. These systems differ by more than 20 orders of magnitude in temperature, but they were shown to exhibit very similar hydrodynamic flow. In particular, both fluids exhibit a robustly low shear viscosity to entropy density ratio which is characteristic of quantum fluids described by holographic duality, a mapping from strongly correlated quantum field theories to weakly curved higher dimensional classical gravity. This review explores the connection between these fields, and it also serves as an introduction to the Focus Issue of New Journal of Physics on Strongly Correlated Quantum Fluids: from Ultracold Quantum Gases to QCD Plasmas. The presentation is made accessible to the general physics reader and includes discussions of the latest research developments in all three areas.

Allan Adams; Lincoln D. Carr; Thomas Schaefer; Peter Steinberg; John E. Thomas

2012-05-23T23:59:59.000Z

16

Two-photon exclusive processes in quantum chromodynamics  

SciTech Connect

QCD predictions for ..gamma gamma.. annihilation into single mesons, meson pairs, and baryon pairs are reviewed. Two-photon exclusive processes provide the most sensitive and practical measure of the distribution amplitudes, and thus a critical confrontation between QCD and experiment. Both the angular distribution and virtual photon mass dependence of these amplitudes are sensitive to the shapes of the phi (chi, Q). Novel effects involving the production of qq anti q anti q states at threshold are also discussed, and a new method is presented for systematically incorporating higher-order QCD corrections in ..gamma gamma.. reactions.

Brodsky, S.J.

1986-07-01T23:59:59.000Z

17

Bosonic and Baryonic String Theory in Quantum Chromodynamics  

Science Conference Proceedings (OSTI)

Bosonic string formation in gauge theories is reviewed with particular attention to the confining flux in lattice QCD and its effective string theory description. Recent results on the Casimir energy of the ground state and the string excitation spectrum are analyzed in the Dirichlet string limit of large separation between static sources. The closed string-soliton (torelon) with electric flux winding around a compact dimension is discussed and a new bound state tower spectrum at baryon string junctions is presented.

Kuti, Julius [Department of Physics, University of California, San Diego, La Jolla, California 92093 (United States)

2007-02-27T23:59:59.000Z

18

Hadronic Resonances from Lattice QCD  

Science Conference Proceedings (OSTI)

The determination of the pattern of hadronic resonances as predicted by Quantum Chromodynamics requires the use of non-perturbative techniques. Lattice QCD has emerged as the dominant tool for such calculations, and has produced many QCD predictions which can be directly compared to experiment. The concepts underlying lattice QCD are outlined, methods for calculating excited states are discussed, and results from an exploratory Nucleon and Delta baryon spectrum study are presented.

John Bulava; Robert Edwards; George Fleming; K. Jimmy Juge; Adam C. Lichtl; Nilmani Mathur; Colin Morningstar; David Richards; Stephen J. Wallace

2007-06-16T23:59:59.000Z

19

Strongly correlated quantum fluids: ultracold quantum gases, quantum chromodynamic plasmas and holographic duality  

E-Print Network (OSTI)

Strongly correlated quantum fluids are phases of matter that are intrinsically quantum mechanical and that do not have a simple description in terms of weakly interacting quasiparticles. Two systems that have recently ...

Adams, Allan

20

Parallelizing the QUDA Library for Multi-GPU Calculations in Lattice Quantum Chromodynamics  

Science Conference Proceedings (OSTI)

Graphics Processing Units (GPUs) are having a transformational effect on numerical lattice quantum chromodynamics (LQCD) calculations of importance in nuclear and particle physics. The QUDA library provides a package of mixed precision sparse matrix linear solvers for LQCD applications, supporting single GPUs based on NVIDIA's Compute Unified Device Architecture (CUDA). This library, interfaced to the QDP++/Chroma framework for LQCD calculations, is currently in production use on the "9g" cluster at the Jefferson Laboratory, enabling unprecedented price/performance for a range of problems in LQCD. Nevertheless, memory constraints on current GPU devices limit the problem sizes that can be tackled. In this contribution we describe the parallelization of the QUDA library onto multiple GPUs using MPI, including strategies for the overlapping of communication and computation. We report on both weak and strong scaling for up to 32 GPUs interconnected by InfiniBand, on which we sustain in excess of 4 Tflops.

Ronald Babich, Michael Clark, Balint Joo

2010-11-01T23:59:59.000Z

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


21

Color transparency and the structure of the proton in quantum chromodynamics  

SciTech Connect

Many anomalies suggest that the proton itself is a much more complex object than suggested by simple non-relativistic quark models. Recent analyses of the proton distribution amplitude using QCD sum rules points to highly-nontrivial proton structure. Solutions to QCD in one-space and one-time dimension suggest that the momentum distributions of non-valence quarks in the hadrons have a non-trivial oscillatory structure. The data seems also to be suggesting that the intrinsic'' bound state structure of the proton has a non-negligible strange and charm quark content, in addition to the extrinsic'' sources of heavy quarks created in the collision itself. As we shall see in this lecture, the apparent discrepancies with experiment are not so much a failure of QCD, but rather symptoms of the complexity and richness of the theory. An important tool for analyzing this complexity is the light-cone Fock state representation of hadron wavefunctions, which provides a consistent but convenient framework for encoding the features of relativistic many-body systems in quantum field theory. 121 refs., 44 figs., 1 tab.

Brodsky, S.J.

1989-06-01T23:59:59.000Z

22

Scaling lattice QCD beyond 100 GPUs  

Science Conference Proceedings (OSTI)

Over the past five years, graphics processing units (GPUs) have had a transformational effect on numerical lattice quantum chromodynamics (LQCD) calculations in nuclear and particle physics. While GPUs have been applied with great success to the post-Monte ... Keywords: GPU, Krylov solvers, domain decomposition, lattice QCD

R. Babich; M. A. Clark; B. Joó; G. Shi; R. C. Brower; S. Gottlieb

2011-11-01T23:59:59.000Z

23

Nuclear Physics from Lattice QCD  

NLE Websites -- All DOE Office Websites (Extended Search)

Physics from Lattice QCD Physics from Lattice QCD Resources at NERSC Martin J. Savage, Robert Edwards and Chip Watson May 2011, Washington D.C. Science : 20 mins : Martin Savage Hardware : 15 mins : Chip Watson Code, Algorithms, Production : 35 mins : Robert Edwards (Massimo DiPierro) Topological Charge Density Thursday, May 26, 2011 Spin-pairing Shell-structure Vibrational and rotational excitations Λ QCD m u Λ QCD m d Λ QCD m s Λ QCD α e Small number of input parameters responsible for all of strongly interacting matter Quarks and Gluons Proton Nucleus The Structure and Interactions of Matter from Quantum Chromodynamics Thursday, May 26, 2011 Exa-Scale Computational Resources Nuclear Astrophysics Accelerator Physics

24

The Scale of Dark QCD  

E-Print Network (OSTI)

Most of the mass of ordinary matter has its origin from quantum chromodynamics (QCD). A similar strong dynamics, dark QCD, could exist to explain the mass origin of dark matter. Using infrared fixed points of the two gauge couplings, we provide a dynamical mechanism that relates the dark QCD confinement scale to our QCD scale, and hence provides an explanation for comparable dark baryon and proton masses. Together with a mechanism that generates equal amounts of dark baryon and ordinary baryon asymmetries in the early universe, the similarity of dark matter and ordinary matter energy densities can be naturally explained. For a large class of gauge group representations, the particles charged under both QCD and dark QCD, necessary ingredients for generating the infrared fixed points, are found to have masses at one to two TeV, which sets the scale for dark matter direct detection and novel collider signatures involving visible and dark jets.

Yang Bai; Pedro Schwaller

2013-06-19T23:59:59.000Z

25

High Energy Physics Division, ANL Lattice QCD  

NLE Websites -- All DOE Office Websites (Extended Search)

Energy Energy Physics Division, ANL Lattice QCD in extreme environments D. K. Sinclair (HEP, Argonne) J. B. Kogut (Physics, Illinois) D. Toublan (Physics, Illinois) 1 Lattice QCD Quantum chromodynamics(QCD) de- scribes Hadrons and their strong inter- actions. Hadrons consist of quarks held together by gluons. Lattice QCD is QCD on a 4-dimensional (space-time) lattice. Allows numerical simulation of the functional integrals which define this quantum field theory, and non-perturbative QCD calculations. Physics - properties of hadrons (masses, etc.), hadronic matrix elements (HEP), hadronic matter at finite temperature and/or densities (RHIC, early universe, neutron stars). 2 Computational Methods * Functional integral is mapped to the partition function for a classical sys- tem. Molecular-dynamics methods are used to calculate the observables for this classical system.

26

Challenges to quantum chromodynamics: Anomalous spin, heavy quark, and nuclear phenomena  

SciTech Connect

The general structure of QCD meshes remarkably well with the facts of the hadronic world, especially quark-based spectroscopy, current algebra, the approximate point-like structure of large momentum transfer inclusive reactions, and the logarithmic violation of scale invariance in deep inelastic lepton-hadron reactions. QCD has been successful in predicting the features of electron-positron and photon-photon annihilation into hadrons, including the magnitude and scaling of the cross sections, the shape of the photon structure function, the production of hadronic jets with patterns conforming to elementary quark and gluon subprocesses. The experimental measurements appear to be consistent with basic postulates of QCD, that the charge and weak currents within hadrons are carried by fractionally-charged quarks, and that the strength of the interactions between the quarks, and gluons becomes weak at short distances, consistent with asymptotic freedom. Nevertheless in some cases, the predictions of QCD appear to be in dramatic conflict with experiment. The anomalies suggest that the proton itself as a much more complex object than suggested by simple non-relativistic quark models. Recent analyses of the proton distribution amplitude using QCD sum rules points to highly-nontrival proton structure. Solutions to QCD in one-space and one-time dimension suggest that the momentum distributions of non-valence quarks in the hadrons have a non-trival oscillatory structure. The data seems also to be suggesting that the intrinsic'' bound state structure of the proton has a non- negligible strange and charm quark content, in addition to the extrinsic'' sources of heavy quarks created in the collision itself. 144 refs., 46 figs., 2 tabs.

Brodsky, S.J.

1989-11-01T23:59:59.000Z

27

The BlueGene/L Supercomputer and Quantum ChromoDynamics  

SciTech Connect

In summary our update contains: (1) Perfect speedup sustaining 19.3% of peak for the Wilson D D-slash Dirac operator. (2) Measurements of the full Conjugate Gradient (CG) inverter that inverts the Dirac operator. The CG inverter contains two global sums over the entire machine. Nevertheless, our measurements retain perfect speedup scaling demonstrating the robustness of our methods. (3) We ran on the largest BG/L system, the LLNL 64 rack BG/L supercomputer, and obtained a sustained speed of 59.1 TFlops. Furthermore, the speedup scaling of the Dirac operator and of the CG inverter are perfect all the way up to the full size of the machine, 131,072 cores (please see Figure II). The local lattice is rather small (4 x 4 x 4 x 16) while the total lattice has been a lattice QCD vision for thermodynamic studies (a total of 128 x 128 x 256 x 32 lattice sites). This speed is about five times larger compared to the speed we quoted in our submission. As we have pointed out in our paper QCD is notoriously sensitive to network and memory latencies, has a relatively high communication to computation ratio which can not be overlapped in BGL in virtual node mode, and as an application is in a class of its own. The above results are thrilling to us and a 30 year long dream for lattice QCD.

Vranas, P; Soltz, R

2006-10-19T23:59:59.000Z

28

Nuclear Physics from Lattice QCD  

E-Print Network (OSTI)

We review recent progress toward establishing lattice Quantum Chromodynamics as a predictive calculational framework for nuclear physics. A survey of the current techniques that are used to extract low-energy hadronic scattering amplitudes and interactions is followed by a review of recent two-body and few-body calculations by the NPLQCD collaboration and others. An outline of the nuclear physics that is expected to be accomplished with Lattice QCD in the next decade, along with estimates of the required computational resources, is presented.

S. R. Beane; W. Detmold; K. Orginos; M. J. Savage

2010-04-17T23:59:59.000Z

29

Meson-baryon sigma terms in QCD Sum Rules  

E-Print Network (OSTI)

We evaluate the pion-nucleon and the pion-Delta sigma terms by employing the method of quantum chromodynamics (QCD) sum rules. The obtained value of the pion-nucleon sigma term is compatible with the larger values already anticipated by the recent calculations. It is also found that the pion-Delta sigma term is as large as the pion-nucleon sigma term.

G. Erkol; M. Oka

2007-05-28T23:59:59.000Z

30

BNL | QCD Matter, Big Bang Physics  

NLE Websites -- All DOE Office Websites (Extended Search)

QCD Matter QCD Matter image Physicist Paul Sorensen next to the STAR detector at Brookhaven's Relativistic Heavy Ion Collider Exploring Matter at the Dawn of Time Brookhaven Lab leads the world in exploring how the matter that makes up atomic nuclei behaved just after the Big Bang. At that time, more than 13 billion years ago, there were no protons and neutrons-just a sea of "free" quarks and gluons, fundamental particles whose interactions are governed by nature's strongest force and described by the theory of quantum chromodynamics (QCD). More than 1,000 scientists from around the nation and the world come to Brookhaven to recreate this "quark-gluon plasma" by accelerating heavy ions (atoms stripped of their electrons) to nearly the speed of light and smashing them together at the Lab's

31

QCD measurements at the Tevatron  

E-Print Network (OSTI)

Selected quantum chromodynamics (QCD) measurements performed at the Fermilab Run II Tevatron ppbar collider running at sqrt{s} = 1.96 TeV by CDF and D0 Collaborations are presented. The inclusive jet, dijet production and three-jet cross section measurements are used to test perturbative QCD calculations, constrain parton distribution function (PDF) determinations, and extract a precise value of the strong coupling constant, alpha_s(m_Z) = 0.1161^{+0.0041}_{-0.0048}. Inclusive photon production cross-section measurements reveal an inability of next-to-leading-order (NLO) perturbative QCD (pQCD) calculations to describe low-energy photons arising directly in the hard scatter. The diphoton production cross-sections check the validity of the NLO pQCD predictions, soft-gluon resummation methods implemented in theoretical calculations, and contributions from the parton-to-photon fragmentation diagrams. Events with W/Z+jets productions are used to measure many kinematic distributions allowing extensive tests and tu...

,

2011-01-01T23:59:59.000Z

32

Quantum chromodynamics and nuclear physics at extreme energy density. Progress report, May 15, 1993--May 14, 1994  

SciTech Connect

This report briefly discusses the following topics: quark-gluon plasma and high-energy collisions; hadron structure and chiral dynamics; nonperturbative studies and nonabelian gauge theories; and studies in quantum field theory.

Mueller, B.; Springer, R.P.

1994-05-15T23:59:59.000Z

33

qcd.dvi  

NLE Websites -- All DOE Office Websites (Extended Search)

Written Written October 2009 by G. Dissertori (ETH, Zurich) and G.P. Salam (LPTHE, Paris). 1.1. Basics Quantum Chromodynamics (QCD), the gauge field theory that describes the strong interactions of colored quarks and gluons, is the SU(3) component of the SU(3)×SU(2)×U(1) Standard Model of Particle Physics. The Lagrangian of QCD is given by L = q ¯ ψ q,a iγ µ ∂ µ δ ab - g s γ µ t C ab A C µ - m q δ ab ψ q,b - 1 4 F A µν F A µν , (1.1) where repeated indices are summed over. The γ µ are the Dirac γ-matrices. The ψ q,a are quark-field spinors for a quark of flavor q and mass m q , with a color-index a that runs from a = 1 to N c = 3, i.e. quarks come in three "colors." Quarks are said to be in the fundamental representation of the SU(3) color group. The A C µ correspond to the gluon fields, with C running from 1 to N 2 c - 1 = 8, i.e. there are eight kinds of gluon. Gluons are said to be in the adjoint representation

34

qcd.dvi  

NLE Websites -- All DOE Office Websites (Extended Search)

Revised Revised October 2013 by S. Bethke (Max-Planck-Institute of Physics, Munich), G. Dissertori (ETH, Zurich) and G.P. Salam (CERN). 1.1. Basics Quantum Chromodynamics (QCD), the gauge field theory that describes the strong interactions of colored quarks and gluons, is the SU(3) component of the SU(3)×SU(2)×U(1) Standard Model of Particle Physics. The Lagrangian of QCD is given by L = q ¯ ψ q,a iγ µ ∂ µ δ ab - g s γ µ t C ab A C µ - m q δ ab ψ q,b - 1 4 F A µν F A µν , (1.1) where repeated indices are summed over. The γ µ are the Dirac γ-matrices. The ψ q,a are quark-field spinors for a quark of flavor q and mass m q , with a color-index a that runs from a = 1 to N c = 3, i.e. quarks come in three "colors." Quarks are said to be in the fundamental representation of the SU(3) color group. The A C µ correspond to the gluon fields, with C running from 1 to N 2 c - 1 = 8, i.e. there are eight kinds of

35

TESTS OF COHERENT QCD PHENOMENA AND NUCLEON SUBSTRUCTURE AT CEBAF  

E-Print Network (OSTI)

Measurements of exclusive processes such as electroproduction, photoproduction, and Compton scattering are among the most sensitive probes of proton structure and coherent phenomena in quantum chromodynamics. The continuous electron beam at CEBAF, upgraded in laboratory energy to 10–12 GeV, will allow a systematic study of exclusive, semi-inclusive, and inclusive reactions in a kinematic range well-tuned to the study of fundamental nucleon and nuclear substructure. I also discuss the potential at CEBAF for studying novel QCD phenomena at the charm production threshold, including the possible production of nuclear-bound quarkonium.

Stanley J. Brodsky; Cebaf Workshop On Electroproduction; Stanley J. Brodsky

1994-01-01T23:59:59.000Z

36

Nuclear chromodynamics is not the colorization of nuclear physics  

SciTech Connect

The successful description of nuclei in terms of nucleons, deltas and mesons provides an enormous challenge to QCD. It compels us to pursue our theoretical understanding of chromodynamics into the realm of multiple color singlets in order to examine the concept of color saturation. To pursue this theme, we examine the idea of nuclear transparency in the light of models for confinement and describe the formulation of lattice simulations sensitive to exchange forces. 22 refs., 7 figs.

Sivers, D.

1988-07-19T23:59:59.000Z

37

Workshop on nuclear chromodynamics: Quarks and gluons in particles and nuclei  

SciTech Connect

The assertion that quantum chromodynamics (QCD) is the correct theory describing strong interaction phenomena has, largely by repetition, become rather non-controversial. It is likely even true. However, whether or not it is correct in detail, the experimentally supported realization that colored quarks and gluons are the elementary degrees of freedom, that asymptotic freedom makes short distance phenomena rather ''simple'' to understand, and that color is confined on the hadronic length scale of -- 1 fm has led to a profound change in the character of our attempts to understand the structure and interactions of both hadrons and nuclei. Many of the most important issued in particle physics and in nuclear physics are now seen to be intimately connected. An understanding of the validity and limits of effective theories based upon hadron degrees of freedom, so phenomenologically successful in describing a host of low energy phenomena, is coming into focus. The existence of new forms of matter grounded in the hidden color degree of freedom is predicted. These considerations form the subject of nuclear chromodynamics (NCD). The subject is far from mature and is developing rapidly.

Brodsky, S.; Moniz, E.

1985-01-01T23:59:59.000Z

38

Physics Out Loud - Proton  

NLE Websites -- All DOE Office Websites (Extended Search)

Photomultiplier Tube Previous Video (Photomultiplier Tube) Physics Out Loud Main Index Next Video (Quantum Chromodynamics (QCD)) Quantum Chromodynamics (QCD) Proton Learn about the...

39

Physics Out Loud - Short-range Correlations  

NLE Websites -- All DOE Office Websites (Extended Search)

Quantum Chromodynamics (QCD) Previous Video (Quantum Chromodynamics (QCD)) Physics Out Loud Main Index Next Video (SRF Accelerator Cavities) SRF Accelerator Cavities Short-range...

40

QCD, Tevatron results and LHC prospects  

SciTech Connect

We present a summary of the most recent measurements relevant to Quantum Chromodynamics (QCD) delivered by the D0 and CDF Tevatron experiments by May 2008. CDF and D0 are moving toward precision measurements of QCD based on data samples in excess of 1 fb-1. The inclusive jet cross sections have been extended to forward rapidity regions and measured with unprecedented precision following improvements in the jet energy calibration. Results on dijet mass distributions, bbbar dijet production using tracker based triggers, underlying event in dijet and Drell-Yan samples, inclusive photon and diphoton cross sections complete the list of measurements included in this paper. Good agreement with pQCD within errors is observed for jet production measurements. An improved and consistent theoretical description is needed for photon+jets processes. Collisions at the LHC are scheduled for early fall 2008, opening an era of discoveries at the new energy frontier, 5-7 times higher than that of the Tevatron.

Elvira, V.Daniel; /Fermilab

2008-08-01T23:59:59.000Z

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


41

Perturbative QCD signatures of hybrid hadrons in electroproduction at high Q{sup 2}  

SciTech Connect

In the perturbative domain of quantum chromodynamics (QCD), transverse electroproduction of hybrid baryons is small. Their longitudinal electroproduction has size and scaling behavior like normal baryons. Thus deep inelastic scattering has hybrid resonance peak to background ratio small for the transverse structure function but normal size and constant for the longitudinal one. This signature can test if the Roper resonance is a hybrid. Related high momentum transfer signatures may clarify the structure of possible non-standard states such as {Lambda}(1405), f{sub o}(975), or a{sub o}(980).

Carlson, C.E. [Washington Univ., Seattle, WA (United States). Inst. for Nuclear Theory]|[College of William and Mary, Williamsburg, VA (United States). Dept. of Physics; Mukhopadhyay, N.C. [Washington Univ., Seattle, WA (United States). Inst. for Nuclear Theory]|[Rensselaer Polytechnic Inst., Troy, NY (United States). Dept. of Physics

1991-08-01T23:59:59.000Z

42

Exclusive Processes: Tests of Coherent QCD Phenomena and Nucleon Substructure at CEBAF -  

E-Print Network (OSTI)

Measurements of exclusive processes such as electroproduction, photoproduction, and Compton scattering are among the most sensitive probes of proton structure and coherent phenomena in quantum chromodynamics. The continuous electron beam at CEBAF, upgraded in laboratory energy to 10--12 GeV, will allow a systematic study of exclusive, semi-inclusive, and inclusive reactions in a kinematic range well-tuned to the study of fundamental nucleon and nuclear substructure. I also discuss the potential at CEBAF for studying novel QCD phenomena at the charm production threshold, including the possible production of nuclear-bound quarkonium.

Stanley J. Brodsky; SLAC

1994-07-22T23:59:59.000Z

43

Perturbative QCD signatures of hybrid hadrons in electroproduction at high Q sup 2  

SciTech Connect

In the perturbative domain of quantum chromodynamics (QCD), transverse electroproduction of hybrid baryons is small. Their longitudinal electroproduction has size and scaling behavior like normal baryons. Thus deep inelastic scattering has hybrid resonance peak to background ratio small for the transverse structure function but normal size and constant for the longitudinal one. This signature can test if the Roper resonance is a hybrid. Related high momentum transfer signatures may clarify the structure of possible non-standard states such as {Lambda}(1405), f{sub o}(975), or a{sub o}(980).

Carlson, C.E. (Washington Univ., Seattle, WA (United States). Inst. for Nuclear Theory College of William and Mary, Williamsburg, VA (United States). Dept. of Physics); Mukhopadhyay, N.C. (Washington Univ., Seattle, WA (United States). Inst. for Nuclear Theory Rensselaer Polytechnic Inst., Troy, NY (United States). Dept. of Physics)

1991-08-01T23:59:59.000Z

44

Physics of the 1 Teraflop RIKEN-BNL-Columbia QCD project. Proceedings of RIKEN BNL Research Center workshop: Volume 13  

SciTech Connect

A workshop was held at the RIKEN-BNL Research Center on October 16, 1998, as part of the first anniversary celebration for the center. This meeting brought together the physicists from RIKEN-BNL, BNL and Columbia who are using the QCDSP (Quantum Chromodynamics on Digital Signal Processors) computer at the RIKEN-BNL Research Center for studies of QCD. Many of the talks in the workshop were devoted to domain wall fermions, a discretization of the continuum description of fermions which preserves the global symmetries of the continuum, even at finite lattice spacing. This formulation has been the subject of analytic investigation for some time and has reached the stage where large-scale simulations in QCD seem very promising. With the computational power available from the QCDSP computers, scientists are looking forward to an exciting time for numerical simulations of QCD.

1998-10-16T23:59:59.000Z

45

QCD Results from the Fermilab Tevatron proton-antiproton Collider  

E-Print Network (OSTI)

Selected recent quantum chromodynamics (QCD) measurements are reviewed for Fermilab Run II Tevatron proton-antiproton collisions studied by the Collider Detector at Fermilab (CDF) and DZero Collaborations at a centre-of-mass energy of sqrt{s}=1.96 TeV. Tantamount to Rutherford scattering studies at the TeV scale, inclusive jet and dijet production cross-section measurements are used to seek and constrain new particle physics phenomena, test perturbative QCD calculations, inform parton distribution function (PDF) determinations, and extract a precise value of the strong coupling constant, alpha_s(m_Z) = 0.1161^{+0.0041}_{-0.0048}. Inclusive photon production cross-section measurements reveal an inability of next-to-leading-order (NLO) perturbative QCD (pQCD) calculations to describe low-energy photons arising directly in the hard scatter. Events with gamma + 3-jet configurations are used to measure the increasingly important double parton scattering (DPS) phenomenon, with an obtained effective interaction cros...

Warburton, Andreas

2010-01-01T23:59:59.000Z

46

CTEQ6 Parton Distribution Functions from the Coordinated Theoretical-Experimental Project on QCD  

DOE Data Explorer (OSTI)

The Coordinated Theoretical-Experimental Project on QCD is a multi-institutional collaboration devoted to a broad program of research projects and cooperative enterprises in high-energy physics centered on Quantum Chromodynamics (QCD) and its implications in all areas of the Standard Model and beyond. The Collaboration consists of 32 theorists and experimentalists at 18 universities and 5 national laboratories. More than 65 sets of Parton Distribution Functions are available for public access. Read the summary at http://hep.pa.msu.edu/cteq/public/fortran/Cteq6Pdf-2008.txt to understand and connect to the research behind these data. Links to many online software tools, information about Parton Distribution Functions, papers, and other resources are also available.

Huston, Joey [Co-Spokesperson; Ownes, Joseph [Co-Spokesperson

47

A link between measured neutron star masses and lattice QCD data  

E-Print Network (OSTI)

We study the hadron-quark phase transition in neutron star matter and the structural properties of hybrid stars using an equation of state (EOS) for the quark phase derived with the field correlator method (FCM). We make use of the measured neutron star masses, and particularly the mass of PSR J1614-2230, to constrain the values of the gluon condensate $G_2$ which is one of the EOS parameter within the FCM. We find that the values of $G_2$ extracted from the mass measurement of PSR J1614-2230 are fully consistent with the values of the same quantity derived, within the FCM, from recent lattice quantum chromodynamics (QCD) calculations of the deconfinement transition temperature at zero baryon chemical potential. The FCM thus provides a powerful tool to link numerical calculations of QCD on a space-time lattice with neutron stars physics.

Ignazio Bombaci; Domenico Logoteta

2012-12-24T23:59:59.000Z

48

Working group report: Quantum chromodynamics - Springer  

Science Conference Proceedings (OSTI)

(quark/anti-quark) and for Higgs production through gluon fusion, I = g (gluon) and for bottom quark annihilation to Higgs boson, I = b (bottom quark). Here. ?I.

49

Light-Front Holographic QCD  

SciTech Connect

The relation between the hadronic short-distance constituent quark and gluon particle limit and the long-range confining domain is yet one of the most challenging aspects of particle physics due to the strong coupling nature of Quantum Chromodynamics, the fundamental theory of the strong interactions. The central question is how one can compute hadronic properties from first principles; i.e., directly from the QCD Lagrangian. The most successful theoretical approach thus far has been to quantize QCD on discrete lattices in Euclidean space-time. Lattice numerical results follow from computation of frame-dependent moments of distributions in Euclidean space and dynamical observables in Minkowski spacetime, such as the time-like hadronic form factors, are not amenable to Euclidean lattice computations. The Dyson-Schwinger methods have led to many important insights, such as the infrared fixed point behavior of the strong coupling constant, but in practice, the analyses are limited to ladder approximation in Landau gauge. Baryon spectroscopy and the excitation dynamics of nucleon resonances encoded in the nucleon transition form factors can provide fundamental insight into the strong-coupling dynamics of QCD. New theoretical tools are thus of primary interest for the interpretation of the results expected at the new mass scale and kinematic regions accessible to the JLab 12 GeV Upgrade Project. The AdS/CFT correspondence between gravity or string theory on a higher-dimensional anti-de Sitter (AdS) space and conformal field theories in physical space-time has led to a semiclassical approximation for strongly-coupled QCD, which provides physical insights into its nonperturbative dynamics. The correspondence is holographic in the sense that it determines a duality between theories in different number of space-time dimensions. This geometric approach leads in fact to a simple analytical and phenomenologically compelling nonperturbative approximation to the full light-front QCD Hamiltonian 'Light-Front Holography'. Light-Front Holography is in fact one of the most remarkable features of the AdS/CFT correspondence. The Hamiltonian equation of motion in the light-front (LF) is frame independent and has a structure similar to eigenmode equations in AdS space. This makes a direct connection of QCD with AdS/CFT methods possible. Remarkably, the AdS equations correspond to the kinetic energy terms of the partons inside a hadron, whereas the interaction terms build confinement and correspond to the truncation of AdS space in an effective dual gravity approximation. One can also study the gauge/gravity duality starting from the bound-state structure of hadrons in QCD quantized in the light-front. The LF Lorentz-invariant Hamiltonian equation for the relativistic bound-state system is P{sub {mu}}P{sup {mu}}|{psi}(P)> = (P{sup +}P{sup -} - P{sub {perpendicular}}{sup 2})|{psi}(P)> = M{sup 2}|{psi}(P)>, P{sup {+-}} = P{sup 0} {+-} P{sup 3}, where the LF time evolution operator P{sup -} is determined canonically from the QCD Lagrangian. To a first semiclassical approximation, where quantum loops and quark masses are not included, this leads to a LF Hamiltonian equation which describes the bound-state dynamics of light hadrons in terms of an invariant impact variable {zeta} which measures the separation of the partons within the hadron at equal light-front time {tau} = x{sup 0} + x{sup 3}. This allows us to identify the holographic variable z in AdS space with an impact variable {zeta}. The resulting Lorentz-invariant Schroedinger equation for general spin incorporates color confinement and is systematically improvable. Light-front holographic methods were originally introduced by matching the electromagnetic current matrix elements in AdS space with the corresponding expression using LF theory in physical space time. It was also shown that one obtains identical holographic mapping using the matrix elements of the energy-momentum tensor by perturbing the AdS metric around its static solution. A gravity dual to QCD is not known, but th

Brodsky, Stanley J.; /SLAC /Southern Denmark U., CP3-Origins; de Teramond, Guy F.; /Costa Rica U.

2012-02-16T23:59:59.000Z

50

Beam Energy Scan program at RHIC-experimental approach to the QCD Phase Diagram  

SciTech Connect

The Beam Energy Scan (BES) program at RHIC was launched with the specific aim to explore the QCD (Quantum Chromodynamics) Phase Diagram. Particular emphasis was given to the search for phase boundaries and the location of the Critical Point (CP). The first run with AuAu collisions at 7.7, 11.5, and 39 GeV took place in 2010, and the next one, with energies of 18 and 27 GeV, will start in a few months. The results of the first stage of the BES program obtained by the STAR (Solenoidal Tracker at RHIC) experiment are presented and discussed, as well as plans for the future of the program.

Odyniec, G., E-mail: G_Odyniec@lbl.gov [Lawrence Berkeley National Laboratory (United States)

2012-05-15T23:59:59.000Z

51

Fluctuations of Chromodynamic Fields in Quark-Gluon Plasma  

E-Print Network (OSTI)

Chromodynamic fluctuations in the collisionless quark-gluon plasma are found as a solution of the initial value linearized problem. The stable and unstable plasmas are discussed.

Mrowczynski, Stanislaw

2008-01-01T23:59:59.000Z

52

The QCD phase diagram from Schwinger-Dyson Equations  

E-Print Network (OSTI)

We study the phase diagram of quantum chromodynamics (QCD). For this purpose we employ the Schwinger-Dyson equations (SDEs) technique and construct a truncation of the infinite tower of equations by demanding a matching with the lattice results for the quark-anti-quark condensate at finite temperature (T), for zero quark chemical potential (mu), that is, the region where lattice calculations are expected to provide reliable results. We compute the evolution of the phase diagram away from T=0 for increasing values of the chemical potential by following the evolution of the heat capacity as a function of T and mu. The behavior of this thermodynamic variable clearly demonstrates the existence of a cross-over for mu less than a critical value. However, the heat capacity develops a singularity near mu approx 0.22 GeV marking the onslaught of a first order phase transition characterized by the existence of a critical point. The critical line continues until mu approx 0.53 GeV where Tc=0 and thus chiral symmetry is finally restored.

Enif Gutierrez; Aftab Ahmad; Alejandro Ayala; Adnan Bashir; Alfredo Raya

2013-04-30T23:59:59.000Z

53

QCD Phase Transitions, Volume 15  

SciTech Connect

The title of the workshop, ''The QCD Phase Transitions'', in fact happened to be too narrow for its real contents. It would be more accurate to say that it was devoted to different phases of QCD and QCD-related gauge theories, with strong emphasis on discussion of the underlying non-perturbative mechanisms which manifest themselves as all those phases. Before we go to specifics, let us emphasize one important aspect of the present status of non-perturbative Quantum Field Theory in general. It remains true that its studies do not get attention proportional to the intellectual challenge they deserve, and that the theorists working on it remain very fragmented. The efforts to create Theory of Everything including Quantum Gravity have attracted the lion share of attention and young talent. Nevertheless, in the last few years there was also a tremendous progress and even some shift of attention toward emphasis on the unity of non-perturbative phenomena. For example, we have seen some efforts to connect the lessons from recent progress in Supersymmetric theories with that in QCD, as derived from phenomenology and lattice. Another example is Maldacena conjecture and related development, which connect three things together, string theory, super-gravity and the (N=4) supersymmetric gauge theory. Although the progress mentioned is remarkable by itself, if we would listen to each other more we may have chance to strengthen the field and reach better understanding of the spectacular non-perturbative physics.

Schaefer, T.; Shuryak, E.

1999-03-20T23:59:59.000Z

54

Excited light isoscalar mesons from lattice QCD  

Science Conference Proceedings (OSTI)

I report a recent lattice QCD calculation of an excited spectrum of light isoscalar mesons, something that has up to now proved challenging for lattice QCD. With novel techniques we extract an extensive spectrum with high statistical precision, including spin-four states and, for the first time, light isoscalars with exotic quantum numbers. In addition, the hidden flavour content of these mesons is determined, providing a window on annihilation dynamics in QCD. I comment on future prospects including applications to the study of resonances.

Christopher Thomas

2011-07-01T23:59:59.000Z

55

Nuclear forces from lattice QCD  

SciTech Connect

Lattice QCD construction of nuclear forces is reviewed. In this method, the nuclear potentials are constructed by solving the Schroedinger equation, where equal-time Nambu-Bethe-Salpeter (NBS) wave functions are regarded as quantum mechanical wave functions. Since the long distance behavior of equal-time NBS wave functions is controlled by the scattering phase, which is in exactly the same way as scattering wave functions in quantum mechanics, the resulting potentials are faithful to the NN scattering data. The derivative expansion of this potential leads to the central and the tensor potentials at the leading order. Some of numerical results of these two potentials are shown based on the quenched QCD.

Ishii, Noriyoshi [Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)

2011-05-06T23:59:59.000Z

56

--No Title--  

NLE Websites -- All DOE Office Websites (Extended Search)

of Quantum Chromodynamics (QCD), has been and still is at the frontier of high energy nuclear physics research. Concurrent advances in the experimental use of high energy...

57

Theoretical Physics continued | U.S. DOE Office of Science (SC...  

Office of Science (SC) Website

analyzing data from the LHC to identify which of these many ideas are true. Lattice Quantum Chromodynamics (QCD) is one very successful theory. It describes strong interactions...

58

QCD Thermodynamics  

E-Print Network (OSTI)

Recent results on QCD thermodynamics are presented. The nature of the T>0 transition is determined, which turns out to be an analytic cross-over. The absolute scale for this transition is calculated. The temperature dependent static potential is given. The results were obtained by using a Symanzik improved gauge and stout-link improved fermionic action. In order to approach the continuum limit four different sets of lattice spacings were used with temporal extensions N_t=4, 6, 8 and 10 (they correspond to lattice spacings a \\sim 0.3, 0.2, 0.15 and 0.12 fm). A new technique is presented, which --in contrast to earlier methods-- enables one to determine the equation of state at very large temperatures.

Z. Fodor

2007-11-02T23:59:59.000Z

59

Proceedings of RIKEN BNL Research Center Workshop entitled Hydrodynamics in Heavy Ion Collisions and QCD Equation of State (Volume 88)  

SciTech Connect

The interpretation of relativistic heavy-ion collisions at RHIC energies with thermal concepts is largely based on the relative success of ideal (nondissipative) hydrodynamics. This approach can describe basic observables at RHIC, such as particle spectra and momentum anisotropies, fairly well. On the other hand, recent theoretical efforts indicate that dissipation can play a significant role. Ideally viscous hydrodynamic simulations would extract, if not only the equation of state, but also transport coefficients from RHIC data. There has been a lot of progress with solving relativistic viscous hydrodynamics. There are already large uncertainties in ideal hydrodynamics calculations, e.g., uncertainties associated with initial conditions, freezeout, and the simplified equations of state typically utilized. One of the most sensitive observables to the equation of state is the baryon momentum anisotropy, which is also affected by freezeout assumptions. Up-to-date results from lattice quantum chromodynamics on the transition temperature and equation of state with realistic quark masses are currently available. However, these have not yet been incorporated into the hydrodynamic calculations. Therefore, the RBRC workshop 'Hydrodynamics in Heavy Ion Collisions and QCD Equation of State' aimed at getting a better understanding of the theoretical frameworks for dissipation and near-equilibrium dynamics in heavy-ion collisions. The topics discussed during the workshop included techniques to solve the dynamical equations and examine the role of initial conditions and decoupling, as well as the role of the equation of state and transport coefficients in current simulations.

Karsch,F.; Kharzeev, D.; Molnar, K.; Petreczky, P.; Teaney, D.

2008-04-21T23:59:59.000Z

60

Review on the determination of alpha_s from the QCD static energy  

E-Print Network (OSTI)

We review the determination of the strong coupling alpha_s from the comparison of the perturbative expression for the Quantum Chromodynamics static energy with lattice data. We collect here all the perturbative expressions needed to evaluate the static energy at the currently known accuracy.

Tormo, Xavier Garcia i

2013-01-01T23:59:59.000Z

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


61

Nuclear Physics from QCD  

E-Print Network (OSTI)

Effective field theories provide a bridge between QCD and nuclear physics. I discuss light nuclei from this perspective, emphasizing the role of fine-tuning.

U. van Kolck

2008-12-20T23:59:59.000Z

62

QCD results at CDF  

SciTech Connect

Recent QCD measurements from the CDF collaboration at the Tevatron are presented, together with future prospects as the luminosity increases. The measured inclusive jet cross section is compared to pQCD NLO predictions. Precise measurements on jet shapes and hadronic energy flows are compared to different phenomenological models that describe gluon emissions and the underlying event in hadron-hadron interactions.

Norniella, Olga; /Barcelona, IFAE

2005-01-01T23:59:59.000Z

63

Fluctuations and the QCD phase diagram  

SciTech Connect

In this contribution the role of quantum fluctuations for the QCD phase diagram is discussed. This concerns in particular the importance of the matter back-reaction to the gluonic sector. The impact of these fluctuations on the location of the confinement/deconfinement and the chiral transition lines as well as their interrelation are investigated. Consequences of our findings for the size of a possible quarkyonic phase and location of a critical endpoint in the phase diagram are drawn.

Schaefer, B.-J., E-mail: bernd-jochen.schaefer@uni-graz.at [Karl-Franzens-Universitaet, Institut fuer Physik (Austria)

2012-06-15T23:59:59.000Z

64

Computers for Lattice QCD  

E-Print Network (OSTI)

The architecture and capabilities of the computers currently in use for large-scale lattice QCD calculations are described and compared. Based on this present experience, possible future directions are discussed.

Norman H. Christ

1999-12-06T23:59:59.000Z

65

quarkmodrpp.dvi  

NLE Websites -- All DOE Office Websites (Extended Search)

DeGrand (University of Colorado, Boulder), and B. Krusche (University of Basel). 14.1. Quantum numbers of the quarks Quantum chromodynamics (QCD) is the theory of the strong...

66

Yang-Mills Propagators and QCD  

E-Print Network (OSTI)

We present a strong coupling expansion that permits to develop analysis of quantum field theory in the infrared limit. Application to a quartic massless scalar field gives a massive spectrum and the propagator in this regime. We extend the approach to a pure Yang-Mills theory obtaining analogous results. The gluon propagator is compared satisfactorily with lattice results and similarly for the spectrum. Comparison with experimental low energy spectrum of QCD supports the view that $\\sigma$ resonance is indeed a glueball. The gluon propagator we obtained is finally used to formulate a low energy Lagrangian for QCD that reduces to a Nambu-Jona-Lasinio model with all the parameters fixed by those of the full theory.

Marco Frasca

2008-07-27T23:59:59.000Z

67

Lattice QCD for Small Computers  

E-Print Network (OSTI)

These lectures discuss field theoretic techniques that might allow for realistic simulations of lattice QCD on small computers.

G. P. Lepage

1994-03-16T23:59:59.000Z

68

Novel QCD Phenomena  

SciTech Connect

I discuss a number of novel topics in QCD, including the use of the AdS/CFT correspondence between Anti-de Sitter space and conformal gauge theories to obtain an analytically tractable approximation to QCD in the regime where the QCD coupling is large and constant. In particular, there is an exact correspondence between the fifth-dimension coordinate z of AdS space and a specific impact variable {zeta} which measures the separation of the quark constituents within the hadron in ordinary space-time. This connection allows one to compute the analytic form of the frame-independent light-front wavefunctions of mesons and baryons, the fundamental entities which encode hadron properties and allow the computation of exclusive scattering amplitudes. I also discuss a number of novel phenomenological features of QCD. Initial- and final-state interactions from gluon-exchange, normally neglected in the parton model, have a profound effect in QCD hard-scattering reactions, leading to leading-twist single-spin asymmetries, diffractive deep inelastic scattering, diffractive hard hadronic reactions, the breakdown of the Lam Tung relation in Drell-Yan reactions, and nuclear shadowing and non-universal antishadowing--leading-twist physics not incorporated in the light-front wavefunctions of the target computed in isolation. I also discuss tests of hidden color in nuclear wavefunctions, the use of diffraction to materialize the Fock states of a hadronic projectile and test QCD color transparency, and anomalous heavy quark effects. The presence of direct higher-twist processes where a proton is produced in the hard subprocess can explain the large proton-to-pion ratio seen in high centrality heavy ion collisions.

Brodsky, Stanley J.; /SLAC

2007-07-06T23:59:59.000Z

69

Two novel methods in QCD sum rules  

SciTech Connect

Two novel methods in extracting the spectral information of hadrons in the QCD sum rule technique. The first one is to combine two sum rules so that the pole dominance is achieved and the resonance information is effectively obtained. This method is applied to the pentaquark {Theta}{sup +} and its quantum numbers are predicted. The second method is to use the Bayesian inference theory to obtain the most probable form of the spectral function from the sum rule. We have checked the method to work in the case of the rho meson sum rule.

Gubler, Philipp; Oka, Makoto [Dept. of Physics, H-27, Tokyo Institute of Technology, Meguro, Tokyo 152-8551 (Japan)

2010-12-28T23:59:59.000Z

70

Electromagnetic polarizabilities: Lattice QCD in background fields  

Science Conference Proceedings (OSTI)

Chiral perturbation theory makes definitive predictions for the extrinsic behavior of hadrons in external electric and magnetic fields. Near the chiral limit, the electric and magnetic polarizabilities of pions, kaons, and nucleons are determined in terms of a few well-known parameters. In this limit, hadrons become quantum mechanically diffuse as polarizabilities scale with the inverse square-root of the quark mass. In some cases, however, such predictions from chiral perturbation theory have not compared well with experimental data. Ultimately we must turn to first principles numerical simulations of QCD to determine properties of hadrons, and confront the predictions of chiral perturbation theory. To address the electromagnetic polarizabilities, we utilize the background field technique. Restricting our attention to calculations in background electric fields, we demonstrate new techniques to determine electric polarizabilities and baryon magnetic moments for both charged and neutral states. As we can study the quark mass dependence of observables with lattice QCD, the lattice will provide a crucial test of our understanding of low-energy QCD, which will be timely in light of ongoing experiments, such as at COMPASS and HI gamma S.

W. Detmold, B.C. Tiburzi, A. Walker-Loud

2012-04-01T23:59:59.000Z

71

Thermodynamics of 1-flavor QCD  

E-Print Network (OSTI)

We present first results, for heavy to moderate quark masses, of a study of thermodynamic properties of 1-flavor QCD, using the multiboson algorithm.

C. Alexandrou; A. Boriçi; A. Feo; Ph. de Forcrand; A. Galli; F. Jegerlehner; T. Takaishi

1996-09-18T23:59:59.000Z

72

Light-Front Holographic QCD and the Confinement Potential  

E-Print Network (OSTI)

Light-Front Hamiltonian theory, derived from the quantization of the QCD Lagrangian at fixed light-front time \\tau = t+z/c, provides a rigorous frame-independent framework for solving nonperturbative QCD. The eigenvalues of the light-front QCD Hamiltonian predict the hadronic mass spectrum, and the eigensolutions provide the light-front wavefunctions describing hadron structure. The valence Fock-state wavefunctions of the light-front QCD Hamiltonian satisfy a single-variable relativistic equation of motion, analogous to the nonrelativistic radial Schrodinger equation, with an effective confining potential U which systematically incorporates the effects of higher quark and gluon Fock states. The potential U has a unique form if one requires that the action for zero quark mass remains conformally invariant. The holographic mapping of gravity in AdS space to QCD with a specific soft-wall dilaton yields the same light-front Schrodinger equation. It also gives a precise relation between the bound-state amplitudes in the fifth dimension z of AdS space and the boost-invariant light-front wavefunctions describing the internal structure of hadrons in physical space-time. The elastic and transition form factors of the pion and the nucleons are found to be well described in this framework. The predictions include a zero-mass pion in the chiral limit, and linear Regge trajectories with the same slope in the radial quantum number n and orbital angular momentum L. The light-front AdS/QCD holographic approach thus gives a frame-independent representation of color-confining dynamics and the excitation spectra of light-quark hadrons in terms of a single mass parameter. We also discuss the implications of the underlying conformal template of QCD for renormalization scale-setting and the implications of light-front quantization for the value of the cosmological constant.

Stanley J. Brodsky; Guy F. de Téramond; Hans Günter Dosch

2013-08-23T23:59:59.000Z

73

Jet quenching in heavy-ion collisions at LHC with CMS detector  

E-Print Network (OSTI)

The collision of highly relativistic nuclei can produce a volume of high energy density which can be used to learn about the behavior of quantum chromodynamics (QCD) at extreme conditions, such as those of the universe at ...

Yilmaz, Yetkin

2013-01-01T23:59:59.000Z

74

Equilibrium Thermodynamics of Lattice QCD  

E-Print Network (OSTI)

Lattice QCD allows us to simulate QCD at non-zero temperature and/or densities. Such equilibrium thermodynamics calculations are relevant to the physics of relativistic heavy-ion collisions. I give a brief review of the field with emphasis on our work.

D. K. Sinclair

2007-01-14T23:59:59.000Z

75

QCDOC -Quantum Chromodynamics on a Chip at BNL | U.S. DOE Office...  

Office of Science (SC) Website

for Teachers and Scientists Small Business Innovation Research and Small Business Technology Transfer Project Assessment Laboratories Ames Laboratory Argonne National...

76

Nonlocal Condensates in QCD  

E-Print Network (OSTI)

In the presence of the nontrivial QCD ground state or vacuum, nonlocal condensates are used to characterize the quark or gluon propagator, or other Green functions of higher order. In this paper, we wish to show that, by taking the large $N_c$ limit (with $N_c$ the number of color) in treating higher-order condensates, a closed set of coupled differential equations may be derived for nonlocal condensates. As a specific example, the leading-order equations for the nonlocal condensates appearing in the quark propagator are derived and explicit solutions are obtained. Some applications of our analytical results are briefly discussed.

W-Y. P. Hwang

1997-02-03T23:59:59.000Z

77

Manifestly Gauge Invariant QCD  

E-Print Network (OSTI)

Building on recent work in SU(N) Yang-Mills theory, we construct a manifestly gauge invariant exact renormalization group for QCD. A gauge invariant cutoff is constructed by embedding the physical gauge theory in a spontaneously broken SU(N|N) gauge theory, regularized by covariant higher derivatives. Intriguingly, the construction is most efficient if the number of flavours is a multiple of the number of colours. The formalism is illustrated with a very compact calculation of the one-loop beta function, achieving a manifestly universal result and without fixing the gauge.

Tim R. Morris; Oliver J. Rosten

2006-06-20T23:59:59.000Z

78

New Perspectives for QCD Physics at the LHC  

SciTech Connect

I review a number of topics where conventional wisdom relevant to hadron physics at the LHC has been challenged. For example, the initial-state and final-state interactions of the quarks and gluons entering perturbative QCD hard-scattering subprocesses lead to the breakdown of traditional concepts of factorization and universality for transverse-momentum-dependent observables at leading twist. These soft-gluon rescattering effect produce single-spin asymmetries, the breakdown of the Lam-Tung relation in Drell-Yan reactions, as well as diffractive deep inelastic scattering, The antishadowing of nuclear structure functions is predicted to depend on the flavor quantum numbers of each quark and antiquark. Isolated hadrons can be produced at large transverse momentum directly within a hard higher-twist QCD subprocess, rather than from jet fragmentation, even at the LHC. Such 'direct' processes can explain the observed deviations from pQCD predictions of the power-law fall-off of inclusive hadron cross sections as well as the 'baryon anomaly' seen in high-centrality heavy-ion collisions at RHIC. The intrinsic charm contribution to the proton structure function at high x can explain the large rate for high p{sub T} photon plus charm-jet events observed at the Tevatron and imply a large production rate for charm and bottom jets at high p{sub T} at the LHC, as well as a novel mechanism for Higgs and Z{sup 0} production at high x{sub F}. The light-front wavefunctions derived in AdS/QCD can be used to calculate jet hadronization at the amplitude level. The elimination of the renormalization scale ambiguity for the QCD coupling using the scheme-independent BLM method will increase the sensitivity of searches for new physics at the LHC. The implications of 'in-hadron condensates' for the QCD contribution to the cosmological constant are also discussed.

Brodsky, Stanley J.; /SLAC /Stanford U. /Southern Denmark U., CP3-Origins

2011-02-07T23:59:59.000Z

79

Hot and Dense QCD Matter  

NLE Websites -- All DOE Office Websites (Extended Search)

QCD Matter QCD Matter A Community White Paper on the Future of Relativistic Heavy-Ion Physics in the US Unraveling the Mysteries of the Strongly Interacting Quark-Gluon-Plasma Executive Summary This document presents the response of the US relativistic heavy-ion community to the request for comments by the NSAC Subcommittee, chaired by Robert Tribble, that is tasked to recommend optimizations to the US Nuclear Science Program over the next five years. The study of the properties of hot and dense QCD matter is one of the four main areas of nuclear physics research described in the 2007 NSAC Long Range Plan. The US nuclear physics community plays a leading role in this research area and has been instrumental in its most important discovery made over the past decade, namely that hot and dense QCD matter acts as a strongly interacting system with unique and previously unexpected

80

Lattice QCD and NERSC requirements  

NLE Websites -- All DOE Office Websites (Extended Search)

Doug Toussaint November 26, 2012 Rich Brower, Steven Gottlieb and Doug Toussaint () Lattice QCD at NERSC November 26, 2012 1 17 Lattice Gauge Theory at NERSC First-principles...

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


81

Dyson-Schwinger Equations: Density, Temperature and Continuum Strong QCD  

E-Print Network (OSTI)

Continuum strong QCD is the application of models and continuum quantum field theory to the study of phenomena in hadronic physics, which includes; e.g., the spectrum of QCD bound states and their interactions; and the transition to, and properties of, a quark gluon plasma. We provide a contemporary perspective, couched primarily in terms of the Dyson-Schwinger equations but also making comparisons with other approaches and models. Our discourse provides a practitioners' guide to features of the Dyson-Schwinger equations [such as confinement and dynamical chiral symmetry breaking] and canvasses phenomenological applications to light meson and baryon properties in cold, sparse QCD. These provide the foundation for an extension to hot, dense QCD, which is probed via the introduction of the intensive thermodynamic variables: chemical potential and temperature. We describe order parameters whose evolution signals deconfinement and chiral symmetry restoration, and chronicle their use in demarcating the quark gluon plasma phase boundary and characterising the plasma's properties. Hadron traits change in an equilibrated plasma. We exemplify this and discuss putative signals of the effects. Finally, since plasma formation is not an equilibrium process, we discuss recent developments in kinetic theory and its application to describing the evolution from a relativistic heavy ion collision to an equilibrated quark gluon plasma.

C. D. Roberts; S. M. Schmidt

2000-05-24T23:59:59.000Z

82

POLYNOMIAL CHROMODYNAMICS  

E-Print Network (OSTI)

Physics of the Office of High Energy and Nuclear Physics ofPhysics of the Office of High Energy and Nuclear Physics ofthe Director, Office of Energy Research, Division of Nuclear

Ruck, H.M.

2010-01-01T23:59:59.000Z

83

QCD Thermodynamics on the Lattice: Recent Results  

E-Print Network (OSTI)

I give a brief introduction to the goals, challenges, and technical difficulties of lattice QCD thermodynamics and present some recent results from the HotQCD collaboration for the crossover temperature, equation of state, and other observables.

Carleton DeTar

2010-12-31T23:59:59.000Z

84

Radiative QCD corrections a personal outlook  

E-Print Network (OSTI)

We describe several problems related to the studies of the effects of radiative QCD corrections in the phenomenological and theoretical considerations thus summarizing the work of the QCD part of the Symposium on "Radiative Corrections: Status and Outlook".

Kataev, A L

1994-01-01T23:59:59.000Z

85

Radiative QCD Corrections: A Personal Outlook  

E-Print Network (OSTI)

We describe several problems related to the studies of the effects of radiative QCD corrections in the phenomenological and theoretical considerations thus summarizing the work of the QCD part of the Symposium on "Radiative Corrections: Status and Outlook".

Andrei L. Kataev

1994-10-18T23:59:59.000Z

86

QCD Phase Diagram with Imaginary Chemical Potential  

E-Print Network (OSTI)

We report our recent results on the QCD phase diagram obtained from the lattice QCD simulation. The location of the phase boundary between hadronic and QGP phases in the two-flavor QCD phase diagram is investigated. The imaginary chemical potential approach is employed, which is based on Monte Carlo simulations of the QCD with imaginary chemical potential and analytic continuation to the real chemical potential region.

Nagata, Keitaro

2011-01-01T23:59:59.000Z

87

Lattice QCD thermodynamics with Wilson quarks  

E-Print Network (OSTI)

We review studies of QCD thermodynamics by lattice QCD simulations with dynamical Wilson quarks. After explaining the basic properties of QCD with Wilson quarks at finite temperature including the phase structure and the scaling properties around the chiral phase transition, we discuss the critical temperature, the equation of state and heavy-quark free energies.

Shinji Ejiri

2007-04-27T23:59:59.000Z

88

LATTICE QCD THERMODYNAMICS WITH WILSON QUARKS.  

SciTech Connect

We review studies of QCD thermodynamics by lattice QCD simulations with dynamical Wilson quarks. After explaining the basic properties of QCD with Wilson quarks at finite temperature including the phase structure and the scaling properties around the chiral phase transition, we discuss the critical temperature, the equation of state and heavy-quark free energies.

EJIRI,S.

2007-11-20T23:59:59.000Z

89

Hadron Structure from Lattice QCD  

NLE Websites -- All DOE Office Websites (Extended Search)

Lattice QCD in Nuclear Physics Lattice QCD in Nuclear Physics Robert Edwards Jefferson Lab NERSC 2011 Report: Robert Edwards, Martin Savage & Chip Watson Current HPC Methods * Algorithms - Gauge generation - Analysis phase * Codes - USQCD SciDAC codes - Heavily used at NERSC: QDP++ & Chroma * Quantities that affect the scale of the simulations - Lattice size, lattice spacing & pion mass Gauge generation Hybrid Monte Carlo (HMC) * Hamiltonian integrator: 1 st order coupled PDE's * Large, sparse, matrix solve per step * "Configurations" via importance sampling * Use Metropolis method * Produce ~1000 useful configurations in a dataset Cost: * Controlled by lattice size & spacing, quark mass * Requires capability resources

90

Twistor inspired techniques in QCD  

Science Conference Proceedings (OSTI)

I present a short review of the new twistor inspired techniques in perturbative QCD, which are the result of Witten's conjecture of a duality between twistors and string theory. I give an introduction to the main two tree-level techniques, the BCFW recursion and the CSW formalism, and show how the idea of using on-shell QCD amplitudes evaluated for complex momenta can lead to efficient techniques to perform analytic computations. Finally, I briefly discuss how these ideas can be applied to loop calculations if they are combined to the generalized unitarity approach.

Duhr, C. [Center for Particle Physics and Phenomenology (CP3), Universite catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium)

2008-08-29T23:59:59.000Z

91

Extremal black disks in QCD  

E-Print Network (OSTI)

We argue that in the high energy QCD a true black disk wave function necessarily contains many quarks. This corresponds to necessity of non-vacuum reggeon loops in formation of a black disk. The result comes from decomposition of the black disk S-matrix in characters on group manifold.

Alexey V. Popov

2008-05-12T23:59:59.000Z

92

Group theoretical construction of extended baryon operators in lattice QCD  

SciTech Connect

The design and implementation of large sets of spatially-extended, gauge-invariant operators for use in determining the spectrum of baryons in lattice QCD computations are described. Group theoretical projections onto the irreducible representations of the symmetry group of a cubic spatial lattice are used in all isospin channels. The operators are constructed to maximize overlaps with the low-lying states of interest, while minimizing the number of sources needed in computing the required quark propagators. Issues related to the identification of the spin quantum numbers of the states in the continuum limit are addressed.

Subhasish Basak; Robert Edwards; George Fleming; Urs Heller; Colin Morningstar; David Richards; Ikuro Sato; Stephen Wallace

2005-06-01T23:59:59.000Z

93

Rotor Spectra, Berry Phases, and Monopole Fields: from Antiferromagnets to QCD  

E-Print Network (OSTI)

The order parameter of a finite system with a spontaneously broken continuous global symmetry acts as a quantum mechanical rotor. Both antiferromagnets with a spontaneously broken $SU(2)_s$ spin symmetry and massless QCD with a broken $SU(2)_L \\times SU(2)_R$ chiral symmetry have rotor spectra when considered in a finite volume. When an electron or hole is doped into an antiferromagnet or when a nucleon is propagating through the QCD vacuum, a Berry phase arises from a monopole field and the angular momentum of the rotor is quantized in half-integer units.

S. Chandrasekharan; F. -J. Jiang; M. Pepe; U. -J. Wiese

2006-12-11T23:59:59.000Z

94

Colour transparency: a novel test of QCD in nuclear interactions  

E-Print Network (OSTI)

Colour transparency is a cute and indispensable property of QCD as the gauge theory of strong interaction. CT tests of QCD consist of production of the perturbative small-sized hadronic state and measuring the strngth of its non-perturbative diffraction nteraction in a nuclear matter. The energy depenednce of the final- state interaction in a nuclear matter probes a dynamical evolution from the perturbative small-sized state to the full-sized nonperturbative hadron. QCD observables of CT experiments correspond to a novel mechanism of scanning of hadronic wave functions from the large nonperturbative to the small perturbative size. In these lectures, which are addressed to experimentalists and theorists, I discuss the principle ideas of CT physics and the physics potential of the hadron and electron facilities in the > 10 GeV energy range. The special effort was made to present the material in the pedagigical and self-consistent way, with an emphasis on the underlying rich quantum-mechanical interference phenomena.

N. N. Nikolaev

1993-04-20T23:59:59.000Z

95

Form factors from lattice QCD  

Science Conference Proceedings (OSTI)

Precision computation of hadronic physics with lattice QCD is becoming feasible. The last decade has seen precent-level calculations of many simple properties of mesons, and the last few years have seen calculations of baryon masses, including the nucleon mass, accurate to a few percent. As computational power increases and algorithms advance, the precise calculation of a variety of more demanding hadronic properties will become realistic. With this in mind, I discuss the current lattice QCD calculations of generalized parton distributions with an emphasis on the prospects for well-controlled calculations for these observables as well. I will do this by way of several examples: the pion and nucleon form factors and moments of the nucleon parton and generalized-parton distributions.

Dru Renner

2012-04-01T23:59:59.000Z

96

LatticeQCD - Early Science | Argonne Leadership Computing Facility  

NLE Websites -- All DOE Office Websites (Extended Search)

summary of Lattice QCD averages The current summary of Lattice QCD averages. Laiho, Lunghi, & Van de Water, Phys.Rev.D81:034503,2010. LatticeQCD - Early Science PI Name: Paul...

97

Latest QCD results from LEP  

E-Print Network (OSTI)

We summarise the latest experimental QCD studies based on data from LEP. Measurements of the quark and gluon jet fragmentation functions are discussed, including a new algorithm to infer the properties of unbiased gluon jets. We describe a new test for destructive interference in the radiation of soft gluons from a three-parton system. Finally, we report the latest combined value of the strong coupling, measured using event shape observables.

Matthew Ford

2004-06-03T23:59:59.000Z

98

Signatures of confinement in axial gauge QCD  

SciTech Connect

A comparative dynamical study of axial gauge QED and QCD is presented. Elementary excitations associated with particular field configurations are investigated. Gluonic excitations analogous to linearly polarized photons are shown to acquire infinite energy. Suppression of this class of excitations in QCD results from quantization of the chromo-electric flux and is interpreted as a dual Meissner effect, i.e., as expulsion from the QCD vacuum of chromo-electric fields which are constant over significant distances. This interpretation is supported by a comparative evaluation of the interaction energy of static charges in the axial gauge representation of QED and QCD. {copyright} 1995 Academic Press, Inc.

Lenz, F. [Institute for Theoretical Physics, University of Erlangen-Nuernberg, Staudtstrasse 7, 91058 Erlangen (Germany)]|[Center for Theoretical Physics, Laboratory for Nuclear Science, MIT, Cambridge, Massachusetts 02139 (United States); Moniz, E.J. [Center for Theoretical Physics, Laboratory for Nuclear Science, MIT, Cambridge, Massachusetts 02139 (United States)]|[Institute for Theoretical Physics, University of Erlangen-Nuernberg, Staudtstrasse 7, 91058 Erlangen (Germany); Thies, M. [Institute for Theoretical Physics, University of Erlangen-Nuernberg, Staudtstrasse 7, 91058 Erlangen (Germany)

1995-09-01T23:59:59.000Z

99

QCDOC: A 10 Teraflops Computer for Tightly-Coupled Calculations  

Science Conference Proceedings (OSTI)

Numerical simulations of the strong nuclear force, known as quantum chromodynamics or QCD, have proven to be a demanding, forefront problem in high-performance computing. In this report, we describe a new computer, QCDOC (QCD On a Chip), designed for ...

P. A. Boyle; Dong Chen; Norman H. Christ; Mike Clark; Saul Cohen; Zhihua Dong; Alan Gara; Balint Joo; Chulwoo Jung; Ludmila Levkova; Xiaodong Liao; Guofeng Liu; Robert D. Mawhinney; Shigemi Ohta; Konstantin Petrov; Tilo Wettig; Azusa Yamaguchi; Calin Cristian

2004-11-01T23:59:59.000Z

100

Lattice QCD and High Baryon Density State  

SciTech Connect

We report our recent studies on the finite density QCD obtained from lattice QCD simulation with clover-improved Wilson fermions of two flavor and RG-improved gauge action. We approach the subject from two paths, i.e., the imaginary and chemical potentials.

Nagata, Keitaro [Department of Physics, University of Tokyo, Bunkyo-ku, Tokyo 113-0033 (Japan); Research Institute for Information Science and Education, Hiroshima University, Higashi-Hiroshima 739-8527 (Japan); Nakamura, Atsushi; Motoki, Shinji [Research Institute for Information Science and Education, Hiroshima University, Higashi-Hiroshima 739-8527 (Japan); Nakagawa, Yoshiyuki [Graduate School of Science and Technology, Niigata University, Niigata 950-2181 (Japan); Saito, Takuya [Integrated Information Center, Kochi University, Kochi, 780-8520 (Japan)

2011-10-21T23:59:59.000Z

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


101

Tetraquark states from lattice QCD  

Science Conference Proceedings (OSTI)

Recently there have been considerable interests in studying hadronic states beyond the usual two and three quark configurations. With the renewed experimental interests in {sigma}(600) and the inability of quark model to incorporate too many light scalar mesons, it is quite appropriate to study hadronic states with four quark configurations. Moreover, some of the newly observed charmed hadrons may well be described by four quark configurations. Lattice QCD is perhaps the most desirable tool to adjudicate the theoretical controversy of the scalar mesons and to interpret the structures of the newly observed charmed states. Here we briefly reviewed the lattice studies of four-quark hadrons.

Mathur, Nilmani [Department of Theoretical Physics, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005 (India)

2011-10-24T23:59:59.000Z

102

In the debris of hadron interactions lies the beauty of QCD (part II)  

E-Print Network (OSTI)

Recent progress in understanding the strong physics regime of QCD is described. The role played by condensates, particularly $$, in breaking chiral symmetry and generating constituent masses for $u$ and $d$ quarks is reviewed. The influence this has on hadrons with vacuum quantum numbers is emphasised. What we know of this sector from recent experiments on $\\phi$-radiative decays and from $D$ decays to light hadrons is discussed. How we may gain a more complete understanding of this vacuum sector is outlined.

M. R. Pennington

2003-10-15T23:59:59.000Z

103

Nuclear Force from Lattice QCD  

E-Print Network (OSTI)

The first lattice QCD result on the nuclear force (the NN potential) is presented in the quenched level. The standard Wilson gauge action and the standard Wilson quark action are employed on the lattice of the size 16^3\\times 24 with the gauge coupling beta=5.7 and the hopping parameter kappa=0.1665. To obtain the NN potential, we adopt a method recently proposed by CP-PACS collaboration to study the pi pi scattering phase shift. It turns out that this method provides the NN potentials which are faithful to those obtained in the analysis of NN scattering data. By identifying the equal-time Bethe-Salpeter wave function with the Schroedinger wave function for the two nucleon system, the NN potential is reconstructed so that the wave function satisfies the time-independent Schroedinger equation. In this report, we restrict ourselves to the J^P=0^+ and I=1 channel, which enables us to pick up unambiguously the ``central'' NN potential V_{central}(r). The resulting potential is seen to posses a clear repulsive core of about 500 MeV at short distance (r < 0.5 fm). Although the attraction in the intermediate and long distance regions is still missing in the present lattice set-up, our method is appeared to be quite promising in reconstructing the NN potential with lattice QCD.

Noriyoshi ISHII; Sinya AOKI; Tetsuo HATSUDA

2006-09-30T23:59:59.000Z

104

AdS/QCD at finite density and temperature  

Science Conference Proceedings (OSTI)

We review some basics of AdS/QCD following a non-standard path and list a few results from AdS/QCD or holographic QCD. The non-standard path here is to use the analogy of the way one obtains an effective model of QCD like linear sigma model and the procedure to construct an AdS/QCD model based on the AdS/CFT dictionary.

Kim, Y., E-mail: ykim@apctp.org [Pohang University of Science and Technology, Asia Pacific Center for Theoretical Physics and Department of Physics (Korea, Republic of)

2012-07-15T23:59:59.000Z

105

16th International Conference in Quantum ChromoDynamics: Charmonium-like states at BaBar  

E-Print Network (OSTI)

We present new results on charmonium-like states from the BaBar experiment located at the PEP-II asymmetric energy $e^+e^-$ collider at the SLAC National Accelerator Laboratory.

Elisa Fioravanti

2013-09-17T23:59:59.000Z

106

The Massive Pulsar PSR J1614-2230: Linking Quantum Chromodynamics, Gamma-ray Bursts, and Gravitational Wave Astronomy  

E-Print Network (OSTI)

The recent measurement of the Shapiro delay in the radio pulsar PSR J1614-2230 yielded a mass of 1.97 +/- 0.04 M_sun, making it the most massive pulsar known to date. Its mass is high enough that, even without an accompanying measurement of the stellar radius, it has a strong impact on our understanding of nuclear matter, gamma-ray bursts, and the generation of gravitational waves from coalescing neutron stars. This single high mass value indicates that a transition to quark matter in neutron-star cores can occur at densities comparable to the nuclear saturation density only if the quarks are strongly interacting and are color superconducting. We further show that a high maximum neutron-star mass is required if short duration gamma-ray bursts are powered by coalescing neutron stars and, therefore, this mechanism becomes viable in the light of the recent measurement. Finally, we argue that the low-frequency (<= 500 Hz) gravitational waves emitted during the final stages of neutron-star coalescence encode the properties of the equation of state because neutron stars consistent with this measurement cannot be centrally condensed. This will facilitate the measurement of the neutron star equation of state with Advanced LIGO/Virgo.

Feryal Ozel; Dimitrios Psaltis; Scott Ransom; Paul Demorest; Mark Alford

2010-10-27T23:59:59.000Z

107

Recent Progress in Lattice QCD Thermodynamics  

E-Print Network (OSTI)

This review gives a critical assessment of the current state of lattice simulations of QCD thermodynamics and what it teaches us about hot hadronic matter. It outlines briefly lattice methods for studying QCD at nonzero temperature and zero baryon number density with particular emphasis on assessing and reducing cutoff effects. It discusses a variety of difficulties with methods for determining the transition temperature. It uses results reported recently in the literature and at this conference for illustration, especially those from a major study carried out by the HotQCD collaboration.

Carleton DeTar

2008-11-14T23:59:59.000Z

108

Hadron Mass Extraction from Lattice QCD  

E-Print Network (OSTI)

The extraction of quantities from lattice QCD calculations at realistic quark masses is of considerable importance. Whilst physical quark masses are some way off, the recent advances in the calculation of hadron masses within full QCD now invite improved extrapolation methods. We show that, provided the correct chiral behaviour of QCD is respected in the extrapolation to realistic quark masses, one can indeed obtain a fairly reliable determination of masses, the sigma commutator and the J parameter. We summarise these findings by presenting the nonanalytic behaviour of nucleon and rho masses in the standard Edinburgh plot.

S. V. Wright; D. B. Leinweber; A. W. Thomas; K. Tsushima

2001-11-27T23:59:59.000Z

109

Quantum Computation Quantum Information  

E-Print Network (OSTI)

Quantum Computation and Quantum Information Samuel J. Lomonaco, Jr. and Howard E. Brandt editors Searches with a Quantum Robot .............................................. 12 pages Benioff, Paul Perturbation Theory and Numerical Modeling Quantum Logic Operations with a Large of Qubits

Lomonaco Jr., Samuel J.

110

Lattice QCD and String Theory  

E-Print Network (OSTI)

Bosonic string formation in gauge theories is reviewed with particular attention to the confining flux in lattice QCD and its string theory description. Recent results on the Casimir energy of the ground state and the string excitation spectrum are analyzed in the Dirichlet string limit of large separation between static sources. The closed string-soliton (torelon) with electric flux winding around a compact dimension and the three-string with a Y-junction created by three static sources are also reviewed. It is shown that string spectra from lattice simulations are consistent with universal predictions of the leading operators from the derivative expansion of a Poincare invariant effective string Lagrangian with reparameterization symmetry. Important characterisitics of the confining flux, like stiffness and the related massive breather modes, are coded in operators with higher derivatives and their determination remains a difficult challenge for lattice gauge theory.

Julius Kuti

2005-11-08T23:59:59.000Z

111

Nuclear force in Lattice QCD  

E-Print Network (OSTI)

We perform the quenched lattice QCD analysis on the nuclear force (baryon-baryon interactions). We employ $20^3\\times 24$ lattice at $\\beta=5.7$ ($a\\simeq 0.19$ fm) with the standard gauge action and the Wilson quark action with the hopping parameters $\\kappa=0.1600, 0.1625, 0.1650$, and generate about 200 gauge configurations. We measure the temporal correlators of the two-baryon system which consists of heavy-light-light quarks. We extract the inter-baryon force as a function of the relative distance $r$. We also evaluate the contribution to the nuclear force from each ``Feynman diagram'' such as the quark-exchange diagram individually, and single out the roles of Pauli-blocking effects or quark exchanges in the inter-baryon interactions.

T. T. Takahashi; T. Doi; H. Suganuma

2006-01-05T23:59:59.000Z

112

Heavy Quarks, QCD, and Effective Field Theory  

SciTech Connect

The research supported by this OJI award is in the area of heavy quark and quarkonium production, especially the application Soft-Collinear E#11;ective Theory (SCET) to the hadronic production of quarkonia. SCET is an e#11;ffective theory which allows one to derive factorization theorems and perform all order resummations for QCD processes. Factorization theorems allow one to separate the various scales entering a QCD process, and in particular, separate perturbative scales from nonperturbative scales. The perturbative physics can then be calculated using QCD perturbation theory. Universal functions with precise fi#12;eld theoretic de#12;nitions describe the nonperturbative physics. In addition, higher order perturbative QCD corrections that are enhanced by large logarithms can be resummed using the renormalization group equations of SCET. The applies SCET to the physics of heavy quarks, heavy quarkonium, and similar particles.

Thomas Mehen

2012-10-09T23:59:59.000Z

113

Nonperturbative QCD vacuum and Colour Superconductivity  

E-Print Network (OSTI)

We discuss the possibility of existence of colour superconducting state in real QCD vacuum with nonzero gluon condensate. We argue, that nonperturbative gluonic fields might play a crucial role in colour superconductivity scenario.

N. O. Agasian; B. O. Kerbikov; V. I. Shevchenko

1999-02-12T23:59:59.000Z

114

Exploring proton structure using lattice QCD  

E-Print Network (OSTI)

We calculate moments of the generalized parton distributions of the nucleon using lattice QCD. The generalized parton distributions determine the angular momentum decomposition of the nucleon and the transverse distributions ...

Renner, Dru Bryant, 1977-

2004-01-01T23:59:59.000Z

115

Simplifying Multi-Jet QCD Computation  

SciTech Connect

These lectures give a pedagogical discussion of the computation of QCD tree amplitudes for collider physics. The tools reviewed are spinor products, color ordering, MHV amplitudes, and the Britto-Cachazo-Feng-Witten recursion formula.

Peskin, Michael E.; /SLAC

2011-11-04T23:59:59.000Z

116

Probing the 5th Dimension with the QCD String  

E-Print Network (OSTI)

A salient feature of String/Gauge duality is an extra 5th dimension. Here we study the effect of confining deformations of AdS5 and compute the spectrum of a string stretched between infinitely massive quarks and compare it with the quantum states of the QCD flux as determined by Kuti, Juge and Morningstar in lattice simulations. In the long flux tube limit the AdS string probes the metric near the IR cutoff of the 5th dimension with a spectrum approximated by a Nambu-Goto string in 4-d flat space, whereas at short distance the string moves to the UV region with a discrete spectrum for pure AdS5. We also review earlier results on glueballs states and the cross-over between hard and soft diffractive scattering that support this picture.

Richard C. Brower; Chung-I Tan; Ethan Thompson

2005-03-29T23:59:59.000Z

117

The QCD phase diagram: Results and challenges  

Science Conference Proceedings (OSTI)

I review the progress made in recent years with functional methods in our understanding of the QCD phase diagram. In particular I discuss a renormalisation group approach to QCD at finite temperature and chemical potential. Results include the location of the confinement-deconfinement phase transition/cross-over and the chiral phase transition/cross-over lines, their nature as well as their interrelation, and thermodynamic observables.

Pawlowski, Jan M. [Institut fuer Theoretische Physik, Universitaet Heidelberg, Philosophenweg 16, 69120 Heidelberg (Germany); ExtreMe Matter Institute EMMI, GSI, Planckstr. 1, 64291 Darmstadt (Germany)

2011-05-23T23:59:59.000Z

118

Thermodynamics of (2+1)-flavor QCD  

E-Print Network (OSTI)

We report on the status of our QCD thermodynamics project. It is performed on the QCDOC machine at Brookhaven National Laboratory and the APEnext machine at Bielefeld University. Using a 2+1 flavor formulation of QCD at almost realistic quark masses we calculated several thermodynamical quantities. In this proceeding we show the susceptibilites of the chiral condensate and the Polyakov loop, the static quark potential and the spatial string tension.

C. Schmidt; T. Umeda

2006-09-21T23:59:59.000Z

119

Some New/Old Approaches to QCD  

DOE R&D Accomplishments (OSTI)

In this lecture I shall discuss some recent attempts to revive some old ideas to address the problem of solving QCD. I believe that it is timely to return to this problem which has been woefully neglected for the last decade. QCD is a permanent part of the theoretical landscape and eventually we will have to develop analytic tools for dealing with the theory in the infra-red. Lattice techniques are useful but they have not yet lived up to their promise. Even if one manages to derive the hadronic spectrum numerically, to an accuracy of 10% or even 1%, we will not be truly satisfied unless we have some analytic understanding of the results. Also, lattice Monte-Carlo methods can only be used to answer a small set of questions. Many issues of great conceptual and practical interest-in particular the calculation of scattering amplitudes, are thus far beyond lattice control. Any progress in controlling QCD in an explicit analytic, fashion would be of great conceptual value. It would also be of great practical aid to experimentalists, who must use rather ad-hoc and primitive models of QCD scattering amplitudes to estimate the backgrounds to interesting new physics. I will discuss an attempt to derive a string representation of QCD and a revival of the large N approach to QCD. Both of these ideas have a long history, many theorist-years have been devoted to their pursuit-so far with little success. I believe that it is time to try again. In part this is because of the progress in the last few years in string theory. Our increased understanding of string theory should make the attempt to discover a stringy representation of QCD easier, and the methods explored in matrix models might be employed to study the large N limit of QCD.

Gross, D. J.

1992-11-00T23:59:59.000Z

120

THERMODYNAMICS OF (2+1)-FLAVOR QCD.  

SciTech Connect

We report on the status of our QCD thermodynamics project. It is performed on the QCDOC machine at Brookhaven National Laboratory and the APEnext machine at Bielefeld University. Using a 2 + 1 flavor formulation of QCD at almost realistic quark masses we calculated several thermodynamical quantities. In this proceeding we show the susceptibilities of the chiral condensate and the Polyakov loop, the static quark potential and the spatial string tension.

SCHMIDT, C.; UMEDA, T.

2006-10-10T23:59:59.000Z

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


121

Light-front Holography - A New Approach to Relativistic Hadron Dynamics and Nonperturbative QCD  

Science Conference Proceedings (OSTI)

The holographic mapping of gravity in AdS space to QCD, quantized at fixed light-front time, provides a precise relation between the bound-state amplitudes in the fifth dimension of AdS space and the boost-invariant light-front wavefunctions describing the internal structure of hadrons in physical space-time. In particular, the elastic and transition form factors of the pion and the nucleons are well described in this framework. The light-front AdS/QCD holographic approach thus gives a frame-independent first approximation of the color-confining dynamics, spectroscopy, and excitation spectra of relativistic light-quark bound states in QCD. More generally, we show that the valence Fock-state wavefunctions of the eigensolutions of the light-front QCD Hamiltonian satisfy a single-variable relativistic equation of motion, analogous to the nonrelativistic radial Schroedinger equation, with an effective confining potential which systematically incorporates the effects of higher quark and gluon Fock states. The proposed method to compute the effective interaction thus resembles the two-particle-irreducible functional techniques used in quantum field theory.

de Teramond, Guy F.; Brodsky, Stanley J.

2012-06-20T23:59:59.000Z

122

String Approach to QCD Quarks in Fundamental Representations  

E-Print Network (OSTI)

Straightforward use of AdS/CFT correspondence can give QCD with quarks in adjoint representations. Using an asymmetric orbifold approach we obtain nonsupersymmetric QCD with four quark flavors in fundamental representations of color.

Paul H. Frampton

2004-07-12T23:59:59.000Z

123

Electromagnetically superconducting phase of QCD vacuum induced by strong magnetic field  

SciTech Connect

In this talk we discuss our recent suggestion that the QCD vacuum in a sufficiently strong magnetic field (stronger than 10{sup 16} Tesla) may undergo a spontaneous transition to an electromagnetically superconducting state. The possible superconducting state is anisotropic (the vacuum exhibits superconductivity only along the axis of the uniform magnetic field) and inhomogeneous (in the transverse directions the vacuum structure shares similarity with the Abrikosov lattice of an ordinary type-II superconductor). The electromagnetic superconductivity of the QCD vacuum is suggested to occur due to emergence of specific quark-antiquark condensates which carry quantum numbers of electrically charged rho mesons. A Lorentz-covariant generalization of the London transport equations for the magnetic-field-induced superconductivity is given.

Chernodub, M. N. [CNRS, Laboratoire de Mathematiques et Physique Theorique, Universite Francois-Rabelais Tours, Federation Denis Poisson, Parc de Grandmont, 37200 Tours (France); Department of Physics and Astronomy, University of Gent, Krijgslaan 281, S9, B-9000 Gent (Belgium)

2011-05-23T23:59:59.000Z

124

Electromagnetically superconducting phase of QCD vacuum induced by strong magnetic field  

E-Print Network (OSTI)

In this talk we discuss our recent suggestion that the QCD vacuum in a sufficiently strong magnetic field (stronger than 10^{16} Tesla) may undergo a spontaneous transition to an electromagnetically superconducting state. The possible superconducting state is anisotropic (the vacuum exhibits superconductivity only along the axis of the uniform magnetic field) and inhomogeneous (in the transverse directions the vacuum structure shares similarity with the Abrikosov lattice of an ordinary type-II superconductor). The electromagnetic superconductivity of the QCD vacuum is suggested to occur due to emergence of specific quark-antiquark condensates which carry quantum numbers of electrically charged rho mesons. A Lorentz-covariant generalization of the London transport equations for the magnetic-field-induced superconductivity is given.

M. N. Chernodub

2010-11-11T23:59:59.000Z

125

Quantum Money  

Science Conference Proceedings (OSTI)

Quantum Money. Purpose: ... I will present a concrete quantum money scheme based on quantum superpositions of diagrams that encode knots. ...

2011-10-25T23:59:59.000Z

126

QCD String as Vortex String in Seiberg-Dual Theory  

E-Print Network (OSTI)

We construct a classical vortex string solution in a Seiberg-dual theory of N=1 supersymmetric SO(N_c) QCD which flows to a confining phase. We claim that this vortex string is a QCD string, as previouly argued by M.Strassler. In SO(N_c) QCD, it is known that stable QCD strings exist even in the presence of dynamical quarks. We show that our vortex strings are stable in the Seiberg-dual theory.

Eto, Minoru; Terashima, Seiji

2007-01-01T23:59:59.000Z

127

Computing for Perturbative QCD - A Snowmass White Paper  

E-Print Network (OSTI)

We present a study on high-performance computing and large-scale distributed computing for perturbative QCD calculations.

Christian Bauer; Zvi Bern; Radja Boughezal; John Campbell; Neil Christensen; Lance Dixon; Thomas Gehrmann; Stefan Hoeche; Junichi Kanzaki; Alexander Mitov; Pavel Nadolsky; Fredrick Olness; Michael Peskin; Frank Petriello; Stefano Pozzorini; Laura Reina; Frank Siegert; Doreen Wackeroth; Jonathan Walsh; Ciaran Williams; Markus Wobisch

2013-09-13T23:59:59.000Z

128

QCD and Light-Front Dynamics  

SciTech Connect

AdS/QCD, the correspondence between theories in a dilaton-modified five-dimensional anti-de Sitter space and confining field theories in physical space-time, provides a remarkable semiclassical model for hadron physics. Light-front holography allows hadronic amplitudes in the AdS fifth dimension to be mapped to frame-independent light-front wavefunctions of hadrons in physical space-time. The result is a single-variable light-front Schroedinger equation which determines the eigenspectrum and the light-front wavefunctions of hadrons for general spin and orbital angular momentum. The coordinate z in AdS space is uniquely identified with a Lorentz-invariant coordinate {zeta} which measures the separation of the constituents within a hadron at equal light-front time and determines the off-shell dynamics of the bound state wavefunctions as a function of the invariant mass of the constituents. The hadron eigenstates generally have components with different orbital angular momentum; e.g., the proton eigenstate in AdS/QCD with massless quarks has L = 0 and L = 1 light-front Fock components with equal probability. Higher Fock states with extra quark-anti quark pairs also arise. The soft-wall model also predicts the form of the nonperturbative effective coupling and its {beta}-function. The AdS/QCD model can be systematically improved by using its complete orthonormal solutions to diagonalize the full QCD light-front Hamiltonian or by applying the Lippmann-Schwinger method to systematically include QCD interaction terms. Some novel features of QCD are discussed, including the consequences of confinement for quark and gluon condensates. A method for computing the hadronization of quark and gluon jets at the amplitude level is outlined.

Brodsky, Stanley J.; de Teramond, Guy F.; /SLAC /Southern Denmark U., CP3-Origins /Costa Rica U.

2011-01-10T23:59:59.000Z

129

Experimental Study of Nucleon Structure and QCD  

SciTech Connect

Overview of Experimental Study of Nucleon Structure and QCD, with focus on the spin structure. Nucleon (spin) Structure provides valuable information on QCD dynamics. A decade of experiments from JLab yields these exciting results: (1) valence spin structure, duality; (2) spin sum rules and polarizabilities; (3) precision measurements of g{sub 2} - high-twist; and (4) first neutron transverse spin results - Collins/Sivers/A{sub LT}. There is a bright future as the 12 GeV Upgrade will greatly enhance our capability: (1) Precision determination of the valence quark spin structure flavor separation; and (2) Precision extraction of transversity/tensor charge/TMDs.

Jian-Ping Chen

2012-03-01T23:59:59.000Z

130

Quark mass thresholds in QCD thermodynamics  

E-Print Network (OSTI)

We discuss radiative corrections to how quark mass thresholds are crossed, as a function of the temperature, in basic thermodynamic observables such as the pressure, the energy and entropy densities, and the heat capacity of high temperature QCD. The indication from leading order that the charm quark plays a visible role at surprisingly low temperatures, is confirmed. We also sketch a way to obtain phenomenological estimates relevant for generic expansion rate computations at temperatures between the QCD and electroweak scales, pointing out where improvements over the current knowledge are particularly welcome.

M. Laine; Y. Schroder

2006-03-06T23:59:59.000Z

131

Low temperature limit of lattice QCD  

E-Print Network (OSTI)

We study the low temperature limit of lattice QCD by using a reduction formula for a fermion determinant. The reduction formula, which is useful in finite density lattice QCD simulations, contains a reduced matrix defined as the product of $N_t$ block-matrices. It is shown that eigenvalues of the reduced matrix follows a scaling law with regard to the temporal lattice size $N_t$. The $N_t$ scaling law leads to two types of expressions of the fermion determinant in the low temperature limit; one is for small quark chemical potentials, and the other is for larger quark chemical potentials.

Nagata, K; Motoki, S

2012-01-01T23:59:59.000Z

132

Lattice QCD Study for Confinement in Hadrons  

SciTech Connect

We study three subjects on quark confinement in hadrons in SU(3)c lattice QCD. From the accurate lattice calculation for more than 300 different patterns of three-quark (3Q) systems, we find that the static 3Q potential is well described by Y-Ansatz, i.e., the Coulomb plus Y-type linear potential. We also study the multi-quark (4Q, 5Q) potentials in lattice QCD, and find that they are well described by the one-gluon-exchange (OGE) Coulomb plus string-theoretical linear potential, which supports the infrared string picture even for the multi-quarks. The second subject is a lattice-QCD determination of the relevant gluonic momentum component for confinement. The string tension (confining force) is found to be almost unchanged even after cutting off the high-momentum gluon component above 1.5GeV in the Landau gauge. In fact, quark confinement originates from the low-momentum gluon below about 1.5GeV. Finally, we consider a possible gauge of QCD for the quark potential model, by investigating 'instantaneous inter-quark potential' in generalized Landau gauge, which describes a continuous change from the Landau gauge to the Coulomb gauge.

Suganuma, H.; Iritani, T.; Yamamoto, A. [Department of Physics, Kyoto University, Kitashirakawaoiwake, Sakyo, Kyoto 606-8502 (Japan); Okiharu, F. [Faculty of Education, Niigata University, Ikarashi 2-8050, Niigata 950-2181 (Japan); Takahashi, T. T. [Gunma National College of Technology, Maebashi, Gunma 371-8530 (Japan)

2011-10-21T23:59:59.000Z

133

Gauged Axions and their QCD Interactions  

Science Conference Proceedings (OSTI)

We present a brief overview of axion models associated to anomalous abelian (gauge) symmetries, discussing their main phenomenological features. Among these, the mechanism of vacuum misalignment introduced at the QCD and at the electroweak phase transitions, with the appearance of periodic potentials, responsible for the generation of a mass for these types of axions.

Coriano, Claudio; Mariano, Antonio [Dipartimento di Fisica, Universita del Salento and INFN Sezione di Lecce, Via Arnesano 73100 Lecce (Italy); Guzzi, Marco [Department of Physics, Southern Methodist University, Dallas, TX 75275-0175 (United States)

2010-12-22T23:59:59.000Z

134

Visualization Tools for Lattice QCD - Final Report  

Science Conference Proceedings (OSTI)

Our research project is about the development of visualization tools for Lattice QCD. We developed various tools by extending existing libraries, adding new algorithms, exposing new APIs, and creating web interfaces (including the new NERSC gauge connection web site). Our tools cover the full stack of operations from automating download of data, to generating VTK #12;files (topological charge, plaquette, Polyakov lines, quark and meson propagators, currents), to turning the VTK #12;files into images, movies, and web pages. Some of the tools have their own web interfaces. Some Lattice QCD visualization have been created in the past but, to our knowledge, our tools are the only ones of their kind since they are general purpose, customizable, and relatively easy to use. We believe they will be valuable to physicists working in the #12;field. They can be used to better teach Lattice QCD concepts to new graduate students; they can be used to observe the changes in topological charge density and detect possible sources of bias in computations; they can be used to observe the convergence of the algorithms at a local level and determine possible problems; they can be used to probe heavy-light mesons with currents and determine their spatial distribution; they can be used to detect corrupted gauge configurations. There are some indirect results of this grant that will benefit a broader audience than Lattice QCD physicists.

Massimo Di Pierro

2012-03-15T23:59:59.000Z

135

Status Report of NNLO QCD Calculations  

Science Conference Proceedings (OSTI)

We review recent progress in next-to-next-to-leading order (NNLO) perturbative QCD calculations with special emphasis on results ready for phenomenological applications. Important examples are new results on structure functions and jet or Higgs boson production. In addition, we describe new calculational techniques based on twistors and their potential for efficient calculations of multiparticle amplitudes.

Klasen, Michael [Institute for Nuclear Theory, University of Washington, Box 351550, Seattle, WA 98195-1550 (United States)

2005-10-06T23:59:59.000Z

136

QCD parton model at collider energies  

Science Conference Proceedings (OSTI)

Using the example of vector boson production, the application of the QCD improved parton model at collider energies is reviewed. The reliability of the extrapolation to SSC energies is assessed. Predictions at ..sqrt..S = 0.54 TeV are compared with data. 21 references.

Ellis, R.K.

1984-09-01T23:59:59.000Z

137

Heavy quark thermodynamics in full QCD  

E-Print Network (OSTI)

We analyze the large-distance behaviour of static quark-anti-quark pair correlations in QCD. The singlet free energy is calculated and the entropy contribution to it is identified allowing us to calculate the excess internal energy. The free energy has a sharp drop in the critical region, leading to sharp peaks in both excess entropy and internal energy.

Konstantin Petrov; RBC-Bielefeld Collaboration

2007-01-22T23:59:59.000Z

138

In the debris of hadron interactions lies the beauty of QCD  

E-Print Network (OSTI)

Recent progress in understanding the strong physics regime of QCD is described. The role played by condensates, particularly $q{\\bar q}$, in breaking chiral symmetry and generating constituent masses for $u$ and $d$ quarks is reviewed. The influence this has on hadrons with vacuum quantum numbers is emphasised. What we know of this sector from recent data on $\\phi$-radiative decays and from $D$ decays to light hadrons is discussed. The key to further understanding is comprehensive analyses of such data, including that planned for Hall D at Jefferson Laboratory.

M. R. Pennington

2003-09-19T23:59:59.000Z

139

Quantum groups  

Science Conference Proceedings (OSTI)

The theory of Quantum groups, although rather young, since the expression Quantum ... introduction of a suitable form of the quantum group, the algebra A ...

140

MAGNETIC FIELDS FROM QCD PHASE TRANSITIONS  

SciTech Connect

We study the evolution of QCD phase transition-generated magnetic fields (MFs) in freely decaying MHD turbulence of the expanding universe. We consider an MF generation model that starts from basic non-perturbative QCD theory and predicts stochastic MFs with an amplitude of the order of 0.02 {mu}G and small magnetic helicity. We employ direct numerical simulations to model the MHD turbulence decay and identify two different regimes: a 'weakly helical' turbulence regime, when magnetic helicity increases during decay, and 'fully helical' turbulence, when maximal magnetic helicity is reached and an inverse cascade develops. The results of our analysis show that in the most optimistic scenario the magnetic correlation length in the comoving frame can reach 10 kpc with the amplitude of the effective MF being 0.007 nG. We demonstrate that the considered model of magnetogenesis can provide the seed MF for galaxies and clusters.

Tevzadze, Alexander G. [Faculty of Exact and Natural Sciences, Javakhishvili Tbilisi State University, 1 Chavchavadze Avenue, Tbilisi 0128 (Georgia); Kisslinger, Leonard; Kahniashvili, Tina [McWilliams Center for Cosmology and Department of Physics, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA 15213 (United States); Brandenburg, Axel, E-mail: aleko@tevza.org [Nordita, KTH Royal Institute of Technology and Stockholm University, Roslagstullsbacken 23, SE-10691 Stockholm (Sweden)

2012-11-01T23:59:59.000Z

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


141

Effective string theory and QCD scattering amplitudes  

Science Conference Proceedings (OSTI)

QCD string is formed at distances larger than the confinement scale and can be described by the Polchinski-Strominger effective string theory with a nonpolynomial action, which has nevertheless a well-defined semiclassical expansion around a long-string ground state. We utilize modern ideas about the Wilson-loop/scattering-amplitude duality to calculate scattering amplitudes and show that the expansion parameter in the effective string theory is small in the Regge kinematical regime. For the amplitudes we obtain the Regge behavior with a linear trajectory of the intercept (d-2)/24 in d dimensions, which is computed semiclassically as a momentum-space Luescher term, and discuss an application to meson scattering amplitudes in QCD.

Makeenko, Yuri [Institute of Theoretical and Experimental Physics, B. Cheremushkinskaya 25, 117218 Moscow (Russian Federation)

2011-01-15T23:59:59.000Z

142

Nuclear physics from strong coupling QCD  

E-Print Network (OSTI)

The strong coupling limit (beta_gauge = 0) of QCD offers a number of remarkable research possibilities, of course at the price of large lattice artifacts. Here, we determine the complete phase diagram as a function of temperature T and baryon chemical potential mu_B, for one flavor of staggered fermions in the chiral limit, with emphasis on the determination of a tricritical point and on the T ~ 0 transition to nuclear matter. The latter is known to happen for mu_B substantially below the baryon mass, indicating strong nuclear interactions in QCD at infinite gauge coupling. This leads us to studying the properties of nuclear matter from first principles. We determine the nucleon-nucleon potential in the strong coupling limit, as well as masses m_A of nuclei as a function of their atomic number A. Finally, we clarify the origin of nuclear interactions at strong coupling, which turns out to be a steric effect.

Michael Fromm; Philippe de Forcrand

2009-12-14T23:59:59.000Z

143

B production at the LHC / QCD aspects  

E-Print Network (OSTI)

The LHC provides new opportunities to improve our understanding of the b quark using high statistics data samples and the 14 TeV center-of-mass energy. The prospects to measure the cross section for inclusive b production in events containing jets and at least one muon are presented. Studies of detector systematic effects and theoretical uncertainties are included. QCD aspects of the beauty production are discussed.

Valery P. Andreev

2007-06-12T23:59:59.000Z

144

Hadron physics as Seiberg dual of QCD  

SciTech Connect

We try to identify the light hadron world as the magnetic picture of QCD. We take both phenomenological and theoretical approaches to this hypothesis, and find that the interpretation seems to show interesting consistencies. In particular, one can identify the {rho} and {omega} mesons as the magnetic gauge bosons, and the Higgs mechanism for them provides a dual picture of the color confinement{sup 1}.

Kitano, Ryuichiro [Department of Physics, Tohoku University, Sendai 980-8578 (Japan)

2012-07-27T23:59:59.000Z

145

QCD, Symmetry Breaking and the Random Lattice  

E-Print Network (OSTI)

According to the Nielsen-Ninomiya No-Go theorem, the doubling of fermions on the lattice cannot be suppressed in a chiral theory. Whereas Wilson and staggered fermions suppress doublers with explicit breaking of chiral symmetry, the random lattice does so by spontaneous chiral symmetry breaking even in the free theory. I present results for meson masses, the chiral condensate and fermionic eigenvalues from simulations of quenched QCD on random lattices in four dimensions, focusing on chiral symmetry breaking. 1.

Saul D. Cohen A

2006-01-01T23:59:59.000Z

146

QCD corrections to Higgs boson production  

SciTech Connect

We discuss the O({alpha}{sub s}) QCD radiative corrections to Higgs boson production in the limit in which the top quark is much heavier than the Higgs boson. The subleading corrections, of O({alpha}{sub s}M{sub H}{sup 2}/M{sub top}{sup 2}), are presented for the decay H {yields} {gamma}{gamma} and shown to be small.

Dawson, S.

1992-11-01T23:59:59.000Z

147

QCD corrections to Higgs boson production  

SciTech Connect

We discuss the O([alpha][sub s]) QCD radiative corrections to Higgs boson production in the limit in which the top quark is much heavier than the Higgs boson. The subleading corrections, of O([alpha][sub s]M[sub H][sup 2]/M[sub top][sup 2]), are presented for the decay H [yields] [gamma][gamma] and shown to be small.

Dawson, S.

1992-11-01T23:59:59.000Z

148

Lattice QCD simulation at finite chiral chemical potential  

E-Print Network (OSTI)

Chiral chemical potential does not cause the sign problem in the Monte Carlo simulation of lattice QCD. Using the chiral chemical potential, we study the chiral magnetic effect in two-flavor full QCD. We show that a strong external magnetic field induces an electric current in a chirally imbalanced QCD matter. The qualitative feature of the induced current is consistent with an analytical prediction.

Yamamoto, Arata

2011-01-01T23:59:59.000Z

149

Astrophysical Implications of the QCD Phase Transition  

Science Conference Proceedings (OSTI)

The possible role of a first order QCD phase transition at nonvanishing quark chemical potential and temperature for cold neutron stars and for supernovae is delineated. For cold neutron stars, we use the NJL model with a nonvanishing color superconducting pairing gap, which describes the phase transition to the 2SC and the CFL quark matter phases at high baryon densities. We demonstrate that these two phase transitions can both be present in the core of neutron stars and that they lead to the appearance of a third family of solution for compact stars. In particular, a core of CFL quark matter can be present in stable compact star configurations when slightly adjusting the vacuum pressure to the onset of the chiral phase transition from the hadronic model to the NJL model. We show that a strong first order phase transition can have a strong impact on the dynamics of core collapse supernovae. If the QCD phase transition sets in shortly after the first bounce, a second outgoing shock wave can be generated which leads to an explosion. The presence of the QCD phase transition can be read off from the neutrino and antineutrino signal of the supernova.

Schaffner-Bielich, J. [Ruprecht-Karls-Universitaet, Heidelberg, Germany; Sagert, I. [Goethe University, Frankfurt, Germany; Hempel, M. [Goethe University, Frankfurt, Germany; Pagliara, G. [Ruprecht-Karls-Universitaet, Heidelberg, Germany; Fischer, T. [University of Basel; Mezzacappa, Anthony [ORNL; Thielemann, Friedrich-Karl W. [Universitat Basel, Switzerland; Liebendoerfer, Matthias [Universitat Basel, Switzerland

2009-01-01T23:59:59.000Z

150

A Bayesian approach to QCD sum rules  

E-Print Network (OSTI)

QCD sum rules are analyzed with the help of the Maximum Entropy Method. We develop a new technique based on the Bayesion inference theory, which allows us to directly obtain the spectral function of a given correlator from the results of the operator product expansion given in the deep euclidean 4-momentum region. The most important advantage of this approach is that one does not have to make any a priori assumptions about the functional form of the spectral function, such as the "pole + continuum" ansatz that has been widely used in QCD sum rule studies, but only needs to specify the asymptotic values of the spectral function at high and low energies as an input. As a first test of the applicability of this method, we have analyzed the sum rules of the rho-meson, a case where the sum rules are known to work well. Our results show a clear peak structure in the region of the experimental mass of the rho-meson. We thus demonstrate that the Maximum Entropy Method is successfully applied and that it is an efficient tool in the analysis of QCD sum rules.

Philipp Gubler; Makoto Oka

2010-05-14T23:59:59.000Z

151

Continuous Wavelet Transform in Quantum Field Theory  

E-Print Network (OSTI)

We describe the application of the continuous wavelet transform to calculation of the Green functions in quantum field theory: scalar $\\phi^4$ theory, quantum electrodynamics, quantum chromodynamics. The method of continuous wavelet transform in quantum field theory presented in M.Altaisky Phys. Rev. D81(2010)125003 for the scalar $\\phi^4$ theory, consists in substitution of the local fields $\\phi(x)$ by those dependent on both the position $x$ and the resolution $a$. The substitution of the action $S[\\phi(x)]$ by the action $S[\\phi_a(x)]$ makes the local theory into nonlocal one, and implies the causality conditions related to the scale $a$, the region causality C. Christensen and L. Crane, J.Math. Phys 46 (2005) 122502. These conditions make the Green functions $G(x_1,a_1,..., x_n,a_n)= $ finite for any given set of regions by means of an effective cutoff scale $A=\\min (a_1,...,a_n)$.

Altaisky, Mikhail V

2013-01-01T23:59:59.000Z

152

QCD analysis of structure functions in terms of Jacobi polynomials  

Science Conference Proceedings (OSTI)

z Tbilisi State University, SU-380 086 Tbilisi, USSR. Received 21 August 1986. Abstract. A new method of QCD-analysis of singlet and nonsinglet structure ...

153

QCD phase diagram at imaginary baryon and isospin chemical potentials  

E-Print Network (OSTI)

We explore the phase diagram of two-flavor QCD at imaginary values of baryon and isospin chemical potentials analyzing the thermodynamic potential of QCD analytically and that of the Polyakov-loop extended Nambu-Jona-Lasinio (PNJL) model numerically. QCD has no pion condensation at imaginary baryon and isospin chemical potentials, and therefore has discrete symmetries that are not present at real baryon and isospin chemical potentials. The PNJL model possesses all the discrete symmetries. The PNJL model can reproduce qualitatively lattice QCD data presented very lately.

Sakai, Yuji; Yahiro, Masanobu

2009-01-01T23:59:59.000Z

154

Light Baryons from 2+1 flavor DWF QCD  

E-Print Network (OSTI)

We present results from the RBC and UKQCD collaboration ensembles of 2+1 flavor DWF QCD for the light baryon spectrum.

C. M. Maynard; RBC; UKQCD collaborations

2010-01-28T23:59:59.000Z

155

Chiral Magnetic Effect and the QCD Phase Transitions  

SciTech Connect

We summarize the idea of the chiral magnetic effect and the observables relevant to the heavy-ion collision experiment which could be affected by QCD phase transitions.

Fukushima, Kenji [Department of Physics, Keio University, Kanagawa 223-8522 (Japan)

2011-05-23T23:59:59.000Z

156

Quantum Cryptography and Quantum Computation  

E-Print Network (OSTI)

Quantum Cryptography and Quantum Computation Network Security Course Project Report by Hidayath.2 Bases of the Hilbert space . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2.3 Quantum principle . . . . . . . . . . . . . . . . . . . . . . 5 3 Quantum Cryptography 6 3.1 The BB84 protocol

North Carolina at Chapel Hill, University of

157

Transforming quantum operations: quantum supermaps  

E-Print Network (OSTI)

We introduce the concept of quantum supermap, describing the most general transformation that maps an input quantum operation into an output quantum operation. Since quantum operations include as special cases quantum states, effects, and measurements, quantum supermaps describe all possible transformations between elementary quantum objects (quantum systems as well as quantum devices). After giving the axiomatic definition of supermap, we prove a realization theorem, which shows that any supermap can be physically implemented as a simple quantum circuit. Applications to quantum programming, cloning, discrimination, estimation, information-disturbance trade-off, and tomography of channels are outlined.

G. Chiribella; G. M. D'Ariano; P. Perinotti

2008-04-01T23:59:59.000Z

158

QCD Phase Diagram Using Dyson-Schwinger Equations  

Science Conference Proceedings (OSTI)

We describe briefly the Dyson-Schwinger equation approach of QCD and the study of the QCD phase diagram in this approach. The phase diagram in terms of the temperature and chemical potential, and that in the space of coupling strength and current-quark mass are given.

Liu Yuxin; Qin Sixue; Chang Lei [Department of Physics, Center for High Energy Physics and the State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China); Roberts, Craig D. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Department of Physics, Center for High Energy Physics and the State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China)

2011-05-24T23:59:59.000Z

159

Yukawa's Pion, Low-Energy QCD and Nuclear Chiral Dynamics  

E-Print Network (OSTI)

A survey is given of the evolution from Yukawa's early work, via the understanding of the pion as a Nambu-Goldstone boson of spontaneously broken chiral symmetry in QCD, to modern developments in the theory of the nucleus based on the chiral effective field theory representing QCD in its low-energy limit.

Weise, Wolfram

2007-01-01T23:59:59.000Z

160

Continuing Progress on a Lattice QCD Software Infrastructure  

E-Print Network (OSTI)

We report on the progress of the software effort in the QCD Application Area of SciDAC. In particular, we discuss how the software developed under SciDAC enabled the aggressive exploitation of leadership computers, and we report on progress in the area of QCD software for multi-core architectures.

Balint Joo; for the USQCD Collaboration

2008-06-13T23:59:59.000Z

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


161

Pseudoscalar Higgs boson production at hadron colliders in NNLO QCD  

SciTech Connect

We compute the total cross-section for direct production of the pseudoscalar Higgs boson in hadron collisions at next-to-next-to-leading order (NNLO) in perturbative QCD. The {Omicron}({alpha}{sub s}{sup 2}) QCD corrections increase the NLO production cross-section by approximately 20-30%.

Anastasiou, Charalampos

2002-08-26T23:59:59.000Z

162

An Experimenter's View of Lattice QCD  

E-Print Network (OSTI)

Lattice QCD has the potential this decade to maximize the sensitivity of the entire flavor physics program to new physics and pave the way for understanding physics beyond the Standard Model at the LHC in the coming decade. However, the challenge for the Lattice is to demonstrate reliability at the level of a few per cent given a past history of 10-20% errors. The CLEO-c program at the Cornell Electron Storage Ring is providing the data that will make the demonstration possible.

I. Shipsey

2004-11-05T23:59:59.000Z

163

Light-Front Quantization and QCD Phenomena  

E-Print Network (OSTI)

The light-front quantization of QCD provides an alternative to lattice gauge theory for computing the mass spectrum, scattering amplitudes, and other physical properties of hadrons directly in Minkowski space. Nonperturbative light-front methods for solving gauge theory and obtaining light-front wavefunctions, such as discretized light-front quantization, the transverse lattice, and light-front resolvents are reviewed. The resulting light-front wavefunctions give a frame-independent interpolation between hadrons and their quark and gluon degrees of freedom, including an exact representation of spacelike form factors, transition form factors such as $B \\to \\ell \\bar \

S. J. Brodsky

2003-11-05T23:59:59.000Z

164

QCD on GPUs: cost effective supercomputing  

E-Print Network (OSTI)

The exponential growth of floating point power in graphics processing units (GPUs), together with their low cost, has given rise to an attractive platform upon which to deploy lattice QCD calculations. GPUs are essentially many (O(100)) core chips, that are programmed using a massively threaded environment, and so are representative of the future of high performance computing (HPC). The large ratio of raw floating point operations per second to memory bandwidth that is characteristic of GPUs necessitates that unique algorithmic design choices are made to harness their full potential. We review the progress to date in using GPUs for large scale calculations, and contrast GPUs against more traditional HPC architectures

M. A. Clark

2009-12-11T23:59:59.000Z

165

Physical Nucleon Form Factors from Lattice QCD  

Science Conference Proceedings (OSTI)

We explore the possibility of extrapolating state of the art lattice QCD calculations of nucleon electromagnetic form factors to the physical regime. We find that the lattice results can be reproduced using the Light Front Cloudy Bag Model by letting its parameters be analytic functions of the quark mass. We then use the model to extrapolate the lattice result to the physical value of the pion mass, thereby allowing us to study how the predicted zero in GE(Q2)/GM(Q2) for proton varies as a function of quark mass.

Matevosyan, Hrayr H. [Louisiana State University, Department of Physics and Astronomy, 202 Nicholson Hall, Tower Dr., Baton Rouge, LA 70803 (United States); Thomas Jefferson National Accelerator Facility, 12000 Jefferson Ave., Newport News, VA 23606 (United States); Miller, Gerald A. [University of Washington, Department of Physics, Box 351560, Seattle, WA 98195-1560 (United States); Thomas, Anthony W. [Thomas Jefferson National Accelerator Facility, 12000 Jefferson Ave., Newport News, VA 23606 (United States)

2006-07-11T23:59:59.000Z

166

Quantum Tetrahedra  

E-Print Network (OSTI)

We discuss in details the role of Wigner 6j symbol as the basic building block unifying such different fields as state sum models for quantum geometry, topological quantum field theory, statistical lattice models and quantum computing. The apparent twofold nature of the 6j symbol displayed in quantum field theory and quantum computing -a quantum tetrahedron and a computational gate- is shown to merge together in a unified quantum-computational SU(2)-state sum framework.

Mauro Carfora; Annalisa Marzuoli; Mario Rasetti

2010-01-25T23:59:59.000Z

167

LANL | Physics | Nuclear Physics  

NLE Websites -- All DOE Office Websites (Extended Search)

of quantum chromodynamics Quantum chromodynamics is the theory that the strong nuclear force holds together the atomic nucleus. We lead experiments at the Relativistic...

168

Electron Ion Collider: The Next QCD Frontier  

NLE Websites -- All DOE Office Websites (Extended Search)

Ion Collider: Ion Collider: The Next QCD Frontier Understanding the glue that binds us all Electron Ion Collider: The Next QCD Frontier Understanding the glue that binds us all BNL-98815-2012-JA JLAB-PHY-12-1652 arXiv:1212.1701 Authors A. Accardi 14,28 , J. L. Albacete 16 , M. Anselmino 29 , N. Armesto 36 , E. C. Aschenauer 3,† , A. Bacchetta 35 , D. Boer 33 , W. Brooks 37,† , T. Burton 3 , N.-B. Chang 23 , W.-T. Deng 13,23 , A. Deshpande 25,∗,† , M. Diehl 11,† , A. Dumitru 2 , R. Dupr´ e 7 , R. Ent 28,‡ , S. Fazio 3 , H. Gao 12,† , V. Guzey 28 , H. Hakobyan 37 , Y. Hao 3 , D. Hasch 15 , R. Holt 1,† , T. Horn 5,† , M. Huang 23 , A. Hutton 28,† , C. Hyde 20 , J. Jalilian-Marian 2 , S. Klein 17 , B. Kopeliovich 37 , Y. Kovchegov 19,† , K. Kumar 24,† , K. Kumeriˇ cki 40 , M. A. C. Lamont 3 , T. Lappi 34 , J.-H. Lee 3 , Y. Lee 3 , E. M. Levin 26,37 , F.-L. Lin 28 , V. Litvinenko 3 , T. W. Ludlam 3,‡ , C. Marquet

169

AdS/QCD and Applications of Light-Front Holography  

SciTech Connect

Light-Front Holography leads to a rigorous connection between hadronic amplitudes in a higher dimensional anti-de Sitter (AdS) space and frame-independent light-front wavefunctions of hadrons in 3 + 1 physical space-time, thus providing a compelling physical interpretation of the AdS/CFT correspondence principle and AdS/QCD, a useful framework which describes the correspondence between theories in a modified AdS5 background and confining field theories in physical space-time. To a first semiclassical approximation, where quantum loops and quark masses are not included, this approach leads to a single-variable light-front Schroedinger equation which determines the eigenspectrum and the light-front wavefunctions of hadrons for general spin and orbital angular momentum. The coordinate z in AdS space is uniquely identified with a Lorentz-invariant coordinate {zeta} which measures the separation of the constituents within a hadron at equal light-front time. The internal structure of hadrons is explicitly introduced and the angular momentum of the constituents plays a key role. We give an overview of the light-front holographic approach to strongly coupled QCD. In particular, we study the photon-to-meson transition form factors (TFFs) F{sub M{gamma}}(Q{sup 2}) for {gamma}{gamma}* {yields} M using light-front holographic methods. The results for the TFFs for the {eta} and {eta}' mesons are also presented. Some novel features of QCD are discussed, including the consequences of confinement for quark and gluon condensates. A method for computing the hadronization of quark and gluon jets at the amplitude level is outlined.

Brodsky, Stanley J.; /SLAC /Southern Denmark U., CP3-Origins; Cao, Fu-Guang; /Massey U.; de Teramond, Guy F.; /Costa Rica U.

2012-02-16T23:59:59.000Z

170

Recent results on QCD thermodynamics: lattice QCD versus Hadron Resonance Gas model  

E-Print Network (OSTI)

We present our most recent investigations on the QCD cross-over transition temperatures with 2+1 staggered flavours and one-link stout improvement [JHEP 1009:073, 2010]. We extend our previous two studies [Phys. Lett. B643 (2006) 46, JHEP 0906:088 (2009)] by choosing even finer lattices ($N_t$=16) and we work again with physical quark masses. All these results are confronted with the predictions of the Hadron Resonance Gas model and Chiral Perturbation Theory for temperatures below the transition region. Our results can be reproduced by using the physical spectrum in these analytic calculations. A comparison with the results of the hotQCD collaboration is also discussed.

Szabolcs Borsanyi; Zoltan Fodor; Christian Hoelbling; Sandor D. Katz; Stefan Krieg; Claudia Ratti; Kalman K. Szabo

2010-12-23T23:59:59.000Z

171

Handbook Article on Applications of Random Matrix Theory to QCD  

E-Print Network (OSTI)

In this chapter of the Oxford Handbook of Random Matrix Theory we introduce chiral Random Matrix Theories with the global symmetries of QCD. In the microscopic domain, these theories reproduce the mass and chemical potential dependence of QCD. The main focus of this chapter is on the spectral properties of the QCD Dirac operator and relations between chiral Random Matrix Theories and chiral Lagrangians. Both spectra of the anti-hermitian Dirac operator and spectra of the nonhermitian Dirac operator at nonzero chemical potential are discussed.

J. J. M. Verbaarschot

2009-10-21T23:59:59.000Z

172

Handbook Article on Applications of Random Matrix Theory to QCD  

E-Print Network (OSTI)

In this chapter of the Oxford Handbook of Random Matrix Theory we introduce chiral Random Matrix Theories with the global symmetries of QCD. In the microscopic domain, these theories reproduce the mass and chemical potential dependence of QCD. The main focus of this chapter is on the spectral properties of the QCD Dirac operator and relations between chiral Random Matrix Theories and chiral Lagrangians. Both spectra of the anti-hermitian Dirac operator and spectra of the nonhermitian Dirac operator at nonzero chemical potential are discussed.

Verbaarschot, J J M

2009-01-01T23:59:59.000Z

173

Status of Average-x from Lattice QCD  

Science Conference Proceedings (OSTI)

As algorithms and computing power have advanced, lattice QCD has become a precision technique for many QCD observables. However, the calculation of nucleon matrix elements remains an open challenge. I summarize the status of the lattice effort by examining one observable that has come to represent this challenge, average-x: the fraction of the nucleon's momentum carried by its quark constituents. Recent results confirm a long standing tendency to overshoot the experimentally measured value. Understanding this puzzle is essential to not only the lattice calculation of nucleon properties but also the broader effort to determine hadron structure from QCD.

Dru Renner

2011-09-01T23:59:59.000Z

174

Towards a consistent AdS/QCD dictionary  

E-Print Network (OSTI)

This note focuses on the large-N behaviour of the Hard Wall model of QCD and clarifies the AdS/QCD dictionary formulated on the basis of the AdS/CFT correspondence. It is shown how short-distance studies performed in the framework of the AdS/QCD Soft Wall model allow one to determine unambiguously the chiral symmetry breaking function in the Hard Wall model. Especially, the different forms of the field/operator prescription are emphasized. The large-N behaviour of the Hard Wall model is then checked considering the vector and gravitational form factors of the pion in the chiral limit.

Frederic Jugeau

2009-02-23T23:59:59.000Z

175

lqcd.dvi  

NLE Websites -- All DOE Office Websites (Extended Search)

Lattice Lattice QCD 1 1. LATTICE QUANTUM CHROMODYNAMICS Updated September 2013 by S. Hashimoto (KEK), J. Laiho (Syracuse University) and S.R. Sharpe (University of Washington). 1.1. Lattice regularization of QCD Gauge theories form the building blocks of the Standard Model. While the SU(2) and U(1) parts have weak couplings and can be studied accurately with perturbative methods, the SU(3) component-QCD-is only amenable to a perturbative treatment at high energies. The growth of the coupling constant in the infrared-the flip-side of asymptotic freedom-requires the use of non-perturbative methods to determine the low energy properties of QCD. Lattice gauge theory, proposed by K. Wilson in 1974 [1], provides such a method, for it gives a non-perturbative definition of vector-like gauge field theories like QCD. In lattice regularized QCD-commonly called lattice QCD or LQCD-Euclidean

176

Exotic and excited-state radiative transitions in charmonium from lattice QCD  

E-Print Network (OSTI)

We compute, for the first time using lattice QCD methods, radiative transition rates involving excited charmonium states, states of high spin and exotics. Utilizing a large basis of interpolating fields we are able to project out various excited state contributions to three-point correlators computed on quenched anisotropic lattices. In the first lattice QCD calculation of the exotic 1-+ eta_c1 radiative decay, we find a large partial width Gamma(eta_c1 -> J/psi gamma) ~ 100 keV. We find clear signals for electric dipole and magnetic quadrupole transition form factors in chi_c2 -> J/psi gamma, calculated for the first time in this framework, and study transitions involving excited psi and chi_c1,2 states. We calculate hindered magnetic dipole transition widths without the sensitivity to assumptions made in model studies and find statistically significant signals, including a non-exotic vector hybrid candidate Y_hyb? -> eta_c gamma. As well as comparison to experimental data, we discuss in some detail the phenomenology suggested by our results and the extent to which it mirrors that of quark potential models and make suggestions for the interpretation of our results involving exotic quantum numbered states.

Jozef Dudek; Robert Edwards; Christopher Thomas

2009-02-13T23:59:59.000Z

177

Hadron interactions from SU(2) lattice QCD  

Science Conference Proceedings (OSTI)

We evaluate interhadron interactions in quenched two-color lattice QCD from Bethe-Salpeter amplitudes, concentrating on S-wave scattering states of two scalar diquarks (uC{gamma}5d). Between two identical scalar diquarks, we observe repulsion in short-range region. We define and evaluate the 'quark-exchange part' in the interaction, which is induced by adding quark-exchange diagrams, or equivalently, by introducing Pauli blocking among some of quarks. The repulsive force in short-distance region arises only from the 'quark-exchange part', and disappears when quark-exchange diagrams are omitted, which is qualitatively consistent with the constituent-quark model picture that a color-magnetic interaction among quarks is the origin of repulsion. We also find a universal long-range attractive force, which enters in any flavor channels of two scalar diquarks and whose interaction range and strength are quark-mass independent.

Takahashi, Toru T. [Gunma National College of Technology, Maebashi, Gunma 371-8530 (Japan); Kanada-En'yo, Yoshiko [Department of Physics, Kyoto University, Sakyo, Kyoto 606-8502 (Japan)

2011-10-21T23:59:59.000Z

178

Electroweak and QCD Results from the Tevatron  

SciTech Connect

The Tevatron collider has been remarkably successful and has so far delivered more than 11 fb{sup -1} of data to both the CDF and D0 experiments. Though the LHC has replaced the Tevatron as the world's most powerful collider, years of detector calibration, the huge size of the dataset and the nature of pp collisions will keep the Tevatron competitive in many selected topics in the near future. More than 10 fb{sup -1} of data has been collected by each experiment. Good understanding of the detector performance has been demonstrated by the high precision W boson mass ({Delta}M{sub W} = 31 MeV) and top quark mass ({Delta}M{sub t} = 1.06 GeV) measurements. We report the latest electroweak and QCD results from both experiments. Most analyses presented here used 4-6 fb{sup -1} of data.

Zhu, Junjie; /Michigan U.

2011-09-01T23:59:59.000Z

179

Subcritical string and large N QCD  

Science Conference Proceedings (OSTI)

We pursue the possibility of using subcritical string theory in 4 spacetime dimensions to establish a string dual for large N QCD. In particular we study the even G-parity sector of the 4 dimensional Neveu-Schwarz dual resonance model as the natural candidate for this string theory. Our point of view is that the open string dynamics given by this model will determine the appropriate subcritical closed string theory, a tree level background of which should describe the sum of planar multiloop open string diagrams. We examine the one-loop open string diagram, which contains information about the closed string spectrum at weak coupling. Higher loop open string diagrams will be needed to determine closed string interactions. We also analyze the field theory limit of the one-loop open string diagram and recover the correct running coupling behavior of the limiting gauge theory.

Thorn, Charles B. [Institute for Fundamental Theory, Department of Physics, University of Florida, Gainesville Florida 32611 (United States)

2008-10-15T23:59:59.000Z

180

Subcritical String and Large N QCD  

E-Print Network (OSTI)

We pursue the possibility of using subcritical string theory in 4 space-time dimensions to establish a string dual for large N QCD. In particular we study the even G-parity sector of the 4 dimensional Neveu-Schwarz dual resonance model as the natural candidate for this string theory. Our point of view is that the open string dynamics given by this model will {\\it determine} the appropriate subcritical closed string theory, a tree level background of which should describe the sum of planar multi-loop open string diagrams. We examine the one loop open string diagram, which contains information about the closed string spectrum at weak coupling. Higher loop open string diagrams will be needed to determine closed string interactions. We also analyze the field theory limit of the one loop open string diagram and recover the correct running coupling behavior of the limiting gauge theory.

Thorn, Charles B

2008-01-01T23:59:59.000Z

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


181

Higgs picture of the QCD-vacuum  

E-Print Network (OSTI)

The functional integral for QCD is reformulated by introducing explicitly an integration over the fluctuations of composite quark-antiquark bound states. Chiral symmetry breaking by the color singlet scalar field induces masses for the fermions. Our formulation with scalar fluctuations may be useful for lattice gauge theories by modifying the spectrum of the Dirac operator in the vacuum and permitting a simple connection to chiral perturbation theory. We propose that a ``condensate'' of quark-antiquark bound states in the color octet channel generates masses of the gluons by the Higgs mechanism. A simple effective action for quarks, gluons and (composite) scalars yields a surprisingly good description of the charges, masses and interactions of all low mass physical excitations - baryons, pseudoscalars and vector mesons. Dressed quarks appear as baryons and dressed gluons as vector mesons.

C. Wetterich

2004-10-04T23:59:59.000Z

182

Feynman rules for Coulomb gauge QCD  

Science Conference Proceedings (OSTI)

The Coulomb gauge in nonabelian gauge theories is attractive in principle, but beset with technical difficulties in perturbation theory. In addition to ordinary Feynman integrals, there are, at 2-loop order, Christ-Lee (CL) terms, derived either by correctly ordering the operators in the Hamiltonian, or by resolving ambiguous Feynman integrals. Renormalization theory depends on the sub-graph structure of ordinary Feynman graphs. The CL terms do not have a sub-graph structure. We show how to carry out renormalization in the presence of CL terms, by re-expressing these as 'pseudo-Feynman' integrals. We also explain how energy divergences cancel. - Highlights: Black-Right-Pointing-Pointer In Coulomb gauge QCD, we re-express Christ-Lee terms in the Hamiltonian as pseudo-Feynman integrals. Black-Right-Pointing-Pointer This gives a subgraph structure, and allows the ordinary renormalization process. Black-Right-Pointing-Pointer It also leads to cancellation of energy-divergences.

Andrasi, A. [Rudjer Boskovic Institute, Zagreb (Croatia)] [Rudjer Boskovic Institute, Zagreb (Croatia); Taylor, J.C., E-mail: jct@damtp.cam.ac.uk [Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Cambridge (United Kingdom)

2012-10-15T23:59:59.000Z

183

Bounds on free energy in QCD  

E-Print Network (OSTI)

We derive some exact bounds on the free energy $W(J)$ in QCD, where $J_\\mu^b$ is a source for the gluon field $A_\\mu^b$ in the minimal Landau gauge, and $W(J)$ is the generating functional of connected gluon correlators. Among other results, we show that for a static source $J(x) = h$ the free energy vanishes, $W(h) = 0$, together with its first derivative, ${\\partial W(h) \\over \\partial h} = 0,$ for all $h$, no matter how strong. Thus the system does not respond to a static color probe. We also present numerical evaluations of the free energy $W(J)$ and find that the bounds are well satisfied and in fact undersaturated.

Axel Maas; Daniel Zwanziger

2013-01-15T23:59:59.000Z

184

Quantum discord  

NLE Websites -- All DOE Office Websites (Extended Search)

Quantum discord Quantum discord 1663 Los Alamos science and technology magazine Latest Issue:November 2013 All Issues » submit Quantum discord A distinguishing aspect of quantum mechanics discovered at Los Alamos that may be critical to building a quantum computer March 25, 2013 Spinning coins turning into binary numbers Quantum computing Quantum computing can be carried out without the delicate entanglement of qubits previously believed to be necessary Quantum computing, in which quantum bits of information (or qubits) juggle a "superposition" of multiple values simultaneously, offers to unleash tremendous computational power if the qubits can be effectively isolated to prevent decoherence: information describing quantum states dispersing into the environment. But recent research has shown that quantum computing can be carried out

185

Quantum Institute  

NLE Websites -- All DOE Office Websites (Extended Search)

Quantum Institute Quantum Institute Quantum Institute A new research frontier awaits! Our door is open and we thrive on mutually beneficial partnerships, collaborations that drive innovations and new technologies. Contact Leader Malcolm Boshier (505) 665-8892 Email Two of LANL's most successful quantum technology initiatives: quantum cryptography and the race for quantum computer The area of quantum information, science, and technology is rapidly evolving, with important applications in the areas of quantum cryptography, quantum computing, quantum metrology, and advanced quantum-based sensors, some of which are directly relevant to the Laboratory's national security mission. Mission Foster a vigorous intellectual environment at LANL Define and develop strategic thrusts Target and pursue funding opportunities

186

Strange and charm meson masses from twisted mass lattice QCD  

E-Print Network (OSTI)

We present first results of a 2+1+1 flavor twisted mass lattice QCD computation of strange and charm meson masses. We focus on D and D_s mesons with spin J = 0,1 and parity P = -,+.

Martin Kalinowski; Marc Wagner

2012-12-03T23:59:59.000Z

187

Strongly coupled plasmas and the QCD critical point  

E-Print Network (OSTI)

In this thesis, we begin by studying selected fluctuation observables in order to locate the QCD critical point in heavy-ion collision experiments. In particular, we look at the non-monotonic behavior as a function of the ...

Athanasiou, Christiana

2011-01-01T23:59:59.000Z

188

Third moments of conserved charges in QCD phase diagram  

E-Print Network (OSTI)

We point out that the third moments of conserved charges, the baryon and electric charge numbers, and energy, as well as their mixed moments, change their signs around the QCD phase boundary in the temperature and baryon chemical potential plane. These signs can be measured in relativistic heavy ion collisions, and will give clear information on the phase structure of QCD and the state of the system in the early stage of relativistic heavy ion collisions. The behaviors of these moments on the temperature axis and at small quark chemical potential can be analyzed in lattice QCD simulations. We emphasize that the third moments obtained on the lattice, together with the experimental results, will provide a deep understanding about the QCD phase diagram and the location of the state created in heavy ion collisions.

Kitazawa, Masakiyo; Ejiri, Shinji

2009-01-01T23:59:59.000Z

189

Dual Superconductivity and Chiral Symmetry in Full QCD  

E-Print Network (OSTI)

A disorder parameter detecting dual superconductivity of the vacuum is measured across the chiral phase transition in full QCD with two flavours of dynamical staggered fermions. The observed behaviour is similar to the quenched case.

J. M. Carmona; M. D'Elia; L. Del Debbio; A. Di Giacomo; B. Lucini; G. Paffuti

2001-10-12T23:59:59.000Z

190

QCD effects in Higgs boson production at hadron colliders  

E-Print Network (OSTI)

We present updated predictions for Higgs boson production at the Tevatron and the LHC and we review their corresponding uncertainties. We report on a study of the impact of QCD radiative corrections on the Higgs boson search at the Tevatron.

M. Grazzini

2010-01-21T23:59:59.000Z

191

Transverse momentum dependent quark densities from Lattice QCD  

E-Print Network (OSTI)

We study transverse momentum dependent parton distribution functions (TMDs) with non?local operators in lattice QCD, using MILC?LHPC lattices. We discuss the basic concepts of the method, including renormalization of the ...

Musch, B. U.

192

Exploring quark transverse momentum distributions with lattice QCD  

E-Print Network (OSTI)

We discuss in detail a method to study transverse momentum dependent parton distribution functions (TMDs) using lattice QCD. To develop the formalism and to obtain first numerical results, we directly implement a bilocal ...

Musch, B. U.

193

Molecular States with Hidden Charm and Strange in QCD Sum Rules  

E-Print Network (OSTI)

This work uses the QCD Sum Rules to study the masses of the $D_s \\bar{D}_s^*$ and $D_s^* \\bar{D}_s^*$ molecular states with quantum numbers $J^{PC} = 1^{+-}$. Interpolating currents with definite charge parity are employed, and the contributions up to dimension eight in the Operator Product Expansion (OPE) are taken into account. The results indicate that two hidden strange charmonium-like states may exist in the energy ranges of $3.83 \\sim 4.13 \\; \\text{GeV}$ and $3.99 \\sim 4.31 \\; \\text{GeV}$. The hidden strange charmonium-like states predicted in this work may be accessible through at future experiments, e.g. BESIII, BelleII and SuperB. Possible decay modes, are predicted which may be useful in further research.

Qiao, Cong-Feng

2013-01-01T23:59:59.000Z

194

Thermodynamics of QCD at large quark chemical potential  

E-Print Network (OSTI)

We review the existing weak-coupling results on the thermodynamic potential of deconfined QCD at small and large quark chemical potential and compare with results from lattice gauge theory as well as the exactly solvable case of large-N_f QCD. We also discuss the new analytical results on non-Fermi-liquid effects in entropy and specific heat as well as in dispersion laws of quark quasiparticles at large quark chemical potential.

Andreas Gerhold; Andreas Ipp; Anton Rebhan

2005-12-21T23:59:59.000Z

195

Charm and bottom hadronic form factors with QCD sum rules  

Science Conference Proceedings (OSTI)

We present a brief review of some calculations of form factors and coupling constants in vertices with charm and bottom mesons in the framework of QCD sum rules. We first discuss the motivation for this work, describing possible applications of these form factors to charm and bottom decays processes. We first make a summarize of the QCD sum rules method. We give special attention to the uncertainties of the method introducing by the intrinsic variation of the parameters. Finally we conclude.

Bracco, M. E. [Faculdade de Tecnologia, Universidade do Estado do Rio de Janeiro, Rod. Presidente Dutra Km 298, Polo Industrial, 27537-000, Resende, RJ (Brazil); Rodrigues, B. O.; Cerqueira, A. Jr. [Instituto de Fisica, Universidade do Estado do Rio de Janeiro, Rua Sao Francisco Xavier 524, 20550-900, Rio de Janeiro, RJ (Brazil)

2013-03-25T23:59:59.000Z

196

A New Mass Formula for NG Bosons in QCD  

E-Print Network (OSTI)

An often used mass formula for Nambu-Goldstone (NG) bosons in QCD, such as the pions, involves the condensate $$, $f_{\\pi}$ and the quark current masses. We argue, within the context of the Global Colour Model to QCD, that this expression is wrong. Analysis of the interplay between the Dyson-Schwinger equation for the constituent quark effect and the Bethe-Salpeter equation for the NG boson results in a new mass formula.

Reginald T. Cahill; Susan M. Gunner

1995-07-10T23:59:59.000Z

197

Transverse structure of the QCD string  

Science Conference Proceedings (OSTI)

The characterization of the transverse structure of the QCD string is discussed. We formulate a conjecture as to how the stress-energy tensor of the underlying gauge theory couples to the string degrees of freedom. A consequence of the conjecture is that the energy density and the longitudinal-stress operators measure the distribution of the transverse position of the string, to leading order in the string fluctuations, whereas the transverse-stress operator does not. We interpret recent numerical measurements of the transverse size of the confining string and show that the difference of the energy and longitudinal-stress operators is a particularly natural probe at next-to-leading order. Second, we derive the constraints imposed by open-closed string duality on the transverse structure of the string. We show that a total of three independent ''gravitational'' form factors characterize the transverse profile of the closed string, and obtain the interpretation of recent effective string theory calculations: the square radius of a closed string of length {beta} defined from the slope of its gravitational form factor, is given by (d-1/2{pi}{sigma})log({beta}/4r{sub 0}) in d space dimensions. This is to be compared with the well-known result that the width of the open string at midpoint grows as (d-1/2{pi}{sigma})log(r/r{sub 0}). We also obtain predictions for transition form factors among closed-string states.

Meyer, Harvey B. [Johannes Gutenberg Universitaet Mainz, Institut fuer Kernphysik, 55099 Mainz (Germany)

2010-11-15T23:59:59.000Z

198

Spin-string interaction in QCD strings  

Science Conference Proceedings (OSTI)

I consider the question of the interaction between a QCD string and the spin of a quark or an antiquark on whose worldline the string terminates. The problem is analyzed from the point of view of a string representation for the expectation value of a Wilson loop for a spin-half particle. A string representation of the super Wilson loop is obtained starting from an effective string representation of a Wilson Loop. The action obtained in this manner is invariant under a worldline supersymmetry and has a boundary term which contains the spin-string interaction. For rectangular loops the spin-string interaction vanishes and there is no spin-spin term in the resulting heavy quark potential. On the other hand if an allowance is made for the finite intrinsic thickness of the flux tube by assuming that the spin-string interaction takes place not just at the boundary of the string world sheet but extends to a distance of the order of the intrinsic thickness of the flux tube then we do obtain a spin-spin interaction which falls as the fifth power of the distance. Such a term was previously suggested by Kogut and Parisi in the context of a flux-tube model of confinement.

Vyas, Vikram [Physics Department St. Stephen's College, Delhi University, Delhi (India)

2008-08-15T23:59:59.000Z

199

Quantum Thermodynamics  

E-Print Network (OSTI)

Quantum thermodynamics addresses the emergence of thermodynamical laws from quantum mechanics. The link is based on the intimate connection of quantum thermodynamics with the theory of open quantum systems. Quantum mechanics inserts dynamics into thermodynamics giving a sound foundation to finite-time-thermodynamics. The emergence of the 0-law I-law II-law and III-law of thermodynamics from quantum considerations is presented. The emphasis is on consistence between the two theories which address the same subject from different foundations. We claim that inconsistency is the result of faulty analysis pointing to flaws in approximations.

Ronnie Kosloff

2013-05-10T23:59:59.000Z

200

Duality in quantum field theory (and string theory)  

Science Conference Proceedings (OSTI)

These lectures give an introduction to duality in Quantum Field Theory. We discuss the phases of gauge theories and the implications of the electric-magnetic duality transformation to describe the mechanism of confinement. We review the exact results of N=1 supersymmetric QCD and the Seiberg-Witten solution of N=2 super Yang-Mills. Some of its extensions to String Theory are also briefly discussed.

Luis Álvarez-Gaumé; Frederic Zamora

1998-01-01T23:59:59.000Z

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


201

Dilepton Spectroscopy of QCD Matter at Collider Energies  

E-Print Network (OSTI)

Low-mass dilepton spectra as measured in high-energy heavy-ion collisions are a unique tool to obtain spectroscopic information about the strongly interacting medium produced in these reactions. Specifically, in-medium modifications of the vector spectral function, which is well known in the vacuum, can be deduced from the thermal radiation off the expanding QCD fireball. This, in particular, allows to investigate the fate of the $\\rho$ resonance in the dense medium, and possibly infer from it signatures of the (partial) restoration of chiral symmetry, which is spontaneously broken in the QCD vacuum. After briefly reviewing calculations of thermal dilepton emission rates from hot QCD matter, utilizing effective hadronic theory, lattice QCD or resummed perturbative QCD, we focus on applications to dilepton spectra at heavy-ion collider experiments at RHIC and LHC. This includes invariant-mass spectra at full RHIC energy with transverse-momentum dependencies and azimuthal asymmetries, as well as a systematic investigation of the excitation function down to fixed-target energies, thus making contact to previous precision measurements at the SPS. Furthermore, predictions for the energy frontier at the LHC are presented in both dielectron and dimuon channels.

Ralf Rapp

2013-04-08T23:59:59.000Z

202

Quantum Histories and Quantum Gravity  

E-Print Network (OSTI)

This paper reviews the histories approach to quantum mechanics. This discussion is then applied to theories of quantum gravity. It is argued that some of the quantum histories must approximate (in a suitable sense) to classical histories, if the correct classical regime is to be recovered. This observation has significance for the formulation of new theories (such as quantum gravity theories) as it puts a constraint on the kinematics, if the quantum/classical correspondence principle is to be preserved. Consequences for quantum gravity, particularly for Lorentz symmetry and the idea of "emergent geometry", are discussed.

Joe Henson

2009-01-26T23:59:59.000Z

203

Simulation of the Lattice QCD and Technological Trends in Computation  

E-Print Network (OSTI)

Simulation of Lattice QCD is a challenging computational problem. Currently, technological trends in computation show multiple divergent models of computation. We are witnessing homogeneous multi-core architectures, the use of accelerator on-chip or off-chip, in addition to the traditional architectural models. On the verge of this technological abundance, assessing the performance trade-offs of computing nodes based on these technologies is of crucial importance to many scientific computing applications. In this study, we focus on assessing the efficiency and the performance expected for the Lattice QCD problem on representative architectures and we project the expected improvement on these architectures and their impact on performance for Lattice QCD. We additionally try to pinpoint the limiting factors for performance on these architectures.

K. Ibrahim; J. Jaeger; Z. Liu; L. N. Pouchet; P. Lesnicki; L. Djoudi; D. Barthou; F. Bodin; C. Eisenbeis; G. Grosdidier; O. Pene; P. Roudeau

2008-08-04T23:59:59.000Z

204

Revisiting $K?$ puzzle in the pQCD factorization approach  

E-Print Network (OSTI)

In this paper, we calculated the branching ratios and direct CP violation of the four $B\\to K\\pi$ decays with the inclusion of all currently known next-to-leading order (NLO) contributions by employing the perturbative QCD (pQCD) factorization approach. We found that (a) Besides the 10% enhancement from the NLO vertex corrections, the quark-loops and magnetic penguins, the NLO contributions to the form factors can provide an additional $\\sim 15%$ enhancement to the branching ratios, and lead to a very good agreement with the data; (b) The NLO pQCD predictions are $\\acp^{dir}(B^0\\to K^+\\pi^-)=(-6.5\\pm 3.1)%$ and $\\acp^{dir}(B^+\\to K^+ \\pi^0)=(2.2\\pm 2.0)%$, become well consistent with the data due to the inclusion of the NLO contributions.

Wei Bai; Min Liu; Ying-Ying Fan; Wen-Fei Wang; Shan Cheng; Zhen-Jun Xiao

2013-05-27T23:59:59.000Z

205

Report of the Snowmass 2013 energy frontier QCD working group  

E-Print Network (OSTI)

This is the summary report of the energy frontier QCD working group prepared for Snowmass 2013. We review the status of tools, both theoretical and experimental, for understanding the strong interactions at colliders. We attempt to prioritize important directions that future developments should take. Most of the efforts of the QCD working group concentrate on proton-proton colliders, at 14 TeV as planned for the next run of the LHC, and for 33 and 100 TeV, possible energies of the colliders that will be necessary to carry on the physics program started at 14 TeV. We also examine QCD predictions and measurements at lepton-lepton and lepton-hadron colliders, and in particular their ability to improve our knowledge of strong coupling constant and parton distribution functions.

J. M. Campbell; K. Hatakeyama; J. Huston; F. Petriello; J. Andersen; L. Barze; H. Beauchemin; T. Becher; M. Begel; A. Blondel; G. Bodwin; R. Boughezal; S. Carrazza; M. Chiesa; G. Dissertori; S. Dittmaier; G. Ferrera; S. Forte; N. Glover; T. Hapola; A. Huss; X. Garcia i Tormo; M. Grazzini; S. Hoche; P. Janot; T. Kasprzik; M. Klein; U. Klein; D. Kosower; Y. Li; X. Liu; P. Mackenzie; D. Maitre; E. Meoni; K. Mishra; G. Montagna; M. Moretti; P. Nadolsky; O. Nicrosini; F. Piccinini; L. Reina; V. Radescu; J. Rojo; J. Russ; S. Sapeta; A. Schwartzman; P. Skands; J. Smillie; I. W. Stewart; F. J. Tackmann; F. Tramontano; R. Van de Water; J. R. Walsh; S. Zuberi

2013-10-19T23:59:59.000Z

206

B Mixing in the Standard Model and Beyond: Lattice QCD  

SciTech Connect

We give a brief overview and progress report on our lattice QCD calculation of neutral B mixing hadronic matrix elements needed for Standard Model and Beyond the Standard Model physics. Reference [1] contains more details and results. We have a good start on a large-data-set lattice QCD calculation of the matrix elements that describe neutral-B mixing. Our calculation will cover the operators needed for both Standard Model and Beyond the Standard Model physics. For the Standard Model matrix elements, we expect to halve the error on current, published calculations. In the Beyond the Standard Model case, this will be the first full-QCD (unquenched) calculation and the first update in ten years.

Bernard, C.; /Washington U., St. Louis; Bouchard, C.M.; /Illinois U., Urbana /Fermilab; El-Khadra, A.X.; /Illinois U., Urbana; Freeland, E.D.; /Illinois U., Urbana /Benedictine U.; Gamiz, E.; /Fermilab /Granada U., Theor. Phys. Astrophys. /CAFPE, Granada; Kronfeld, A.S.; /Fermilab; Laiho, J.; /Glasgow U.; Van de Water, R.S.; /Brookhaven

2011-11-01T23:59:59.000Z

207

Search for the S=+1 pentaquarks in quenched lattice QCD  

E-Print Network (OSTI)

We study spin $\\frac12$ hadronic states in quenched lattice QCD to search for a possible $S=+1$ pentaquark resonance. Our work is the first systematic lattice QCD study which properly carries out the following analyses: {\\it (1) the careful extraction of the first two low energy states with very high statistics and the variational method} and {\\it (2) the study of volume dependences of eigenenergies and spectral weights to distinguish resonance states from scattering states}. Simulations are carried out on $8^3\\times 24$, $10^3\\times 24$, $12^3\\times 24$ and $16^3\\times 24$ lattices at $\\beta$=5.7 with the standard plaquette gauge action and the Wilson quark action. Our result indicates the existence of a resonance state lying slightly above the NK threshold in $(I,J^P)=(0,\\frac12^-)$ channel in quenched QCD.

Toru T. Takahashi; Takashi Umeda; Tetsuya Onogi; Teiji Kunihiro

2005-09-27T23:59:59.000Z

208

Search for the pentaquark resonance signature in lattice QCD  

E-Print Network (OSTI)

Claims concerning the possible discovery of the \\Theta^+ pentaquark, with minimal quark content uudd\\bar{s}, have motivated our comprehensive study into possible pentaquark states using lattice QCD. We review various pentaquark interpolating fields in the literature and create a new candidate ideal for lattice QCD simulations. Using these interpolating fields we attempt to isolate a signal for a five-quark resonance. Calculations are performed using improved actions on a large 20^3 x 40 lattice in the quenched approximation. The standard lattice resonance signal of increasing attraction between baryon constituents for increasing quark mass is not observed for spin-1/2 pentaquark states. We conclude that evidence supporting the existence of a spin-1/2 pentaquark resonance does not exist in quenched QCD.

B. G. Lasscock; J. Hedditch; D. B. Leinweber; W. Melnitchouk; A. W. Thomas; A. G. Williams; R. D. Young; J. M. Zanotti

2005-03-10T23:59:59.000Z

209

Inverse Problems in Classical and Quantum Physics  

E-Print Network (OSTI)

The subject of this thesis is in the area of Applied Mathematics known as Inverse Problems. Inverse problems are those where a set of measured data is analysed in order to get as much information as possible on a model which is assumed to represent a system in the real world. We study two inverse problems in the fields of classical and quantum physics: QCD condensates from tau-decay data and the inverse conductivity problem. We use a functional method which allows us to extract within rather general assumptions phenomenological parameters of QCD (the condensates) from a comparison of the time-like experimental data with asymptotic space-like results from theory. The price to be paid for the generality of assumptions is relatively large errors in the values of the extracted parameters. Although we do not claim that our method is superior to other approaches, we hope that our results lend additional confidence to the numerical results obtained with the help of methods based on QCD sum rules. In this thesis, als...

Almasy, Andrea A

2009-01-01T23:59:59.000Z

210

Quantum Information Portal  

Science Conference Proceedings (OSTI)

... Quantum Devices; Quantum Information Technology; Quantum Key Distribution; ... Entangled photon generation in a phase-modulated, quasi ...

2013-10-23T23:59:59.000Z

211

Quantum bundles and quantum interactions  

E-Print Network (OSTI)

A geometric framework for describing quantum particles on a possibly curved background is proposed. Natural constructions on certain distributional bundles (`quantum bundles') over the spacetime manifold yield a quantum ``formalism'' along any 1-dimensional timelike submanifold (a `detector'); in the flat, inertial case this turns out to reproduce the basic results of the usual quantum field theory, while in general it could be seen as a local, ``linearized'' description of the actual physics.

Daniel Canarutto

2005-06-22T23:59:59.000Z

212

A Stable Magnetic Background in SU(2) QCD  

E-Print Network (OSTI)

Motivated by the instability of the Savvidy-Nielsen-Olesen (SNO) vacuum we make a systematic search for a stable magnetic background in pure SU(2) QCD. It is shown that Wu-Yang monopole-antimonopole pair is unstable under vacuum fluctuations. However, it is shown that a pair of axially symmetric monopole-antimonopole string configuration is stable, provided the distance between the two strings is small enough (less than a critical value). The existence of a stable monopole-antimonopole string background strongly supports that a magnetic condensation of monopole-antimonopole pairs can indeed generate a dynamical symmetry breaking, and thus a desired magnetic confinement of color, in QCD.

Y. M. Cho; D. G. Pak

2005-10-24T23:59:59.000Z

213

Nuclear Energy Density Functionals Constrained by Low-Energy QCD  

E-Print Network (OSTI)

A microscopic framework of nuclear energy density functionals is reviewed, which establishes a direct relation between low-energy QCD and nuclear structure, synthesizing effective field theory methods and principles of density functional theory. Guided by two closely related features of QCD in the low-energy limit: a) in-medium changes of vacuum condensates, and b) spontaneous breaking of chiral symmetry; a relativistic energy density functional is developed and applied in studies of ground-state properties of spherical and deformed nuclei.

Vretenar, Dario

2008-01-01T23:59:59.000Z

214

Nuclear Energy Density Functionals Constrained by Low-Energy QCD  

E-Print Network (OSTI)

A microscopic framework of nuclear energy density functionals is reviewed, which establishes a direct relation between low-energy QCD and nuclear structure, synthesizing effective field theory methods and principles of density functional theory. Guided by two closely related features of QCD in the low-energy limit: a) in-medium changes of vacuum condensates, and b) spontaneous breaking of chiral symmetry; a relativistic energy density functional is developed and applied in studies of ground-state properties of spherical and deformed nuclei.

Dario Vretenar

2008-02-06T23:59:59.000Z

215

New insight on global QCD fits using Regge theory  

SciTech Connect

In global QCD fits, one has to choose an initial parton distribution at Q{sup 2} = Q{sub 0}{sup 2}. I shall argue that the initial condition chosen in usual standard sets is inconsistent with analytic S-matrix theory. I shall show how one can combine these two approaches, leading to a Regge-compatible next-to-leading order global QCD fit. This allows one to extend the parametrisation in the low-Q2 region. Finally, I shall discuss how it it possible to use the Dokshitzer-Gribov-Lipatov-Altarelli-Parisi (DGLAP) equation to obtain information on Regge models at high Q2.

Soyez, G. [CEA Saclay, Service de Physique Theorique, Orme des Merisiers Bat 774, F-91191 Gif-Sur-Yvette (France)

2005-06-14T23:59:59.000Z

216

Chiral magnetic effect in lattice QCD with chiral chemical potential  

E-Print Network (OSTI)

We perform a first lattice QCD simulation including two-flavor dynamical fermion with chiral chemical potential. Because the chiral chemical potential gives rise to no sign problem, we can exactly analyze a chirally asymmetric QCD matter by the Monte Carlo simulation. By applying an external magnetic field to this system, we obtain a finite induced current along the magnetic field, which corresponds to the chiral magnetic effect. The obtained induced current is proportional to the magnetic field and to the chiral chemical potential, which is consistent with an analytical prediction.

Yamamoto, Arata

2011-01-01T23:59:59.000Z

217

The Heisenberg XX spin chain and low-energy QCD  

E-Print Network (OSTI)

By using random matrix models we uncover a connection between the low energy sector of four dimensional QCD at finite volume and the Heisenberg XX model in a 1d spin chain. This connection allows to relate crucial properties of QCD with physically meaningful properties of the spin chain, establishing a dictionary between both worlds. We predict for the spin chain a third-order phase transition and a Tracy-Widom law in the transition region. We postulate that this dictionary goes beyond the particular example analyzed here and can be applied to other QFT and spin chain models.

David Pérez-García; Miguel Tierz

2013-05-16T23:59:59.000Z

218

Higgs Boson Production at Hadron Colliders in NNLO QCD  

SciTech Connect

We compute the total cross-section for direct Higgs boson production in hadron collisions at NNLO in perturbative QCD. A new technique which allows us to perform an algorithmic evaluation of inclusive phase-space integrals is introduced, based on the Cutkosky rules, integration by parts and the differential equation method for computing master integrals. Finally, we discuss the numerical impact of the {Omicron}({alpha}{sub s}{sup 2}) QCD corrections to the Higgs boson production cross-section at the LHC and the Tevatron.

Anastasiou, Charalampos

2002-08-08T23:59:59.000Z

219

Quantum Cosmology  

E-Print Network (OSTI)

We give an introduction into quantum cosmology with emphasis on its conceptual parts. After a general motivation we review the formalism of canonical quantum gravity on which discussions of quantum cosmology are usually based. We then present the minisuperspace Wheeler--DeWitt equation and elaborate on the problem of time, the imposition of boundary conditions, the semiclassical approximation, the origin of irreversibility, and singularity avoidance. Restriction is made to quantum geometrodynamics; loop quantum gravity and string theory are discussed in other contributions to this volume.

Claus Kiefer; Barbara Sandhoefer

2008-04-04T23:59:59.000Z

220

Lattice QCD Thermodynamics First 5000 Trajectories  

Science Conference Proceedings (OSTI)

These results represent the first LQCD analysis for approximately 5000 trajectories with each of the p4rhmc and milc codes, with some of the lower temperature runs having fewer. Both runs were for lattice dimensions of 32{sup 3}x8. Some 32{sup 4} T=0 jobs were also run for p4rhmc. The p4 calculation was performed with v2.0 QMP{_}MPI.X (semi-optimized p4 code using qmp over mpi) and milc version of the su3 rhmc susc eos executable dated Mar 1, 2007 on ubgl in the /usr/gapps/hip/qcd/milc/bin subdirectory (svn revision 28). As with previous runs, calculations were performed along lines of constant physics, with the light quark masses 2-3 times their physics values and the strange quark mass set by m{sub ud} = 0.1m{sub s}. Job submissions were performed using a new subSet.pl job submission script that locates current jobs and submits additional jobs with the same beta value as pending. Note that after reaching a limit of about 35 jobs subsequent submissions are delayed and will not be submitted directly from that state. The job submission script was used to submit revised versions of the milc and p4rhmc csh scripts. Initial thermalized lattices for each code were also for milc (taken from the firstPhys runs), but the p4rhmc runs include thermalization. The only modifications for running on BG/L were to the directory names and the mT parameter which determines job durations (24 hrs on BG/L vs. 4 hrs on ubgl). All finite temperature jobs were submitted to the 512 node partitions, and all T=0 runs were submitted to 2048 node partitions. The set of runs was plagued by filesystem errors on lscratch1 and lscratcH{sub 2}. Many jobs had to be reset (deleting the most recent output file for milc and/or lattice for p4) and resubmitted. The analysis was performed with a new set of scripts that produced a more condensed output for scanning. All scans were verified with checksums, which have been retained in the output along with the line numbers. All lattices, log files, and job submission scripts have been archived to permanent storage in the 5k subdirectory for subsequent analysis.

Soltz, R; Gupta, R

2007-03-15T23:59:59.000Z

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


221

Quantum chaos in elementary quantum mechanics  

E-Print Network (OSTI)

chaos in elementary quantum mechanics so-called integrableIntroduction to Quantum Mechanics (Englewoods Cliff, NJ:Lifshitz E M 1977 Quantum Mechanics (New York: Pergamon) [

Dabaghian, Yuri A; Jensen, R

2005-01-01T23:59:59.000Z

222

From quantum graphs to quantum random walks  

E-Print Network (OSTI)

We give a short overview over recent developments on quantum graphs and outline the connection between general quantum graphs and so-called quantum random walks.

Gregor Tanner

2005-04-29T23:59:59.000Z

223

Singlet Free Energies and Renormalized Polyakov Loop in full QCD  

E-Print Network (OSTI)

We calculate the free energy of a static quark anti-quark pair and the renormalized Polyakov loop in 2+1- and 3- flavor QCD using $16^3 \\times 4$ and $16^3 \\times 6$ lattices and improved staggered p4 action. We also compare the renormalized Polyakov loop with the results of our earlier studies.

K. Petrov

2006-10-05T23:59:59.000Z

224

QCD IN A FINITE VOLUME PIERRE VAN BAAL  

E-Print Network (OSTI)

to a handbook of QCD, in honor of Boris Lazarevich Io#e, to bring together results and methods that were copies is called a fundamental domain for non­abelian gauge theories. 5 3 #12; Having arranged the low that the boundary of the fundamental domain, unlike its interior, has gauge copies that implement the non

van Baal, Pierre

225

Quark masses from lattice QCD and the study of textures  

E-Print Network (OSTI)

I review how the determination of quark masses from lattice QCD can be used to study textures in quark mass matrices. This type of theory relates quark masses to CKM matrix elements. I demonstrate how the recent precision results from the HPQCD and MILC collaborations for quark masses can be used to test some of these ideas.

Craig McNeile

2010-04-28T23:59:59.000Z

226

An estimate of the chiral condensate from unquenched lattice QCD  

E-Print Network (OSTI)

Using the parameters in the chiral Lagrangian obtained by MILC from their unquenched lattice QCD calculations with 2+1 flavours of sea quarks, I estimate (2 GeV)/n_f = -(259 \\pm 27 MeV)**3 in the MS_bar scheme. I compare this value to other determinations.

Craig McNeile

2005-04-08T23:59:59.000Z

227

Microscopic eigenvalue correlations in QCD with imaginary isospin chemical potential  

E-Print Network (OSTI)

We consider the chiral limit of QCD subjected to an imaginary isospin chemical potential. In the epsilon-regime of the theory we can perform precise analytical calculations based on the zero-momentum Goldstone modes in the low-energy effective theory. We present results for the spectral correlation functions of the associated Dirac operators.

P. H. Damgaard; U. M. Heller; K. Splittorff; B. Svetitsky; D. Toublan

2006-04-07T23:59:59.000Z

228

Small Quarkonium states in an anisotropic QCD plasma  

E-Print Network (OSTI)

We determine the hard-loop resummed propagator in an anisotropic QCD plasma in general covariant gauges and define a potential between heavy quarks from the Fourier transform of its static limit. We find that the potential exhibits angular dependence and that binding of very small quarkonium states is stronger than in an isotropic plasma.

Yun Guo

2008-05-16T23:59:59.000Z

229

Static-light meson masses from twisted mass lattice QCD  

E-Print Network (OSTI)

We compute the static-light meson spectrum using two-flavor Wilson twisted mass lattice QCD. We have considered five different values for the light quark mass corresponding to 300 MeV < m_PS < 600 MeV. We have extrapolated our results, to make predictions regarding the spectrum of B and B_s mesons.

ETM Collaboration; Karl Jansen; Chris Michael; Andrea Shindler; Marc Wagner

2008-08-15T23:59:59.000Z

230

Nucleon Form Factors and Hidden Symmetry in Holographic QCD  

E-Print Network (OSTI)

The vector dominance of the electromagnetic form factors both for mesons and baryons arises naturally in holographic QCD, where both the number of colors and the 't Hooft coupling are taken to be very large, offering a bona-fide derivation of the notion of vector dominance. The crucial ingredient for this is the infinite tower of vector mesons in the approximations made which share features that are characteristic of the quenched approximation in lattice QCD. We approximate the infinite sum by contributions from the lowest four vector mesons of the tower which turn out to saturate the charge and magnetic moment sum rules within a few percent and compute them totally free of unknown parameters for momentum transfers Q^2 less than 1GeV^2. We identify certain observables that can be reliably computed within the approximations and others that are not, and discuss how the improvement of the latter can enable one to bring holographic QCD closer to QCD proper.

Deog Ki Hong; Mannque Rho; Ho-Ung Yee; Piljin Yi

2007-10-25T23:59:59.000Z

231

Nucleon form factors and hidden symmetry in holographic QCD  

Science Conference Proceedings (OSTI)

The vector dominance of the electromagnetic form factors both for mesons and baryons arises naturally in holographic QCD, where both the number of colors and the 't Hooft coupling are taken to be very large, offering a bona-fide derivation of the notion of vector dominance. The crucial ingredient for this is the infinite tower of vector mesons in the approximations made which share features that are characteristic of the quenched approximation in lattice QCD. We approximate the infinite sum by contributions from the lowest four vector mesons of the tower which turn out to saturate the charge and magnetic moment sum rules within a few percent and compute them totally free of unknown parameters for momentum transfers Q{sup 2} < or approx. 1 GeV{sup 2}. We identify certain observables that can be reliably computed within the approximations and others that are not, and discuss how the improvement of the latter can enable one to bring holographic QCD closer to QCD proper.

Hong, Deog Ki [Department of Physics, Pusan National University, Busan 609-735 (Korea, Republic of); Rho, Mannque [Service de Physique Theorique, CEA Saclay, 91191 Gif-sur-Yvette (France); Yee, Ho-Ung [School of Physics, Korea Institute for Advanced Study, Seoul 130-722 (Korea, Republic of); Abdus Salam International Centre for Theoretical Physics, Strada Costiera 11, 34014, Trieste (Italy); Yi, Piljin [School of Physics, Korea Institute for Advanced Study, Seoul 130-722 (Korea, Republic of)

2008-01-01T23:59:59.000Z

232

Quantum Communications  

Science Conference Proceedings (OSTI)

... In summary, we perform research and development (R&D) in quantum communication and related measurement areas with an emphasis on ...

2013-07-24T23:59:59.000Z

233

Quantum Electrical Measurements Portal  

Science Conference Proceedings (OSTI)

NIST Home > Quantum Electrical Measurements Portal. Quantum Electrical Measurements Portal. Subject Areas. Electrical ...

2013-03-21T23:59:59.000Z

234

Quantum Networks for Generating Arbitrary Quantum States  

E-Print Network (OSTI)

Quantum protocols often require the generation of specific quantum states. We describe a quantum algorithm for generating any prescribed quantum state. For an important subclass of states, including pure symmetric states, this algorithm is efficient.

Phillip Kaye; Michele Mosca

2004-07-14T23:59:59.000Z

235

The theta^+ baryon in soliton models: large Nc QCD and the validity of rigid-rotor quantization  

E-Print Network (OSTI)

A light collective theta+ baryon state (with strangeness +1) was predicted via rigid-rotor collective quantization of SU(3) chiral soliton models. This paper explores the validity of this treatment. A number of rather general analyses suggest that predictions of exotic baryon properties based on this approximation do not follow from large Nc QCD. These include an analysis of the baryon's width, a comparison of the predictions with general large Nc consistency conditions of the Gervais-Sakita-Dashen-Manohar type; an application of the technique to QCD in the limit where the quarks are heavy; a comparison of this method with the vibration approach of Callan and Klebanov; and the 1/Nc scaling of the excitation energy. It is suggested that the origin of the problem lies in an implicit assumption in the that the collective motion is orthogonal to vibrational motion. While true for non-exotic motion, the Wess-Zumino term induces mixing at leading order between collective and vibrational motion with exotic quantum numbers. This suggests that successful phenomenological predictions of theta+ properties based on rigid-rotor quantization were accidental.

Thomas D. Cohen

2003-12-15T23:59:59.000Z

236

Quantum Conductance Project/Graphene-Based Quantum ...  

Science Conference Proceedings (OSTI)

Quantum Conductance Project/Graphene-Based Quantum Metrology. Summary: ... Graphene Hall bar developed at NIST by undergraduate students. ...

2011-10-03T23:59:59.000Z

237

Gaussian quantum information  

E-Print Network (OSTI)

The science of quantum information has arisen over the last two decades centered on the manipulation of individual quanta of information, known as quantum bits or qubits. Quantum computers, quantum cryptography, and quantum ...

Weedbrook, Christian

238

QCD Phase Diagram According to the Center Group  

SciTech Connect

We study an effective theory for QCD at finite temperature and density which contains the leading center symmetric and center symmetry breaking terms. The effective theory is studied in a flux representation where the complex phase problem is absent and the model becomes accessible to Monte Carlo techniques also at finite chemical potential. We simulate the system by using a generalized Prokof'ev-Svistunov worm algorithm and compare the results to a low temperature expansion. The phase diagram is determined as a function of temperature, chemical potential, and quark mass. The shape and quark mass dependence of the phase boundaries are as expected for QCD. The transition into the deconfined phase is smooth throughout, without any discontinuities or critical points.

Delgado Mercado, Ydalia; Gattringer, Christof [Institut fuer Physik, Karl-Franzens Universitaet, Graz (Austria); Evertz, Hans Gerd [Institute for Theoretical and Computational Physics, Technische Universitaet Graz (Austria)

2011-06-03T23:59:59.000Z

239

On the QCD phase diagram at finite chemical potential  

SciTech Connect

We present results for the phase diagram of QCD with two massless quark flavours as obtained from a first-principles functional renormalisation group approach. In particular we compute order parameters for chiral symmetry breaking and quark confinement at vanishing and non-zero imaginary chemical potential. Our analytical and numerical results suggest a close relation between the chiral and the deconfinement phase transition. We discuss the properties of dual order parameters at imaginary and real chemical potential.

Haas, Lisa M.; Pawlowski, Jan M. [Institut fuer Theoretische Physik, Universitaet Heidelberg, Philosophenweg 16, 69120 Heidelberg (Germany); ExtreMe Matter Institute EMMI, GSI, Planckstr. 1, 64291 Darmstadt (Germany); Braun, Jens [Theoretisch-Physikalisches Institut, Universitaet Jena, Max-Wien-Platz 1, 07743 Jena (Germany)

2011-05-23T23:59:59.000Z

240

A QCD Sum Rules Approach to Mixing of Hadrons  

Science Conference Proceedings (OSTI)

A method for the calculation of the hadronic mixing angles using QCD sum rules is proposed. This method is then applied to predict the mixing angle between the heavy cascade hyperons {Xi}{sub Q} and {Xi}{sub Q}{sup '} where Q = c or Q = b. It is obtained the {theta}{sub b} = 6.4 deg. {+-}1.8 deg. and {theta}{sub c} = 5.5 deg. {+-}1.8 deg.

Aliev, T. M. [Physics Department, Middle East Technical University, Ankara (Turkey); Permanent institute: Institute of Physics, Baku (Azerbaijan); Ozpineci, A. [Physics Department, Middle East Technical University, Ankara (Turkey); Zamiralov, V. S. [Institute of Nuclear Physics, M. V. Lomonosov MSU, Moscow (Russian Federation)

2010-12-28T23:59:59.000Z

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


241

HYBRIDGEN: A MODEL FOR THE STUDY OF QCD HYBRID STATES.  

DOE Green Energy (OSTI)

We study the mixing of excited states of a Hydrogen atom in a cavity with de-excited states plus a confined photon as a model for the coupling of quark-antiquark and quark-antiquark-gluon hybrid states in QCD. For an interesting range of parameters, the results are analytic. We find a case for which wavefunctions (and hence decay patterns) may be at odds with mass with respect to identification of a state as hybrid or not.

GOLDMAN, J TERRANCE; BRISUDOVA, M M

2002-08-28T23:59:59.000Z

242

QCD sum rule for nucleon in nuclear matter  

E-Print Network (OSTI)

We consider the two-point function of nucleon current in nuclear matter and write a QCD sum rule to analyse the residue of the nucleon pole as a function of nuclear density. The nucleon self-energy needed for the sum rule is taken as input from calculations using phenomenological NN potential. Our result shows a decrease in the residue with increasing nuclear density, as is known to be the case with similar quantities.

S. Mallik; Sourav Sarkar

2009-04-22T23:59:59.000Z

243

Hard thermal effective action in QCD through the thermal operator  

E-Print Network (OSTI)

Through the application of the thermal operator to the zero temperature retarded Green's functions, we derive in a simple way the well known hard thermal effective action in QCD. By relating these functions to forward scattering amplitudes for on-shell particles, this derivation also clarifies the origin of important properties of the hard thermal effective action, such as the manifest Lorentz and gauge invariance of its integrand.

Ashok Das; J. Frenkel

2007-03-08T23:59:59.000Z

244

Excited and exotic charmonium spectroscopy from lattice QCD  

Science Conference Proceedings (OSTI)

We study the charmonium spectrum in full QCD on anisotropic lattices generated by Hadron Spectrum Collaboration. We adopt a large basis of interpolating operators to extract the excited charmonium states using the variational method. A detailed spectrum of excited charmonium mesons in many J{sup PC} channels is obtained. Some exotic hybrid states ( with J{sup PC} = 0{sup +-} , 1{sup -+} , 2{sup +-}) are also studied

Liu, L; Peardon, M J; Ryan, S M; Thomas, C; Vilaseca, P; Dudek, J; Edwards, R; Joo, B

2012-12-01T23:59:59.000Z

245

QCD Thermodynamics with an almost realistic quark mass spectrum  

E-Print Network (OSTI)

We will report on the status of a new large scale calculation of thermodynamic quantities in QCD with light up and down quarks corresponding to an almost physical light quark mass value and a heavier strange quark mass. These calculations are currently being performed on the QCDOC Teraflops computers at BNL. We will present new lattice calculations of the transition temperature and various susceptibilities reflecting properties of the chiral transition. All these quantities are of immediate interest for heavy ion phenomenology.

C. Schmidt

2006-01-25T23:59:59.000Z

246

QCD corrections to Higgs boson production: An update  

SciTech Connect

We compute analytic results for the QCD corrections to Higgs boson production in hadronic collisions in the limit in which the top quark is much heavier than the Higgs boson. The first non-leading corrections of O({alpha}{sub s}{sup 2}M{sub H}{sup 2}/m{sub t}{sup 2}) are given and numerical results presented for the LHC.

Dawson, S. [Brookhaven National Lab., Upton, NY (United States); Kauffman, R. [Franklin and Marshall Coll., Lancaster, PA (United States). Physics Dept.

1994-09-01T23:59:59.000Z

247

W ? production in vector boson fusion at NLO in QCD  

E-Print Network (OSTI)

The next-to-leading order QCD corrections to W gamma production in association with two jets via vector boson fusion are calculated, including the leptonic decay of the W with full off-shell effects and spin correlations. The process lends itself to a test of quartic gauge couplings. The next-to-leading order corrections reduce the scale uncertainty significantly and show a non-trivial phase space dependence.

Francisco Campanario; Nicolas Kaiser; Dieter Zeppenfeld

2013-09-27T23:59:59.000Z

248

QCD in terms of gauge-invariant dynamical variables  

E-Print Network (OSTI)

For a complete description of the physical properties of low-energy QCD, it might be advantageous to first reformulate QCD in terms of gauge-invariant dynamical variables, before applying any approximation schemes. Using a canonical transformation of the dynamical variables, which Abelianises the non-Abelian Gauss-law constraints to be implemented, such a reformulation can be achieved for QCD. The exact implementation of the Gauss laws reduces the colored spin-1 gluons and spin-1/2 quarks to unconstrained colorless spin-0, spin-1, spin-2 and spin-3 glueball fields and colorless Rarita-Schwinger fields respectively. The obtained physical Hamiltonian can then be rewritten into a form, which separates the rotational from the scalar degrees of freedom, and admits a systematic strong-coupling expansion in powers of lambda=g^{-2/3}, equivalent to an expansion in the number of spatial derivatives. The leading-order term in this expansion corresponds to non-interacting hybrid-glueballs, whose low-lying masses can be ...

Pavel, Hans-Peter

2013-01-01T23:59:59.000Z

249

Non-perturbative Green's functions and the QCD effective charge  

E-Print Network (OSTI)

Using as ingredients the non-perturbative solutions of various QCD Green's function obtained from Schwinger-Dyson equations (SDEs), we study two versions of the QCD effective charge. The first one obtained from the pinch technique gluon self-energy, and the second from the ghost-gluon vertex. Despite the distinct nature of their buildings blocks, the two effectives charges are almost identical in the entire range of momenta, due to a fundamental identity relating the ghost dressing function with the two form factors of Green's function, which is of central importance in the PT-BFM formalism. In this talk, we outline how to derive this crucial identity from the SDEs of the aforementioned Green's functions. The renormalization procedure that preserves the validity of this identity is discussed in detail. Most importantly, we show that due to the infrared finiteness of the gluon propagator, the QCD charge obtained with either definition freezes in the deep infrared, in agreement with theoretical and phenomenological expectations.

Arlene C. Aguilar

2009-11-23T23:59:59.000Z

250

{rho} meson decay in 2+1 flavor lattice QCD  

SciTech Connect

We perform a lattice QCD study of the {rho} meson decay from the N{sub f}=2+1 full QCD configurations generated with a renormalization group improved gauge action and a nonperturbatively O(a)-improved Wilson fermion action. The resonance parameters, the effective {rho}{yields}{pi}{pi} coupling constant and the resonance mass, are estimated from the P-wave scattering phase shift for the isospin I=1 two-pion system. The finite size formulas are employed to calculate the phase shift from the energy on the lattice. Our calculations are carried out at two quark masses, m{sub {pi}=}410 MeV (m{sub {pi}/}m{sub {rho}=}0.46) and m{sub {pi}=}300 MeV (m{sub {pi}/}m{sub {rho}=}0.35), on a 32{sup 3}x64 (La=2.9 fm) lattice at the lattice spacing a=0.091 fm. We compare our results at these two quark masses with those given in the previous works using N{sub f}=2 full QCD configurations and the experiment.

Aoki, S.; Ishizuka, N.; Taniguchi, Y.; Ukawa, A.; Yoshie, T. [Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8571 (Japan); Center for Computational Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8577 (Japan); Ishikawa, K-I.; Okawa, M. [Department of Physics, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Kanaya, K. [Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8571 (Japan); Kuramashi, Y. [Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8571 (Japan); Center for Computational Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8577 (Japan); RIKEN Advanced Institute for Computational Science, Kobe, Hyogo 650-0047 (Japan); Namekawa, Y.; Ukita, N. [Center for Computational Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8577 (Japan); Yamazaki, T. [Kobayashi-Maskawa Institute for the Origin of Particles and the Universe, Nagoya University, Nagoya, Aichi 464-8602 (Japan)

2011-11-01T23:59:59.000Z

251

Quantum Computational Complexity  

E-Print Network (OSTI)

This article surveys quantum computational complexity, with a focus on three fundamental notions: polynomial-time quantum computations, the efficient verification of quantum proofs, and quantum interactive proof systems. Properties of quantum complexity classes based on these notions, such as BQP, QMA, and QIP, are presented. Other topics in quantum complexity, including quantum advice, space-bounded quantum computation, and bounded-depth quantum circuits, are also discussed.

John Watrous

2008-04-21T23:59:59.000Z

252

Construction of the Dual Ginzburg-Landau Theory from the Lattice QCD  

E-Print Network (OSTI)

We briefly review the QCD physics and then introduce recent topics on the confinement physics. In the maximally abelian (MA) gauge, the low-energy QCD is abelianized owing to the effective off-diagonal gluon mass $M_{\\rm off} \\simeq 1.2 {\\rm GeV}$ induced by the MA gauge fixing. We demonstrate the construction of the dual Ginzburg-Landau (DGL) theory from the low-energy QCD in the MA gauge in terms of the lattice QCD evidences on infrared abelian dominance and infrared monopole condensation.

H. Suganuma; K. Amemiya; H. Ichie; Y. Koma

2004-07-10T23:59:59.000Z

253

Making QCD Lattice Data Accessible and Organized through Advanced Web Interfaces  

E-Print Network (OSTI)

The Gauge Connection at qcd.nersc.gov is one of the most popular repositories of QCD lattice ensembles. It is used to access 16TB of archived QCD data from the High Performance Storage System (HPSS) at the National Energy Research Scientific Computing Center (NERSC). Here, we present a new web interface for qcd.nersc.gov which allows physicists to browse and search the data, as well as download individual files or entire ensembles in batch. Our system distinguishes itself from others because of its ease of use and web based workflow.

Di Pierro, Massimo; Cholia, Shreyas; Skinner, David

2011-01-01T23:59:59.000Z

254

Making QCD Lattice Data Accessible and Organized through Advanced Web Interfaces  

E-Print Network (OSTI)

The Gauge Connection at qcd.nersc.gov is one of the most popular repositories of QCD lattice ensembles. It is used to access 16TB of archived QCD data from the High Performance Storage System (HPSS) at the National Energy Research Scientific Computing Center (NERSC). Here, we present a new web interface for qcd.nersc.gov which allows physicists to browse and search the data, as well as download individual files or entire ensembles in batch. Our system distinguishes itself from others because of its ease of use and web based workflow.

Massimo Di Pierro; James Hetrick; Shreyas Cholia; David Skinner

2011-12-09T23:59:59.000Z

255

Analytic Estimate of the Order Parameter for Monopole Condensation in QCD  

E-Print Network (OSTI)

The disorder parameter $$ for the condensation of monopoles in QCD is estimated analytically in terms of gauge invariant field strength correlators. The continuum limit is discussed.

Adriano Di Giacomo

2006-10-18T23:59:59.000Z

256

Quantum Indeterminacy in Local Measurement of Cosmic Expansion  

E-Print Network (OSTI)

For a system of two small bodies in an expanding universe, bounds on mass and separation are estimated, from standard gravity and quantum mechanics, such that both their gravity and the process of quantum measurement affect their motion less than the cosmic expansion does. It is shown that such a direct local measurement of cosmic expansion or acceleration at rate $H$ is only possible, even in principle, in a region of size greater than $H^{-3/5}$ in Planck units, or about 60 meters in the current universe, a new scale that defines a boundary between quantum and classical expansion. A generalization to spatially extended linear density perturbations shows the same scale. Matching vacuum energy or directional information in localized field states to gravity on this system length scale yields a particle mass scale of $H^{3/10}$, or about 7 GeV today. Possible connections of cosmic acceleration with the QCD vacuum are discussed.

Craig J. Hogan

2013-12-30T23:59:59.000Z

257

Quantum indeterminacy in local measurement of cosmic expansion  

E-Print Network (OSTI)

For a system of two small bodies in an expanding universe, bounds on mass and separation are estimated, from standard gravity and quantum mechanics, such that both their gravity and the process of quantum measurement affect their motion less than the cosmic expansion does. It is shown that such a direct local measurement of cosmic expansion or acceleration at rate $H$ is only possible, even in principle, in a region of size greater than $H^{-3/5}$ in Planck units, or about 60 meters in the current universe, a new scale that defines a boundary between quantum and classical expansion. A generalization to spatially extended linear density perturbations shows the same scale. Matching vacuum energy or directional information in localized field states to gravity on this system length scale yields a particle mass scale of $H^{3/10}$, or about 7 GeV today. Possible connections of cosmic acceleration with the QCD vacuum are discussed.

Hogan, Craig J

2013-01-01T23:59:59.000Z

258

Physicalism versus quantum mechanics  

E-Print Network (OSTI)

Foundations of Quantum Mechanics. (Princeton UniversityMind, Matter, and Quantum Mechanics, (Springer, Berlin & NewMindful Universe: Quantum Mechanics and the Participating

Stapp, Henry P; Theoretical Physics Group; Physics Division

2009-01-01T23:59:59.000Z

259

quarkmodrpp.dvi  

NLE Websites -- All DOE Office Websites (Extended Search)

1 1 by C. Amsler (University of Z¨ urich), T. DeGrand (University of Colorado, Boulder), and B. Krusche (University of Basel). 14.1. Quantum numbers of the quarks Quantum chromodynamics (QCD) is the theory of the strong interactions. QCD is a quantum field theory and its constituents are a set of fermions, the quarks, and gauge bosons, the gluons. Strongly interacting particles, the hadrons, are bound states of quark and gluon fields. As gluons carry no intrinsic quantum numbers beyond color charge, and because color is believed to be permanently confined, most of the quantum numbers of strongly interacting particles are given by the quantum numbers of their constituent quarks and antiquarks. The description of hadronic properties which strongly emphasizes the role of the minimum-quark-content part of the wave function of a hadron is generically called the quark model. It exists

260

quarkmod.dvi  

NLE Websites -- All DOE Office Websites (Extended Search)

August August 2011 by C. Amsler (University of Z¨ urich), T. DeGrand (University of Colorado, Boulder), and B. Krusche (University of Basel). 1.1. Quantum numbers of the quarks Quantum chromodynamics (QCD) is the theory of the strong interactions. QCD is a quantum field theory and its constituents are a set of fermions, the quarks, and gauge bosons, the gluons. Strongly interacting particles, the hadrons, are bound states of quark and gluon fields. As gluons carry no intrinsic quantum numbers beyond color charge, and because color is believed to be permanently confined, most of the quantum numbers of strongly interacting particles are given by the quantum numbers of their constituent quarks and antiquarks. The description of hadronic properties which strongly emphasizes the role of the minimum-quark-content part of the wave function of a hadron is generically called the quark model.

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


261

Quantum Statistical Mechanics and Quantum Computation  

E-Print Network (OSTI)

Quantum Statistical Mechanics and Quantum Computation 22-23 March 2012 Room 111, Jadwin Hall, focused meeting to explore the intersection between quantum statistical mechanics and quantum computation, specifically quantum complexity theory. Advances in complexity theory have interesting implications for physics

262

Inverse Problems in Classical and Quantum Physics  

E-Print Network (OSTI)

The subject of this thesis is in the area of Applied Mathematics known as Inverse Problems. Inverse problems are those where a set of measured data is analysed in order to get as much information as possible on a model which is assumed to represent a system in the real world. We study two inverse problems in the fields of classical and quantum physics: QCD condensates from tau-decay data and the inverse conductivity problem. We use a functional method which allows us to extract within rather general assumptions phenomenological parameters of QCD (the condensates) from a comparison of the time-like experimental data with asymptotic space-like results from theory. The price to be paid for the generality of assumptions is relatively large errors in the values of the extracted parameters. Although we do not claim that our method is superior to other approaches, we hope that our results lend additional confidence to the numerical results obtained with the help of methods based on QCD sum rules. In this thesis, also two approaches of EIT image reconstruction are proposed. The first is based on reformulating the inverse problem in terms of integral equations. This method uses only a single set of measurements for the reconstruction. The second approach is an algorithm based on linearisation which uses more then one set of measurements. A promising result is that one can qualitatively reconstruct the conductivity inside the cross-section of a human chest. Even though the human volunteer is neither two-dimensional nor circular, such reconstructions can be useful in medical applications: monitoring for lung problems such as accumulating fluid or a collapsed lung and noninvasive monitoring of heart function and blood flow.

Andrea A. Almasy

2009-12-02T23:59:59.000Z

263

Quantum discord in open quantum systems  

E-Print Network (OSTI)

Open quantum systems have attracted great attentions for the inevitable interaction between quantum systems and their environment would largely affect the features of interest in the systems. Quantum discord, as a measure of the total nonclassical correlation in a quantum system, includes but not only the distinct property of quantum entanglement. Quantum discord can exist in separated quantum states and it has been shown to play important roles in many fundamental physical problems and practical quantum information tasks. There have been plentiful investigations on the quantum discord and its counterpart classical correlation in open quantum systems. In this short review, we would focus on the recent development and applications of distinctive properties of quantum discord and classical correlation in open quantum systems. Several related experimental works are included.

Xu, Jin-Shi

2012-01-01T23:59:59.000Z

264

Quantum Coulomb Gases  

E-Print Network (OSTI)

Lectures on Quantum Coulomb gases delivered at the CIME summer school on Quantum Many Body Systems 2010

Jan Philip Solovej

2010-12-23T23:59:59.000Z

265

Measurement and QCD analysis of event shape variables in deep-inelastic electron-proton collisions at HERA  

E-Print Network (OSTI)

Measurement and QCD analysis of event shape variables in deep-inelastic electron-proton collisions at HERA

Kluge, T

2004-01-01T23:59:59.000Z

266

Next-to-leading order QCD corrections to light Higgs Pair production via vector boson fusion  

E-Print Network (OSTI)

We present the NLO QCD corrections for light Higgs pair production via vector boson fusion at the LHC within the CP conserving type II two higgs doublet model in the form of a fully flexible parton--level Monte Carlo program. Scale dependences on integrated cross sections and distributions are reduced with QCD K-factors of order unity.

Terrance Figy

2008-06-13T23:59:59.000Z

267

QCD Theory at the XL Rencontre de Moriond: Fish Eyes and Physics  

E-Print Network (OSTI)

I review a selection of the talks at the QCD Session of the XL Rencontre de Moriond, talks either by theorists or else of special theoretical interest. I use the talks to provide some assessment of where we stand with respect to the problems and opportunities facing QCD theory.

Davison E. Soper

2005-06-07T23:59:59.000Z

268

The electrical conductivity and soft photon emissivity of the QCD plasma  

E-Print Network (OSTI)

The electrical conductivity in the hot phase of the QCD plasma is extracted from a quenched lattice measurement of the Euclidean time vector correlator for 1.5 conductivity, and the closely related soft photon emissivity of the QCD plasma, are then extracted from a fit to the Fourier transform of the temporal vector correlator.

Sourendu Gupta

2003-01-09T23:59:59.000Z

269

Nonzero Mean Squared Momentum of Quarks in the Non-Perturbative QCD Vacuum  

E-Print Network (OSTI)

The non-local vacuum condensates of QCD describe the distributions of quarks and gluons in the non-perturbative QCD vacuum. Physically, this means that vacuum quarks and gluons have nonzero mean-squared momentum, called virtuality. In this paper we study the quark virtuality which is given by the ratio of the local quark-gluon mixed vacuum condensate to the quark local vacuum condensate. The two vacuum condensates are obtained by solving Dyson-Schwinger Equations of a fully dressed quark propagator with an effective gluon propagator. Using our calculated condensates, we obtain the virtuality of quarks in the QCD vacuum state. Our numerical predictions differ from the other theoretical model calculations such as QCD sum rules, Lattice QCD and instanton models.

Zhou, Li-Juan; Ma, Wei-xing

2009-01-01T23:59:59.000Z

270

The Electric Dipole Moment of the Nucleons in Holographic QCD  

E-Print Network (OSTI)

We introduce the strong CP-violation in the framework of AdS/QCD model and calculate the electric dipole moments of nucleons as well as the CP-violating pion-nucleon coupling. Our holographic estimate of the electric dipole moments gives for the neutron d_n=1.08 X 10^{-16} theta (e cm), which is comparable with previous estimates. We also predict that the electric dipole moment of the proton should be precisely the minus of the neutron electric dipole moment, thus leading to a new sum rule on the electric dipole moments of baryons.

Hong, Deog Ki; Siwach, Sanjay; Yee, Ho-Ung

2007-01-01T23:59:59.000Z

271

QCD Corrections to Jet Correlations in Weak Boson Fusion  

E-Print Network (OSTI)

Higgs boson production via weak boson fusion is sensitive to the tensor structure of the HVV (V=W,Z) couplings, which distinguishes loop induced vertices from SM expectations. At the CERN Large Hadron Collider this information shows up most clearly in the azimuthal angle correlations of the two forward and backward quark jets which are typical for weak boson fusion. We calculate the next-to-leading order QCD corrections to this process, in the presence of anomalous HVV couplings. Gluon emission does not significantly change the azimuthal jet correlations.

Terrance Figy; Dieter Zeppenfeld

2004-03-30T23:59:59.000Z

272

Elliptic flow from pQCD + saturation + hydro model  

E-Print Network (OSTI)

We have previously predicted multiplicities and transverse momentum spectra of hadrons for the most central LHC Pb+Pb collisions at $\\sqrt{s_{NN}}=5.5$ TeV using initial state for hydrodynamic evolution from pQCD + final state saturation model. By considering binary collision and wounded nucleon profiles we extend these studies to non-central collisions, and predict the $p_{T}$ dependence of minimum bias $v_{2}$ for pions at the LHC. For protons we also show how the $p_{T}$ dependence of $v_2$ changes from RHIC to the LHC.

K. J. Eskola; H. Niemi; P. V. Ruuskanen

2007-05-15T23:59:59.000Z

273

Electrical conductivity and thermal dilepton rate from quenched lattice QCD  

E-Print Network (OSTI)

We report on a continuum extrapolation of the vector current correlation function for light valence quarks in the deconfined phase of quenched QCD. This is achieved by performing a systematic analysis of the influence of cut-off effects on light quark meson correlators at $T\\simeq 1.45 T_c$ using clover improved Wilson fermions. We discuss resulting constraints on the electrical conductivity and the thermal dilepton rate in a quark gluon plasma. In addition new results at 1.2 and 3.0 $T_c$ will be presented.

Olaf Kaczmarek; Anthony Francis

2011-09-19T23:59:59.000Z

274

Electrical conductivity and thermal dilepton rate from quenched lattice QCD  

E-Print Network (OSTI)

We report on a continuum extrapolation of the vector current correlation function for light valence quarks in the deconfined phase of quenched QCD. This is achieved by performing a systematic analysis of the influence of cut-off effects on light quark meson correlators at $T\\simeq 1.45 T_c$ using clover improved Wilson fermions. We discuss resulting constraints on the electrical conductivity and the thermal dilepton rate in a quark gluon plasma. In addition new results at 1.2 and 3.0 $T_c$ will be presented.

Kaczmarek, Olaf

2011-01-01T23:59:59.000Z

275

Two Photon Decays of Charmonia from Lattice QCD  

E-Print Network (OSTI)

We make the first calculation in lattice QCD of two-photon decays of mesons. Working in the charmonium sector, using the LSZ reduction to relate a photon to a sum of hadronic vector eigenstates, we compute form-factors in both the space-like and time-like domains for the transitions $\\eta_c \\to \\gamma^* \\gamma^*$ and $\\chi_{c0} \\to \\gamma^* \\gamma^*$. At the on-shell point we find approximate agreement with experimental world-average values.

Jozef J. Dudek; Robert G. Edwards

2006-07-12T23:59:59.000Z

276

Photoemission with Chemical Potential from QCD Gravity Dual  

E-Print Network (OSTI)

We consider a $D4-D8-\\bar D8$ brane construction which gives rise to a large N QCD at sufficiently small energies. Using the gravity dual of this system, we study chiral phase transition at finite chemical potential and temperature and find a line of first order phase transitions in the phase plane. We compute the spectral function and the photon emission rate. The trace of the spectral function is monotonic at vanishing chemical potential, but develops some interesting features as the value of the chemical potential is increased.

Andrei Parnachev; David A. Sahakyan

2006-10-23T23:59:59.000Z

277

QCD plasma instability and thermalisation at heavy ion collisions  

E-Print Network (OSTI)

Under suitable non-equilibrium conditions QCD plasma can develop plasma instabilities, where some modes of the plasma grow exponentially. It has been argued that these instabilities can play a significant role in the thermalisation of the plasma in heavy-ion collision experiments. We study the instability in SU(2) plasmas using the hard thermal loop effective lattice theory, which is suitable for studying real-time evolution of long wavelength modes in the plasma. We observe that under suitable conditions the plasma can indeed develop an instability which can grow to a very large magnitude, necessary for the rapid thermalisation in heavy-ion collisions.

Dietrich Bodeker; Kari Rummukainen

2007-11-13T23:59:59.000Z

278

Transverse Momentum-Dependent Parton Distributions From Lattice QCD  

Science Conference Proceedings (OSTI)

Starting from a definition of transverse momentum-dependent parton distributions for semi-inclusive deep inelastic scattering and the Drell-Yan process, given in terms of matrix elements of a quark bilocal operator containing a staple-shaped Wilson connection, a scheme to determine such observables in lattice QCD is developed and explored. Parametrizing the aforementioned matrix elements in terms of invariant amplitudes permits a simple transformation of the problem to a Lorentz frame suited for the lattice calculation. Results for the Sivers and Boer-Mulders transverse momentum shifts are presented, focusing in particular on their dependence on the staple extent and the Collins-Soper evolution parameter.

Michael Engelhardt, Bernhard Musch, Philipp Haegler, Andreas Schaefer

2012-12-01T23:59:59.000Z

279

The application of automated perturbation theory to lattice QCD  

E-Print Network (OSTI)

://www.hpc.cam.ac.uk), CSC - IT Center for Science Ltd (http: //www.csc.fi/english) and the PDC Center for High Performance Com- puting (http://www.pdc.kth.se/). ii Abstract Predictions of heavy quark parameters are an integral component of precision tests of the Standard... to nonperturbative studies by the HPQCD collaboration. ii Contents 1 Introduction and overview 1 2 Lattice QCD 5 2.1 Gluons on the lattice . . . . . . . . . . . . . . . . . . . . . . . 6 2.2 Light quarks on the lattice . . . . . . . . . . . . . . . . . . . . 8 2.2.1...

Monahan, Christopher John

2011-11-08T23:59:59.000Z

280

NLO QCD CORRECTIONS TO HADRONIC HIGGS PRODUCTION WITH HEAVY QUARKS.  

SciTech Connect

The production of a Higgs boson in association with a pair of t{bar t} or b{bar b} quarks plays a very important role at both the Tevatron and the Large Hadron Collider. The theoretical prediction of the corresponding cross sections has been improved by including the complete next-to-leading order QCD corrections. After a brief description of the most relevant technical aspects of the calculation, we review the results obtained for both the Tevatron and the Large Hadron Collider.

DAWSON,S.; JACKSON,C.; ORR,L.; REINA,L.; WACHEROTH,D.

2003-07-02T23:59:59.000Z

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


281

Elliptic flow from pQCD + saturation + hydro model  

E-Print Network (OSTI)

We have previously predicted multiplicities and transverse momentum spectra of hadrons for the most central LHC Pb+Pb collisions at $\\sqrt{s_{NN}}=5.5$ TeV using initial state for hydrodynamic evolution from pQCD + final state saturation model. By considering binary collision and wounded nucleon profiles we extend these studies to non-central collisions, and predict the $p_{T}$ dependence of minimum bias $v_{2}$ for pions at the LHC. For protons we also show how the $p_{T}$ dependence of $v_2$ changes from RHIC to the LHC.

Eskola, K J; Ruuskanen, P V

2008-01-01T23:59:59.000Z

282

Chiral Corrections to Baryon Masses Calculated within Lattice QCD  

E-Print Network (OSTI)

Consideration of the analytic properties of pion-induced baryon self energies leads to new functional forms for the extrapolation of light baryon masses. These functional forms reproduce the leading non-analytic behavior of chiral perturbation theory, the correct non-analytic behavior at the $N \\pi$ threshold and the appropriate heavy-quark limit. They involve only three unknown parameters, which may be obtained by fitting lattice QCD data. Recent dynamical fermion results from CP-PACS and UKQCD are extrapolated using these new functional forms. We also use these functions to probe the limit of applicability of chiral perturbation theory.

Anthony W. Thomas; Derek B. Leinweber; Kazuo Tsushima; Stewart V. Wright

1999-09-17T23:59:59.000Z

283

Quantum control limited by quantum decoherence  

E-Print Network (OSTI)

We describe quantum controllability under the influences of the quantum decoherence induced by the quantum control itself. It is shown that, when the controller is considered as a quantum system, it will entangle with its controlled system and then cause quantum decoherence in the controlled system. In competition with this induced decoherence, the controllability will be limited by some uncertainty relation in a well-armed quantum control process. In association with the phase uncertainty and the standard quantum limit, a general model is studied to demonstrate the possibility of realizing a decoherence-free quantum control with a finite energy within a finite time. It is also shown that if the operations of quantum control are to be determined by the initial state of the controller, then due to the decoherence which results from the quantum control itself, there exists a low bound for quantum controllability.

Fei Xue; S. X. Yu; C. P. Sun

2005-07-22T23:59:59.000Z

284

Comprehending Quantum Theory from Quantum Fields  

E-Print Network (OSTI)

At the primary level of reality as described by quantum field theory, a fundamental particle like an electron represents a stable, discrete, propagating excited state of its underlying quantum field. QFT also tells us that the lowest vacuum state as well as the excited states of such a field is always very active with spontaneous, unpredictable quantum fluctuations. Also an underlying quantum field is known to be indestructible and immutable possessing the same value in each element of spacetime comprising the universe. These characteristics of the primary quantum fields together with the fact that the quantum fluctuations can be cogently substantiated to be quantum coherent throughout the universe provide a possible ontology of the quantum theory. In this picture, the wave function of a quantum particle represents the reality of the inherent quantum fluctuations at the core of the universe and endows the particle its counter intuitive quantum behavior.

Mani Bhaumik

2013-10-04T23:59:59.000Z

285

Quantum network coding for quantum repeaters  

E-Print Network (OSTI)

This paper considers quantum network coding, which is a recent technique that enables quantum information to be sent on complex networks at higher rates than by using straightforward routing strategies. Kobayashi et al. have recently showed the potential of this technique by demonstrating how any classical network coding protocol gives rise to a quantum network coding protocol. They nevertheless primarily focused on an abstract model, in which quantum resource such as quantum registers can be freely introduced at each node. In this work, we present a protocol for quantum network coding under weaker (and more practical) assumptions: our new protocol works even for quantum networks where adjacent nodes initially share one EPR-pair but cannot add any quantum registers or send any quantum information. A typically example of networks satisfying this assumption is {\\emph{quantum repeater networks}}, which are promising candidates for the implementation of large scale quantum networks. Our results thus show, for the...

Satoh, Takahiko; Imai, Hiroshi

2012-01-01T23:59:59.000Z

286

NIST Quantum Physics Division - 1998  

Science Conference Proceedings (OSTI)

... QUANTUM PHYSICS DIVISION. Fluorescence Trajectory of a Single 30 Angstrom Radius CdSe Quantum Dot. The quantum ...

287

Quantum computing  

E-Print Network (OSTI)

This article gives an elementary introduction to quantum computing. It is a draft for a book chapter of the "Handbook of Nature-Inspired and Innovative Computing", Eds. A. Zomaya, G.J. Milburn, J. Dongarra, D. Bader, R. Brent, M. Eshaghian-Wilner, F. Seredynski (Springer, Berlin Heidelberg New York, 2006).

J. Eisert; M. M. Wolf

2004-01-05T23:59:59.000Z

288

Quantum Geometry and Quantum Gravity  

E-Print Network (OSTI)

The purpose of this contribution is to give an introduction to quantum geometry and loop quantum gravity for a wide audience of both physicists and mathematicians. From a physical point of view the emphasis will be on conceptual issues concerning the relationship of the formalism with other more traditional approaches inspired in the treatment of the fundamental interactions in the standard model. Mathematically I will pay special attention to functional analytic issues, the construction of the relevant Hilbert spaces and the definition and properties of geometric operators: areas and volumes.

J. Fernando Barbero G.

2008-04-23T23:59:59.000Z

289

Topological charge membranes and Goldstone boson propagation in QCD  

E-Print Network (OSTI)

Both theoretical arguments and Monte Carlo observations indicate that the topological structure of the QCD vacuum consists of a laminated array of extended, coherent codimension-one membranes of alternating sign. Large-$N_c$ arguments, supported by gauge/string holography, indicate that these membranes are domain walls which separate discrete "flux vacua" with values of the topological $\\theta$ parameter which differ by $\\pm 2\\pi$. This exposes a close analogy with 2D U(1) gauge theory, where $\\theta$ can be interpreted as electric polarization, and the domain walls are pointlike charged particles. In 4D QCD, the $\\theta$ parameter represents background Ramond-Ramond flux, which can be interpreted as a polarization of the charged membranes in the vacuum. In this framework, the chiral condensate is formed from the quark surface modes on the membranes. Massless Goldstone boson propagation takes place due to a coordination between bulk oscillations of the polarization field $\\theta$ and the surface currents represented by the Chern-Simons 3-form on the brane surface. This coordination is enforced by overall gauge invariance which imposes an anomaly inflow constraint between bulk and surface currents.

H. B. Thacker

2013-02-03T23:59:59.000Z

290

The chiral magnetic wave in an expanding QCD fluid  

E-Print Network (OSTI)

As a consequence of the chiral anomaly, the hydrodynamics of hot QCD matter coupled to QED allows for a long-wavelength mode of chiral charge density, the chiral magnetic wave (CMW), that provides for a mechanism of electric charge separation along the direction of an external magnetic field. Here, we investigate the efficiency of this mechanism for values of the time-dependent magnetic field and of the energy density attained in the hot QCD matter of ultra-relativistic heavy ion collisions. To this end, we derive the CMW equations of motion for expanding systems by treating the CMW as a charge perturbation on top of an expanding Bjorken-type background field in the limit of small chemical potential. Both, approximate analytical and full numerical solutions to these equations of motion indicate that for the lifetime and thermodynamic conditions of ultra-relativistic heavy ion collisions, the efficiency of CMW-induced electric charge separation decreases with increasing center of mass energy and that the effect is numerically very small. We note, however, that if sizable oriented asymmetries in the axial charge distribution (that are not induced by the CMW) are present in the early fluid dynamic evolution, then the mechanism of CMW-induced electric charge separation can be much more efficient.

Seyed Farid Taghavi; Urs Achim Wiedemann

2013-10-01T23:59:59.000Z

291

Inherently Global Nature of Topological Charge Fluctuations in QCD  

E-Print Network (OSTI)

We have recently presented evidence that in configurations dominating the regularized pure-glue QCD path integral, the topological charge density constructed from overlap Dirac operator organizes into an ordered space-time structure. It was pointed out that, among other properties, this structure exhibits two important features: it is low-dimensional and geometrically global, i.e. consisting of connected sign-coherent regions with local dimensions 1intense topological charge density. To the contrary, the susceptibility saturates only after the space-time regions with most intense fields are included, such that geometrically global structure is already formed. We demonstrate this result both at the fundamental level (full topological density) and at low energy (effective density). The drastic mismatch between the point of fluctuation saturation (~ 50% of space-time at low energy) and that of global structure formation (energy) indicates that the ordered space-time structure in topological charge is inherently global and that topological charge fluctuations in QCD cannot be understood in terms of individual localized pieces. Description in terms of global brane-like objects should be sought instead.

I. Horvath; A. Alexandru; J. B. Zhang; Y. Chen; S. J. Dong; T. Draper; F. X. Lee; K. F. Liu; N. Mathur; S. Tamhankar; H. B. Thacker

2005-01-26T23:59:59.000Z

292

QCD sum rule determination of the charm-quark mass  

Science Conference Proceedings (OSTI)

QCD sum rules involving mixed inverse moment integration kernels are used in order to determine the running charm-quark mass in the MS scheme. Both the high and the low energy expansion of the vector current correlator are involved in this determination. The optimal integration kernel turns out to be of the form p(s)=1-(s{sub 0}/s){sup 2}, where s{sub 0} is the onset of perturbative QCD. This kernel enhances the contribution of the well known narrow resonances, and reduces the impact of the data in the range s{approx_equal}20-25 GeV{sup 2}. This feature leads to a substantial reduction in the sensitivity of the results to changes in s{sub 0}, as well as to a much reduced impact of the experimental uncertainties in the higher resonance region. The value obtained for the charm-quark mass in the MS scheme at a scale of 3 GeV is m{sub c}(3 GeV)=987{+-}9 MeV, where the error includes all sources of uncertainties added in quadrature.

Bodenstein, S. [Centre for Theoretical and Mathematical Physics, University of Cape Town, Rondebosch 7700 (South Africa); Bordes, J.; Penarrocha, J. [Departamento de Fisica Teorica, Universitat de Valencia, and Instituto de Fisica Corpuscular, Centro Mixto Universitat de Valencia-CSIC (Spain); Dominguez, C. A. [Centre for Theoretical and Mathematical Physics, University of Cape Town, Rondebosch 7700 (South Africa); Department of Physics, Stellenbosch University, Stellenbosch 7600 (South Africa); Schilcher, K. [Institut fuer Physik, Johannes Gutenberg-Universitaet Staudingerweg 7, D-55099 Mainz (Germany)

2011-04-01T23:59:59.000Z

293

Quantum and Post Quantum Cryptography Abderrahmane Nitaj  

E-Print Network (OSTI)

Quantum and Post Quantum Cryptography Abderrahmane Nitaj Laboratoire de Math´ematiques Nicolas based on quantum mechanics for factoring large integers and computing discrete loga- rithms undermined Gamal and ECC. However, some cryptosystems, called post quantum cryptosystems, while not currently

Nitaj, Abderrahmane

294

QUANTUM STOCHASTIC CALCULUS AND QUANTUM NONLINEAR FILTERING  

E-Print Network (OSTI)

QUANTUM STOCHASTIC CALCULUS AND QUANTUM NONLINEAR FILTERING V. P. BELAVKIN Abstract. A ?­algebraic inde...nite structure of quantum stochastic (QS) cal- culus is introduced and a continuity property...nitely dimensional nuclear space. The class of nondemolition output QS processes in quantum open systems

Belavkin, Viacheslav P.

295

 

NLE Websites -- All DOE Office Websites (Extended Search)

Döring Döring Bonn University, Bonn, Germany. Resonances: Deciphering the signature of QCD Quantum Chromodynamics (QCD) is the theory of the strong interaction, the fundamental force of nature responsible for the microscopic properties of matter. QCD has left us a signature in form of a rich resonance spectrum, in an energy region where the theory becomes genuinely non-perturbative ---a unique feature that attracts great theoretical interest. QCD manifests itself in these excited states through a complex phenomenology that is currently under intense experimental investigation at JLab and other facilities around the world. From the theory side, non-perturbative approaches have been developed in terms of quarks and gluons, but also relying on hadrons as the relevant degrees of freedom. To connect such

296

Quantum Operations and Measurement  

E-Print Network (OSTI)

Quantum Operations and Measurement M.P Seevinck E-mail: M.P.Seevinck@phys.uu.nl Utrecht field in quantum physics ­ or perhaps better, a new way of doing quantum physics ­ . . . Surprisingly of these developments to the conceptual problems of quantum mechanics. In our view, the new work on quantum information

Seevinck, Michiel

297

Quantum Nanomechanics Pritiraj Mohanty  

E-Print Network (OSTI)

Quantum Nanomechanics Pritiraj Mohanty Abstract Quantum Nanomechanics is the emerging field which pertains to the me- chanical behavior of nanoscale systems in the quantum domain. Unlike the conven- tional studies of vibration of molecules and phonons in solids, quantum nanome- chanics is defined as the quantum

298

Quantum Mechanics Measurements, Mutually  

E-Print Network (OSTI)

Quantum Mechanics Measurements, Mutually Unbiased Bases and Finite Geometry Or why six is the first) #12;Quantum Mechanics for Dummies Finite dimensional quantum states are represented by trace one,1 -icS1,1[ ] #12;Quantum systems evolve and are measured. The evolution of a quantum system using

Gruner, Daniel S.

299

Quantum Operations and Measurement  

E-Print Network (OSTI)

Quantum Operations and Measurement # M.P Seevinck # E­mail: M.P.Seevinck@phys.uu.nl Utrecht in quantum physics -- or perhaps better, a new way of doing quantum physics -- . . . Surprisingly, with few to the conceptual problems of quantum mechanics. In our view, the new work on quantum information changes

Seevinck, Michiel

300

Model Theory and Quantum  

E-Print Network (OSTI)

Model Theory and Quantum Groups Sonia L'Innocente Model Theory and Quantum Groups Sonia L'Innocente (University of Mons) Model Theory and Quantum Groups 1 / 40 #12;Model Theory and Quantum Groups Sonia L quantum plane, submitted. This work is inspired by Ivo Herzog's paper: The pseudo-finite dimensional

Mons-Hainaut, Université de

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301

Lattice QCD and Hydro/Cascade Model of Heavy Ion Collisions  

E-Print Network (OSTI)

We report here on a recent lattice study of the QCD transition region at finite temperature and zero chemical potential using domain wall fermions (DWF). We also present a parameterization of the QCD equation of state obtained from lattice QCD that is suitable for use in hydrodynamics studies of heavy ion collisions. Finally, we show preliminary results from a multi-stage hydrodynamics/hadron cascade model of a heavy ion collision, in an attempt to understand how well the experimental data (e.g. particle spectra, elliptic flow, and HBT radii) can constrain the inputs (e.g. initial temperature, freezeout temperature, shear viscosity, equation of state) of the theoretical model.

Michael Cheng

2010-05-11T23:59:59.000Z

302

Free energy of static quarks and the renormalized Polyakov loop in full QCD  

E-Print Network (OSTI)

We present results from a detailed study of singlet free energies in full QCD with realistic quark masses. An improved scheme for the non-perturbative renormalization of the Polyakov loop is used and we compare its temperature dependence for QCD with different flavor content. We also analyze screening masses extracted from singlet free energies at various temperatures close to and above the QCD transition temperature. We conclude that the temperature dependence of screening masses is well described by perturbation theory up to a non-perturbative pre-factor. An effective running coupling has been determined for all temperature values giving additional insight into screening phenomena at high temperature.

K. Petrov; for the RBC-Bielefeld Collaboration

2007-10-23T23:59:59.000Z

303

Lattice QCD and Hydro/Cascade Model of Heavy Ion Collisions  

E-Print Network (OSTI)

We report here on a recent lattice study of the QCD transition region at finite temperature and zero chemical potential using domain wall fermions (DWF). We also present a parameterization of the QCD equation of state obtained from lattice QCD that is suitable for use in hydrodynamics studies of heavy ion collisions. Finally, we show preliminary results from a multi-stage hydrodynamics/hadron cascade model of a heavy ion collision, in an attempt to understand how well the experimental data (e.g. particle spectra, elliptic flow, and HBT radii) can constrain the inputs (e.g. initial temperature, freezeout temperature, shear viscosity, equation of state) of the theoretical model.

Cheng, Michael

2010-01-01T23:59:59.000Z

304

Quantum Buckling  

E-Print Network (OSTI)

We study the mechanical buckling of a two dimensional membrane coated with a thin layer of superfluid. It is seen that a singularity (vortex or anti-vortex defect) in the phase of the quantum order parameter, distorts the membrane metric into a negative conical singularity surface, irrespective of the defect sign. The defect-curvature coupling and the observed instability is in striking contrast with classical elasticity where, the in-plane strain induced by positive (negative) disclinations is screened by a corresponding positive (negative) conical singularity surface. Defining a dimensionless ratio between superfluid stiffness and membrane bending modulus, we derive conditions under which the quantum buckling instability occurs. An ansatz for the resulting shape of the buckled membrane is analytically and numerically confirmed.

N. Upadhyaya; V. Vitelli

2011-06-23T23:59:59.000Z

305

Quantum Signatures of Spacetime Graininess Quantum Signatures of Spacetime  

E-Print Network (OSTI)

Quantum Signatures of Spacetime Graininess Quantum Signatures of Spacetime "Graininess" Sachindeo September 2009 #12;Quantum Signatures of Spacetime Graininess Introduction 1 Length scales in physics 2 Spacetime noncommutativity from quantum uncertainties 3 Quantum Mechanics on Noncommutative Spacetime 4

306

Quantum Locality?  

Science Conference Proceedings (OSTI)

Robert Griffiths has recently addressed, within the framework of a ‘consistent quantum theory’ (CQT) that he has developed, the issue of whether, as is often claimed, quantum mechanics entails a need for faster-than-light transfers of information over long distances. He argues, on the basis of his examination of certain arguments that claim to demonstrate the existence of such nonlocal influences, that such influences do not exist. However, his examination was restricted mainly to hidden-variable-based arguments that include in their premises some essentially classical-physics-type assumptions that are fundamentally incompatible with the precepts of quantum physics. One cannot logically prove properties of a system by attributing to the system properties alien to that system. Hence Griffiths’ rejection of hidden-variable-based proofs is logically warranted. Griffiths mentions the existence of a certain alternative proof that does not involve hidden variables, and that uses only macroscopically described observable properties. He notes that he had examined in his book proofs of this general kind, and concluded that they provide no evidence for nonlocal influences. But he did not examine the particular proof that he cites. An examination of that particular proof by the method specified by his ‘consistent quantum theory’ shows that the cited proof is valid within that restrictive framework. This necessary existence, within the ‘consistent’ framework, of long range essentially instantaneous influences refutes the claim made by Griffiths that his ‘consistent’ framework is superior to the orthodox quantum theory of von Neumann because it does not entail instantaneous influences. An added section responds to Griffiths’ reply, which cites a litany of ambiguities that seem to restrict, devastatingly, the scope of his CQT formalism, apparently to buttress his claim that my use of that formalism to validate the nonlocality theorem is flawed. But the vagaries that he cites do not upset the proof in question. It is show here in detail why the precise statement of this theorem justifies the specified application of CQT. It is also shown, in response to his challenge, why a putative proof of locality that he has proposed is not valid.

Stapp, Henry

2011-11-10T23:59:59.000Z

307

Electron Ion Collider: The Next QCD Frontier Understanding  

NLE Websites -- All DOE Office Websites (Extended Search)

Electron Electron Ion Collider: The Next QCD Frontier Understanding the glue that binds us all White Paper Writing Committee Elke C. Aschenauer Brookhaven National Laboratory William Brooks Universidad T´ ecnica Federico Santa Maria Abhay Deshpande 1 Stony Brook University Markus Diehl Deutsches Elektronen-Synchrotron DESY Haiyan Gao Duke University Roy Holt Argonne National Laboratory Tanja Horn The Catholic University of America Andrew Hutton Thomas Jefferson National Accelerator Facility Yuri Kovchegov The Ohio State University Krishna Kumar University of Massachusetts, Amherst Zein-Eddine Meziani 1 Temple University Alfred Mueller Columbia University Jianwei Qiu 1 Brookhaven National Laboratory Michael Ramsey-Musolf University of Wisconsin Thomas Roser Brookhaven National Laboratory 1 Co-Editor 1 Franck Sabati´ e Commissariat ` a l' ´ Energie Atomique-Saclay

308

Electric Polarizability of Neutral Hadrons from Lattice QCD  

E-Print Network (OSTI)

By simulating a uniform electric field on a lattice and measuring the change in the rest mass, we calculate the electric polarizability of neutral mesons and baryons using the methods of quenched lattice QCD. Specifically, we measure the electric polarizability coefficient from the quadratic response to the electric field for 10 particles: the vector mesons $\\rho^0$ and $K^{*0}$; the octet baryons n, $\\Sigma^0$, $\\Lambda_{o}^{0}$, $\\Lambda_{s}^{0}$, and $\\Xi^0$; and the decouplet baryons $\\Delta^0$, $\\Sigma^{*0}$, and $\\Xi^{*0}$. Independent calculations using two fermion actions were done for consistency and comparison purposes. One calculation uses Wilson fermions with a lattice spacing of $a=0.10 $fm. The other uses tadpole improved L\\"usher-Weiss gauge fields and clover quark action with a lattice spacing $a=0.17 $fm. Our results for neutron electric polarizability are compared to experiment.

Joe Christensen; Walter Wilcox; Frank X. Lee; Leming Zhou

2004-08-16T23:59:59.000Z

309

Perturbative QCD Description of Heavy and Light Flavor Jet Quenching  

Science Conference Proceedings (OSTI)

We present a successful description of the medium modification of light and heavy flavor jets within a perturbative-QCD-based approach. Only the couplings involving hard partons are assumed to be weak. The effect of the medium on a hard parton, per unit time, is encoded in terms of three nonperturbative, related transport coefficients which describe the transverse momentum squared gained, the elastic energy loss, and diffusion in elastic energy transfer. Scaling the transport coefficients with the temperature of the medium, we achieve a good description of the centrality dependence of the suppression and the azimuthal anisotropy of leading hadrons. Imposing additional constraints based on leading order (LO) hard thermal loop (HTL) effective theory leads to a worsening of the fit, implying the necessity of computing transport coefficients beyond LO HTL.

Qin Guangyou [Department of Physics, Duke University, Durham, North Carolina 27708 (United States); Department of Physics, Ohio State University, Columbus, Ohio 43210 (United States); Majumder, Abhijit [Department of Physics, Ohio State University, Columbus, Ohio 43210 (United States)

2010-12-31T23:59:59.000Z

310

Nuclear matter to strange matter transition in holographic QCD  

E-Print Network (OSTI)

We construct a simple holographic QCD model to study nuclear matter to strange matter transition. The interaction of dense medium and hadrons is taken care of by imposing the force balancing condition for stable D4/D6/D6 configuration. By considering the intermediate and light flavor branes interacting with baryon vertex homogeneously distributed along R^3 space and requesting the energy minimization, we find that there is a well defined transition density as a function of current quark mass. We also find that as density goes up very high, intermediate (or heavy) and light quarks populate equally as expected from the Pauli principle. In this sense, the effect of the Pauli principle is realized as dynamics of D-branes.

Youngman Kim; Yunseok Seo; Sang-Jin Sin

2009-11-19T23:59:59.000Z

311

QCD at imaginary chemical potential with Wilson fermions  

E-Print Network (OSTI)

We investigate the phase diagram in the temperature, imaginary chemical potential plane for QCD with three degenerate quark flavors using Wilson type fermions. While more expensive than the staggered fermions used in past studies in this area, Wilson fermions can be used safely to simulate systems with three quark flavors. In this talk, we focus on the (pseudo)critical line that extends from $\\mu=0$ in the imaginary chemical potential plane, trace it to the Roberge-Weiss line, and determine its location relative to the Roberge-Weiss transition point. In order to smoothly follow the (pseudo)critical line in this plane we perform a multi-histogram reweighting in both temperature and chemical potential. To perform reweighting in the chemical potential we use the compression formula to compute the determinants exactly. Our results are compatible with the standard scenario.

Andrei Alexandru; Anyi Li

2013-12-04T23:59:59.000Z

312

Transverse momentum-dependent parton distribution functions from lattice QCD  

SciTech Connect

Transverse momentum-dependent parton distributions (TMDs) relevant for semi-inclusive deep inelastic scattering (SIDIS) and the Drell-Yan process can be defined in terms of matrix elements of a quark bilocal operator containing a staple-shaped Wilson connection. Starting from such a definition, a scheme to determine TMDs in lattice QCD is developed and explored. Parametrizing the aforementioned matrix elements in terms of invariant amplitudes permits a simple transformation of the problem to a Lorentz frame suited for the lattice calculation. Results for the Sivers and Boer-Mulders transverse momentum shifts are obtained using ensembles at the pion masses 369MeV and 518MeV, focusing in particular on the dependence of these shifts on the staple extent and a Collins-Soper-type evolution parameter quantifying proximity of the staples to the light cone.

Michael Engelhardt, Philipp Haegler, Bernhard Musch, John Negele, Andreas Schaefer

2012-12-01T23:59:59.000Z

313

Transverse momentum-dependent parton distribution functions in lattice QCD  

SciTech Connect

A fundamental structural property of the nucleon is the distribution of quark momenta, both parallel as well as perpendicular to its propagation. Experimentally, this information is accessible via selected processes such as semi-inclusive deep inelastic scattering (SIDIS) and the Drell-Yan process (DY), which can be parametrized in terms of transversemomentum-dependent parton distributions (TMDs). On the other hand, these distribution functions can be extracted from nucleon matrix elements of a certain class of bilocal quark operators in which the quarks are connected by a staple-shaped Wilson line serving to incorporate initial state (DY) or final state (SIDIS) interactions. A scheme for evaluating such matrix elements within lattice QCD is developed. This requires casting the calculation in a particular Lorentz frame, which is facilitated by a parametrization of the matrix elements in terms of invariant amplitudes. Exploratory results are presented for the time-reversal odd Sivers and Boer-Mulders transverse momentum shifts.

Engelhardt, Michael G. [New Mexico State University; Musch, Bernhard U. [Tech. University Munich; Haegler, Philipp G. [Tech. University Munich; Negele, John W. [MIT; Schaefer, Andreas [Regensburg

2013-08-01T23:59:59.000Z

314

A Bayesian analysis of the nucleon QCD sum rules  

E-Print Network (OSTI)

QCD sum rules of the nucleon channel are reanalyzed, using the maximum entropy method (MEM). This new approach, based on the Bayesian probability theory, does not restrict the spectral function to the usual "pole + continuum"-form, allowing a more flexible investigation of the nucleon spectral function. Making use of this flexibility, we are able to investigate the spectral functions of various interpolating fields, finding that the nucleon ground state mainly couples to an operator containing a scalar diquark. Moreover, we formulate the Gaussian sum rule for the nucleon channel and find that it is more suitable for the MEM analysis to extract the nucleon pole in the region of its experimental value, while the Borel sum rule does not contain enough information to clearly separate the nucleon pole from the continuum.

Keisuke Ohtani; Philipp Gubler; Makoto Oka

2011-04-29T23:59:59.000Z

315

Edge States: Topological Insulators, Superconductors and QCD Chiral Bags  

E-Print Network (OSTI)

The dynamics of the magnetic field in a superconducting phase is described by an effective massive bosonic field theory. If the superconductor is confined in a domain M with boundary \\partial M, the boundary conditions of the electromagnetic fields are predetermined by physics. They are time-reversal and also parity invariant for adapted geometry. They lead to edge excitations while in comparison, the bulk energies have a large gap. A similar phenomenon occurs for topological insulators where appropriate boundary conditions for the Dirac Hamiltonian also lead to similar edge states and an 'incompressible bulk'. They give spin-momentum locking as well. In addition time-reversal and parity invariance emerge for adapted geometry. Similar edge states appear in QCD bag models with chiral boundary conditions.

M. Asorey; A. P. Balachandran; J. M. Perez-Pardo

2013-08-26T23:59:59.000Z

316

Automatic O$(a)$ improvement for twisted-mass QCD  

E-Print Network (OSTI)

We present a condition for automatic O$(a)$ improvement in twisted mass lattice QCD, using symmetries of the Symanzik effective theory. If the continuum part of the Symanzik effective theory is invariant under a particular transformation, named $T_1$ in this report, scaling violations of all quantities invariant under $T_1$ transformation are even in the lattice spacing $a$. On the other hand, quantities non-invariant under $T_1$ vanish in the continuum limit with odd powers in $a$. We prove this statement even for the massive case without using the equation of motion. We also consider a few different criteria for the $T_1$ invariant condition in lattice theories and discuss ambiguities of the lattice condition for O$(a)$ improvement.

Sinya Aoki; Oliver Bär

2006-10-18T23:59:59.000Z

317

Chiral Behaviour of the Rho Meson in Lattice QCD  

E-Print Network (OSTI)

In order to guide the extrapolation of the mass of the rho meson calculated in lattice QCD with dynamical fermions, we study the contributions to its self-energy which vary most rapidly as the quark mass approaches zero; from the processes $\\rho \\to \\omega \\pi$ and $\\rho \\to \\pi \\pi$. It turns out that in analysing the most recent data from CP-PACS it is crucial to estimate the self-energy from $\\rho \\to \\pi \\pi$ using the same grid of discrete momenta as included implicitly in the lattice simulation. The correction associated with the continuum, infinite volume limit can then be found by calculating the corresponding integrals exactly. Our error analysis suggests that a factor of 10 improvement in statistics at the lowest quark mass for which data currently exists would allow one to determine the physical rho mass to within 5%. Finally, our analysis throws new light on a long-standing problem with the J-parameter.

D. B. Leinweber; A. W. Thomas; K. Tsushima; S. V. Wright

2001-04-24T23:59:59.000Z

318

Quantum limit in continuous quantum measurement  

E-Print Network (OSTI)

The quantum noise is calculated based on the description of imprecise measurement theory, which is used to analyse the general detector's quantum limit in continuous quantum measurement. Different from the traditional description of the linear-response theory, we don't introduce the hypotheses on the properties of the susceptibilities of the detector, and first show a rigorous result: The minimum noise added by the detector in quantum measurement is precisely equal to the zero-point noise. We also discuss the statistic characters of the back-action force in quantum measurement and show how to reach the quantum limit.

Shao, ChengGang

2012-01-01T23:59:59.000Z

319

Probabilistic bisimulations for quantum processes  

Science Conference Proceedings (OSTI)

Modeling and reasoning about concurrent quantum systems is very important for both distributed quantum computing and quantum protocol verification. As a consequence, a general framework formally describing communication and concurrency in complex quantum ... Keywords: Congruence, Probabilistic bisimulation, Quantum process

Yuan Feng; Runyao Duan; Zhengfeng Ji; Mingsheng Ying

2007-11-01T23:59:59.000Z

320

Quantum Espresso Quick Start Introduction  

E-Print Network (OSTI)

Quantum Espresso Quick Start Introduction Quantum Espresso (http://www.quantum properties eg., phonon dispersion, NMR shifts and band structure to name a few. Quantum Espresso is available. Matter 21, 395502 (2009). Online Guide for QE : http://www.quantum

Bjørnstad, Ottar Nordal

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


321

Magnetic and electric contributions to the energy loss in a dynamical QCD medium  

E-Print Network (OSTI)

The computation of radiative energy loss in a finite size QCD medium with dynamical constituents is a key ingredient for obtaining reliable predictions for jet quenching in ultra-relativistic heavy ion collisions. It was previously shown that energy loss in dynamical QCD medium is significantly higher compared to static QCD medium. To understand this difference, we here analyze magnetic and electric contributions to energy loss in dynamical QCD medium. We find that the significantly higher energy loss in the dynamical case is entirely due to appearance of magnetic contribution in the dynamical medium. While for asymptotically high energies, the energy loss in static and dynamical medium approach the same value, we find that the physical origin of the energy loss in these two cases is different.

Magdalena Djordjevic

2011-05-21T23:59:59.000Z

322

Determination of the ?(1232) axial and pseudoscalar form factors from lattice QCD  

E-Print Network (OSTI)

We present a lattice QCD calculation of the ?(1232) matrix elements of the axial-vector and pseudoscalar currents. The decomposition of these matrix elements into the appropriate Lorentz invariant form factors is carried ...

Alexandrou, Constantia

323

Perturbative renormalization of proton observables in lattice QCD using domain wall fermions  

E-Print Network (OSTI)

Deep inelastic scattering unambiguously measures hadron observables characterizing the quark-gluon structure of hadrons. The only way to calculate these observables from first principles is lattice QCD. Experiments measure ...

Bistrović , Bojan

2005-01-01T23:59:59.000Z

324

N and N to Delta transition form factors from Lattice QCD  

E-Print Network (OSTI)

We present recent lattice QCD results on nucleon form factors and N to Delta transition form factors. We predict the parity violating asymmetry in N to Delta and check the off-diagonal Goldberger-Treiman relation.

C. Alexandrou

2006-11-06T23:59:59.000Z

325

Explorations of the quark substructure of the nucleon in lattice QCD  

E-Print Network (OSTI)

Lattice gauge theory is a valuable tool for understanding how properties of the nucleon arise from the fundamental interactions of QCD. Numerical computations on the lattice can be used not only for first principles ...

Bratt, Jonathan D. (Jonathan Daniel)

2009-01-01T23:59:59.000Z

326

Nuclear Physics from QCD: The Anticipated Impact of Exa?Scale Computing  

Science Conference Proceedings (OSTI)

I discuss highlights in the progress that is being made toward calculating processes of importance in nuclear physics from QCD using high performance computing. As exa?scale computing resources are expected to become available around 2017

Martin J. Savage

2011-01-01T23:59:59.000Z

327

BNL-71205-2003-CP THE TOP QUARK, QCD, AND NEW PHYSICS S  

NLE Websites -- All DOE Office Websites (Extended Search)

top quark mass are discussed in detail. The associated production of a tE pair and a Higgs boson in either e+e- or hadronic collisions is presented at next-to-leading-order QCD and...

328

Forward physics with tagged protons at the LHC: QCD and anomalous couplings  

E-Print Network (OSTI)

We present some physics topics that can be studied at the LHC using proton tagging. We distinguish the QCD (Pomeron structure, BFKL analysis...) from the exploratory physics topics (HIggs boson, anomalous couplings between photons and $W/Z$ bosons

Royon, C

2013-01-01T23:59:59.000Z

329

The QCD Phase Diagram: Large Nc, Quarkyonic Matter and the Triple Point  

SciTech Connect

I discuss the phase diagram of QCD in the large N_c limit. Quarkyonic Matter is described. The properties of QCD matter as measured in the abundance of produced particles are shown to be consistent with this phase diagram. A possible triple point of Hadronic Mater, Deconfined Matter and Quarkyonic matter is shown to explain various behaviors of ratios of particles abundances seen in CERN fixed target experiments.

McLerran L.

2010-01-31T23:59:59.000Z

330

Quark-mass dependence of three-flavor QCD at zero and imaginary chemical potential  

E-Print Network (OSTI)

We draw the three-flavor phase diagram as a function of light and strange quark masses for both zero and imaginary quark-number chemical potential, using the Polyakov-loop extended Nambu--Jona-Lasinio model with an effective four-quark vertex depending on the Polyakov loop. The model prediction is consistent with 2+1 flavor lattice QCD prediction at zero chemical potential and with degenerate three-flavor lattice QCD prediction at imaginary chemical potential.

Sasaki, Takahiro; Kouno, Hiroaki; Yahiro, Masanobu

2011-01-01T23:59:59.000Z

331

From Quantum Cheating to Quantum Security  

E-Print Network (OSTI)

For thousands of years, code-makers and code-breakers have been competing for supremacy. Their arsenals may soon include a powerful new weapon: quantum mechanics. We give an overview of quantum cryptology as of November 2000.

Daniel Gottesman; Hoi-Kwong Lo

2001-11-19T23:59:59.000Z

332

Quantum thermal waves in quantum corrals  

E-Print Network (OSTI)

In this paper the possibility of the generation of the thermal waves in 2D electron gas is investigated. In the frame of the quantum heat transport theory the 2D quantum hyperbolic heat transfer equation is formulated and numerically solved. The obtained solutions are the thermal waves in electron 2D gases. As an exapmle the thermal waves in quantum corrals are described. Key words: 2D electron gas, quantum corrals, thermal waves.

J. Marciak-Kozlowska; M. Kozlowski

2004-05-07T23:59:59.000Z

333

Nuclear Science at NERSC  

NLE Websites -- All DOE Office Websites (Extended Search)

Accelerator Science Accelerator Science Astrophysics Biological Sciences Chemistry & Materials Science Climate & Earth Science Energy Science Engineering Science Environmental Science Fusion Science Math & Computer Science Nuclear Science Science Highlights NERSC Citations HPC Requirements Reviews Home » Science at NERSC » Nuclear Science Nuclear Science Experimental and theoretical nuclear research carried out at NERSC is driven by the quest for improving our understanding of the building blocks of matter. This includes discovering the origins of nuclei and identifying the forces that transform matter. Specific topics include: Nuclear astrophysics and the synthesis of nuclei in stars and elsewhere in the cosmos; Nuclear forces and quantum chromodynamics (QCD), the quantum field

334

Quantum Dimensions and Quantum Galois Theory  

E-Print Network (OSTI)

The quantum dimensions of modules for vertex operator algebras are defined and their properties are discussed. The possible values of the quantum dimensions are obtained for rational vertex operator algebras. A criterion for simple currents of a rational vertex operator algebra is given. A full Galois theory for rational vertex operator algebras is established using the quantum dimensions.

Dong, Chongying; Xu, Feng

2012-01-01T23:59:59.000Z

335

Energy Department Requests Proposals for Advanced Scientific...  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

biology, fusion science, groundwater modeling, high energy physics, nuclear physics, quantum chromodynamics, materials sciences, radiation transport and turbulence. Research...

336

Quantum information in a nutshell () Quantum mechanics + information science  

E-Print Network (OSTI)

Quantum information in a nutshell (�²¤¶) Quantum mechanics + information science = quantum information science = quantum information transfer + quantum algorithm (software) + quantum computer (hardware) + quantum simulation +... = a field rapidly growing in the last 10 years ®v½d¤j¾�ª«²z¨t ±i©ú-õ #12;Brief

Chang, Ming-Che

337

Pion distribution amplitude from holographic QCD and the electromagnetic form factor F{sub {pi}}(Q{sup 2})  

Science Conference Proceedings (OSTI)

The holographic QCD prediction for the pion distribution amplitude (DA) {phi}{sub hol}(u) is used to compute the pion spacelike electromagnetic form factor F{sub {pi}}(Q{sup 2}) within the QCD light-cone sum rule method. In calculations the pion's renormalon-based model twist-4 DA, as well as the asymptotic twist-4 DA are employed. Obtained theoretical predictions are compared with experimental data and with results of the holographic QCD.

Agaev, S. S.; Nobary, M. A. Gomshi [Institute for Physical Problems, Baku State University, Z. Khalilov Street 23, Az-1148 Baku (Azerbaijan); Department of Physics, Faculty of Science, Razi University, Kermanshah (Iran, Islamic Republic of)

2008-04-01T23:59:59.000Z

338

THERMODYNAMICS OF TWO-FLAVOR LATTICE QCD WITH AN IMPROVED WILSON QUARK ACTION AT NON-ZERO TEMPERATURE AND DENSITY.  

SciTech Connect

The authors report the current status of the systematic studies of the QCD thermodynamics by lattice QCD simulations with two flavors of improved Wilson quarks. They evaluate the critical temperature of two flavor QCD in the chiral limit at zero chemical potential and show the preliminary result. Also they discuss fluctuations at none-zero temperature and density by calculating the quark number and isospin susceptibilities and their derivatives with respect to chemical potential.

MAEZAWA,Y.; AOKI, S.; EJIRI, S.; HATSUDA, T.; ISHII, N.; KANAYA, K.; UKITA, N.

2006-11-14T23:59:59.000Z

339

Applied Quantum Information Science  

Science Conference Proceedings (OSTI)

Applied Quantum Information Science. Summary: Theory is being developed and used to devise methods for preserving ...

2012-05-30T23:59:59.000Z

340

Quantum Dating Market  

E-Print Network (OSTI)

We consider the dating market decision problem under the quantum mechanics point of view. Quantum states whose associated amplitudes are modified by men strategies are used to represent women. Grover quantum search algorithm is used as a playing strategy. Success is more frequently obtained by playing quantum than playing classic.

O. G. Zabaleta; C. M. Arizmendi

2010-03-04T23:59:59.000Z

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


341

Quantum Dots Executive Overview  

E-Print Network (OSTI)

Quantum Dot Sol-Gel Nanocomposites (patent pending) n Nanocrystal Quantum Dot Light Emitting Diode (patent (CRADA) Business Opportunities LANL's quantum dot portfolio includes a high-efficiency light emitting diode (LED) design based on non-radiative energy transfer from a quantum well into a layer of colloidal

342

Ergodic Quantum Computing  

Science Conference Proceedings (OSTI)

We propose a (theoretical) model for quantum computation where the result can be read out from the time average of the Hamiltonian dynamics of a 2-dimensional crystal on a cylinder.The Hamiltonian is a spatially local interaction among Wigner--Seitz ... Keywords: Hamiltonian of a quantum computer, Quantum cellular automata, solid state quantum computing, thermodynamics of computation

Dominik Janzing; Pawel Wocjan

2005-06-01T23:59:59.000Z

343

Quantum chaology Michael Berry  

E-Print Network (OSTI)

1 Quantum chaology Michael Berry Physics Department, University of Bristol Physics pp104-5 of Quantum: a guide for the perplexed by Jim Al-Khalili (Weidenfeld and Nicolson 2003) The quantum world appears very different from the world of classical physics that it superseded. Quantum energy levels

Berry, Michael Victor

344

QUANTUM GROUPS JOHAN KUSTERMANS  

E-Print Network (OSTI)

QUANTUM GROUPS JOHAN KUSTERMANS Syllabus: #15; The de#12;nition of a locally compact quantum group: motivational ex- amples and special cases. The classical case, compact and discrete quantum groups. #15 for weights. #15; The general de#12;nition of a locally compact quantum group and its basic consequences

Schürmann, Michael

345

Quantum Statistics Madalin Guta  

E-Print Network (OSTI)

Quantum Statistics Madalin Gut¸a School of Mathematics University of Nottingham 1 #12;The old paradigm Quantum Mechanics up to the 80's Quantum measurements have random results Only probability particles, any more than we can raise Ichtyosauria in the zoo 2 #12;The new paradigm Individual quantum

Guta, Madalin

346

Quantum Walks Norio Konno  

E-Print Network (OSTI)

Quantum Walks Norio Konno Yokohama National University Two types of quantum (random) walks, discrete-time (coined) or continuous- time, were introduced as the quantum mechanical extension of the corresponding classical random walks in connection with quantum computing and have been extensively studied over

Schürmann, Michael

347

Quantum Algorithms for Quantum Field Theories  

E-Print Network (OSTI)

Quantum field theory reconciles quantum mechanics and special relativity, and plays a central role in many areas of physics. We develop a quantum algorithm to compute relativistic scattering probabilities in a massive quantum field theory with quartic self-interactions (phi-fourth theory) in spacetime of four and fewer dimensions. Its run time is polynomial in the number of particles, their energy, and the desired precision, and applies at both weak and strong coupling. In the strong-coupling and high-precision regimes, our quantum algorithm achieves exponential speedup over the fastest known classical algorithm.

Stephen P. Jordan; Keith S. M. Lee; John Preskill

2011-11-15T23:59:59.000Z

348

Quantum Algorithms for Quantum Field Theories  

E-Print Network (OSTI)

Quantum field theory reconciles quantum mechanics and special relativity, and plays a central role in many areas of physics. We develop a quantum algorithm to compute relativistic scattering probabilities in a massive quantum field theory with quartic self-interactions (phi-fourth theory) in spacetime of four and fewer dimensions. Its run time is polynomial in the number of particles, their energy, and the desired precision, and applies at both weak and strong coupling. In the strong-coupling and high-precision regimes, our quantum algorithm achieves exponential speedup over the fastest known classical algorithm.

Jordan, Stephen P; Preskill, John

2011-01-01T23:59:59.000Z

349

Quantum discord and Markovianity of quantum dynamics  

E-Print Network (OSTI)

The problem of recognizing (non-)Markovianity of a quantum dynamics is revisited through analyzing quan- tum correlations. We argue that instantaneously-vanishing quantum discord provides a necessary and sufficient condition for Markovianity of a quantum map. This is used to introduce a measure of non-Markovianity. This measure, however, requires demanding knowledge about the system and the environment. By using a quantum correlation monogamy property and an ancillary system, we propose a simplified measure with less require- ments. Non-Markovianity is thereby decided by quantum state tomography of the system and the ancilla.

Alipour, S

2012-01-01T23:59:59.000Z

350

LANL | Physics | Quantum Information  

NLE Websites -- All DOE Office Websites (Extended Search)

Breakthrough quantum information Breakthrough quantum information science and technology Physics Division's quantum information science and technology capability supports present and future Laboratory missions in cyber-security, sensing, nonproliferation, information science, and materials. Collaborating with researchers throughout Los Alamos and leading institutions in the nation, Physics Division scientists are involved in projects in quantum communications, including quantum key distribution and quantum-enabled security and networking, and in quantum cold-atom physics. Recent fundamental science results include the ability to "paint" potentials that can trap Bose-Einstein condensates into geometric forms, such as the toroidal ring of clusters, the density of which is measured in

351

Quantum extended crystal PDE's  

E-Print Network (OSTI)

Our recent results on {\\em extended crystal PDE's} are generalized to PDE's in the category $\\mathfrak{Q}_S$ of quantum supermanifolds. Then obstructions to the existence of global quantum smooth solutions for such equations are obtained, by using algebraic topologic techniques. Applications are considered in details to the quantum super Yang-Mills equations. Furthermore, our geometric theory of stability of PDE's and their solutions, is also generalized to quantum extended crystal PDE's. In this way we are able to identify quantum equations where their global solutions are stable at finite times. These results, are also extended to quantum singular (super)PDE's, introducing ({\\em quantum extended crystal singular (super) PDE's}).

Agostino Prástaro

2011-05-01T23:59:59.000Z

352

Quantum Computational Complexity John Watrous  

E-Print Network (OSTI)

Quantum Computational Complexity John Watrous Institute for Quantum Computing and School of the subject and its importance II. Introduction III. The quantum circuit model IV. Polynomial-time quantum computations V. Quantum proofs VI. Quantum interactive proof systems VII. Other selected notions in quantum

Watrous, John

353

Quantum optical waveform conversion  

E-Print Network (OSTI)

Currently proposed architectures for long-distance quantum communication rely on networks of quantum processors connected by optical communications channels [1,2]. The key resource for such networks is the entanglement of matter-based quantum systems with quantum optical fields for information transmission. The optical interaction bandwidth of these material systems is a tiny fraction of that available for optical communication, and the temporal shape of the quantum optical output pulse is often poorly suited for long-distance transmission. Here we demonstrate that nonlinear mixing of a quantum light pulse with a spectrally tailored classical field can compress the quantum pulse by more than a factor of 100 and flexibly reshape its temporal waveform, while preserving all quantum properties, including entanglement. Waveform conversion can be used with heralded arrays of quantum light emitters to enable quantum communication at the full data rate of optical telecommunications.

Kielpinski, D; Wiseman, HM

2010-01-01T23:59:59.000Z

354

Quantum Ice : a quantum Monte Carlo study  

E-Print Network (OSTI)

Ice states, in which frustrated interactions lead to a macroscopic ground-state degeneracy, occur in water ice, in problems of frustrated charge order on the pyrochlore lattice, and in the family of rare-earth magnets collectively known as spin ice. Of particular interest at the moment are "quantum spin ice" materials, where large quantum fluctuations may permit tunnelling between a macroscopic number of different classical ground states. Here we use zero-temperature quantum Monte Carlo simulations to show how such tunnelling can lift the degeneracy of a spin or charge ice, stabilising a unique "quantum ice" ground state --- a quantum liquid with excitations described by the Maxwell action of 3+1-dimensional quantum electrodynamics. We further identify a competing ordered "squiggle" state, and show how both squiggle and quantum ice states might be distinguished in neutron scattering experiments on a spin ice material.

Nic Shannon; Olga Sikora; Frank Pollmann; Karlo Penc; Peter Fulde

2011-05-20T23:59:59.000Z

355

Gluonic Higgs Scalar, Abelianization and Monopoles in QCD -- Similarity and Difference between QCD in the MA Gauge and the NAH Theory  

E-Print Network (OSTI)

We study the similarity and the difference between QCD in the maximally abelian (MA) gauge and the nonabelian Higgs (NAH) theory by introducing the ``gluonic Higgs scalar field'' $\\vec \\phi(x)$ corresponding to the ``color-direction'' of the nonabelian gauge connection. The infrared-relevant gluonic mode in QCD can be extracted by the projection along the color-direction $\\vec \\phi(x)$ like the NAH theory. This projection is manifestly gauge-invariant, and is mathematically equivalent to the ordinary MA projection. Since $\\vec \\phi(x)$ obeys the adjoint gauge transformation and is diagonalized in the MA gauge, $\\vec \\phi(x)$ behaves as the Higgs scalar in the NAH theory, and its hedgehog singularity provides the magnetic monopole in the MA gauge like the NAH theory. We observe this direct correspondence between the monopole appearing in the MA gauge and the hedgehog singularity of $\\vec \\phi(x)$ in lattice QCD, when the gluon field is continuous as in the SU($N_c$) Landau gauge. In spite of several similarities, QCD in the MA gauge largely differs from the NAH theory in the two points: one is infrared monopole condensation, and the other is infrared enhancement of the abelian correlation due to monopole condensation.

Hideo Suganuma; Hiroko Ichie

2004-07-07T23:59:59.000Z

356

Physics as Quantum Information Processing: Quantum Fields as Quantum Automata 1  

E-Print Network (OSTI)

Physics as Quantum Information Processing: Quantum Fields as Quantum Automata 1 Giacomo Mauro D Nazionale di Fisica Nucleare, Gruppo IV, Sezione di Pavia Abstract. Can we reduce Quantum Field Theory (QFT) to a quantum computation? Can physics be simulated by a quantum computer? Do we believe that a quantum field

D'Ariano, Giacomo Mauro

357

A test of first order scaling in Nf=2 QCD  

E-Print Network (OSTI)

We complete our analysis of Nf=2 QCD based on the lattice staggered fermion formulation. Using a series of Monte Carlo simulations at fixed (amq*Ls^yh) one is able to test the universality class with given critical exponent yh. This strategy has been used to test the O(4) universality class and it has been presented at the previous Lattice conferences. No agreement was found with simulations in the mass range amq=[0.01335,0.15] using lattices with Ls=16 up to 32 and Lt=4. With the same strategy, we now investigate the possibility of a first order transition using a new set of Monte Carlo data corresponding to yh=3 in the same mass and volume range as the one used for O(4). A substantial agreement is observed both in the specific heat scaling and in the scaling of the chiral condensate, while the chiral susceptibilities still presents visible deviation from scaling in the mass range explored.

G. Cossu; M. D'Elia; A. Di Giacomo; C. Pica

2007-09-30T23:59:59.000Z

358

Sivers and Boer-Mulders observables from lattice QCD.  

SciTech Connect

We present a first calculation of transverse momentum dependent nucleon observables in dynamical lattice QCD employing non-local operators with staple-shaped, 'process-dependent' Wilson lines. The use of staple-shaped Wilson lines allows us to link lattice simulations to TMD effects determined from experiment, and in particular to access non-universal, naively time-reversal odd TMD observables. We present and discuss results for the generalized Sivers and Boer-Mulders transverse momentum shifts for the SIDIS and DY cases. The effect of staple-shaped Wilson lines on T-even observables is studied for the generalized tensor charge and a generalized transverse shift related to the worm gear function g{sub 1}T. We emphasize the dependence of these observables on the staple extent and the Collins-Soper evolution parameter. Our numerical calculations use an n{sub f} = 2+1 mixed action scheme with domain wall valence fermions on an Asqtad sea and pion masses 369 MeV as well as 518 MeV.

B.U. Musch, Ph. Hagler, M. Engelhardt, J.W. Negele, A. Schafer

2012-05-01T23:59:59.000Z

359

The Chern-Simons Diffusion Rate in Improved Holographic QCD  

E-Print Network (OSTI)

In (3+1)-dimensional SU(Nc) Yang-Mills (YM) theory, the Chern-Simons diffusion rate, Gamma_{CS}, is determined by the zero-momentum, zero-frequency limit of the retarded two-point function of the CP-odd operator tr[F ^ F], with F the YM field strength. The Chern-Simons diffusion rate is a crucial ingredient for many CP-odd phenomena, including the chiral magnetic effect in the quark-gluon plasma. We compute Gamma_{CS} in the high-temperature, deconfined phase of Improved Holographic QCD, a refined holographic model for large-Nc YM theory. Our result for Gamma_{CS}/(sT), where s is entropy density and T is temperature, varies slowly at high T and increases monotonically as T approaches the transition temperature from above. We also study the retarded two-point function of tr[F ^ F] with non-zero frequency and momentum. Our results suggest that the CP-odd phenomena that may potentially occur in heavy ion collisions could be controlled by an excitation with energy on the order of the lightest axial glueball mass.

Umut Gursoy; Ioannis Iatrakis; Elias Kiritsis; Francesco Nitti; Andy O'Bannon

2012-12-17T23:59:59.000Z

360

The Chern-Simons Diffusion Rate in Improved Holographic QCD  

E-Print Network (OSTI)

In (3+1)-dimensional SU(Nc) Yang-Mills (YM) theory, the Chern-Simons diffusion rate, Gamma_{CS}, is determined by the zero-momentum, zero-frequency limit of the retarded two-point function of the CP-odd operator tr[F ^ F], with F the YM field strength. The Chern-Simons diffusion rate is a crucial ingredient for many CP-odd phenomena, including the chiral magnetic effect in the quark-gluon plasma. We compute Gamma_{CS} in the high-temperature, deconfined phase of Improved Holographic QCD, a refined holographic model for large-Nc YM theory. Our result for Gamma_{CS}/(sT), where s is entropy density and T is temperature, varies slowly at high T and increases monotonically as T approaches the transition temperature from above. We also study the retarded two-point function of tr[F ^ F] with non-zero frequency and momentum. Our results suggest that the CP-odd phenomena that may potentially occur in heavy ion collisions could be controlled by an excitation with energy on the order of the lightest axial glueball mass...

Gursoy, Umut; Kiritsis, Elias; Nitti, Francesco; O'Bannon, Andy

2013-01-01T23:59:59.000Z

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


361

Multiquark Correlations in Light Mesons and Baryons from holographic QCD  

Science Conference Proceedings (OSTI)

A hadron's multiquark content reflects itself in the quark composition of the interpolator with which it has maximal overlap. The AdS/CFT dictionary translates the anomalous dimension of this interpolator into a mass correction for the corresponding dual mode. Hence such bulk-mass corrections can carry specific information on multiquark correlations. Two prominent examples are studied by implementing this robust and universal holographic mechanism into AdS/QCD gravity duals. In the baryon sector bulk-mass corrections are used to describe systematic good (i.e. maximally attractive) diquark effects. The baryon sizes are predicted to decrease with increasing good-diquark content, and the masses of all 48 observed light-quark baryon states are reproduced with unprecedented accuracy. Our approach further provides the first holographic description of a dominant tetraquark component in the lowest-lying scalar mesons. The tetraquark ground state emerges naturally as the lightest scalar nonet whereas higher excitations become heavier than their quark--antiquark counterparts and are thus likely to dissolve into the multiparticle continuum.

Forkel, Hilmar [Institut fuer Physik, Humboldt-Universitaet zu Berlin, D-12489 Berlin (Germany)

2011-10-21T23:59:59.000Z

362

QCD Thermodynamics with Three Flavors of Improved Staggered Quarks  

E-Print Network (OSTI)

We report on a study of QCD thermodynamics with three flavors of quarks, using a Symanzik improved gauge action and the Asqtad O(a^2) improved staggered quark action. Simulations were carried out with lattice spacings 1/4T, 1/6T and 1/8T both for three degenerate quarks with masses less than or equal to the strange quark mass, m_s, and for degenerate up and down quarks with masses in the range 0.1 m_s \\leq m_{u,d} \\leq 0.6 m_s, and the strange quark mass fixed near its physical value. We present results for standard thermodynamics quantities, such as the Polyakov loop, the chiral order parameter and its susceptibility. For the quark masses studied to date we find a rapid crossover rather than a bona fide phase transition. We have carried out the first calculations of quark number susceptibilities with three flavors of sea quarks. These quantities are of physical interest because they are related to event-by-event fluctuations in heavy ion collision experiments. Comparison of susceptibilities at different lattice spacings show that our results are close to the continuum values.

The MILC Collaboration; C. Bernard; T. Burch; C. DeTar; Steven Gottlieb; E. B. Gregory; U. M. Heller; J. Osborn; R. Sugar; D. Toussaint

2004-05-27T23:59:59.000Z

363

D Pi scattering and D meson resonances from lattice QCD  

E-Print Network (OSTI)

The masses and widths of the broad scalar D_0^*(2400) and the axial D_1(2430) charmed-light resonances are extracted by simulating the corresponding D Pi and D* Pi scattering on the lattice. The resonance parameters are obtained using a Breit-Wigner fit of the elastic phase shifts. The resulting D_0^*(2400) mass is 351+/-21 MeV above the spin-average 1/4(m_D+3m_{D*}), in agreement with the experimental value of 347+/-29 MeV above. The resulting D_0^* to D Pi coupling g^{lat}=2.55+/-0.21 GeV is close to the experimental value g^{exp}simulation of the scattering in these channels incorporates quark-antiquark as well as multi-hadron interpolators, and the distillation method is used for contractions. In addition, the ground and several excited charm-light and charmonium states with various J^P are calculated using standard quark-antiquark interpolators. Our simulations are done in lattice QCD with two-dynamical light quarks at a mass corresponding to m_\\pi\\approx 266 MeV.

Daniel Mohler; Sasa Prelovsek; R. M. Woloshyn

2012-08-20T23:59:59.000Z

364

Geometrical perspective on quantum states and quantum computation  

E-Print Network (OSTI)

We interpret quantum computing as a geometric evolution process by reformulating finite quantum systems via Connes' noncommutative geometry. In this formulation, quantum states are represented as noncommutative connections, while gauge transformations on the connections play a role of unitary quantum operations. Thereby, a geometrical model for quantum computation is presented, which is equivalent to the quantum circuit model. This result shows a geometric way of realizing quantum computing and as such, provides an alternative proposal of building a quantum computer.

Zeqian Chen

2013-11-20T23:59:59.000Z

365

Macroscopic quantum behaviour of periodic quantum systems  

E-Print Network (OSTI)

In this paper we introduce a simple procedure for computing the macroscopic quantum behaviour of periodic quantum systems in the high energy regime. The macroscopic quantum coherence is ascribed to a one-particle state, not to a condensate of a many-particle system; and we are referring to a system of high energy but with few degrees of freedom. We show that, in the first order of approximation, the quantum probability distributions converge to its classical counterparts in a clear fashion, and that the interference effects are strongly suppressed. The harmonic oscillator provides a testing ground for these ideas and yields excellent results.

A. Martín-Ruiz; J. Bernal; Adrián Carbajal-Domínguez

2013-09-02T23:59:59.000Z

366

Modeling Quantum Information Systems abstract  

Science Conference Proceedings (OSTI)

Paul E. Black and Andrew W. Lane, Modeling Quantum Information Systems, Proc. SPIE, Vol. 5436, Quantum Information ...

2013-05-07T23:59:59.000Z

367

Quantum logic and coherent control  

Science Conference Proceedings (OSTI)

... CS Wood, "Quantum Computation, Spectroscopy of ... K. Fujikawa (Elsevier Science, Amsterdam, 1999 ... of trapped atomic ions," Advances in Quantum ...

2013-06-15T23:59:59.000Z

368

NIST Quantum Physics Division Staff  

Science Conference Proceedings (OSTI)

Quantum Physics Division. Staff. Name, Position, Phone. ... Physics Laboratory. Quantum Physics Division. Thomas O'Brian, Acting Chief. ...

2013-09-10T23:59:59.000Z

369

Applications of AdS/QCD and Light-Front Holography to Baryon Physics  

SciTech Connect

The correspondence between theories in anti-de Sitter space and field theories in physical space-time leads to an analytic, semiclassical model for strongly-coupled QCD which has scale invariance at short distances and color confinement at large distances. These equations, for both mesons and baryons, give a very good representation of the observed hadronic spectrum, including a zero mass pion. Light-front holography allows hadronic amplitudes in the AdS fifth dimension to be mapped to frame-independent light-front wavefunctions of hadrons in physical space-time, thus providing a relativistic description of hadrons at the amplitude level. The meson and baryon wavefunctions derived from light-front holography and AdS/QCD also have remarkable phenomenological features, including predictions for the electromagnetic form factors and decay constants. The approach can be systematically improved using light-front Hamiltonian methods. Some novel features of QCD for baryon physics are also discussed.

Brodsky, Stanley J.; /SLAC; de Teramond, Guy F.; /Costa Rica U.

2011-08-22T23:59:59.000Z

370

Light-Front Holography and QCD Hadronization at the Amplitude Level  

E-Print Network (OSTI)

Light-front holography allows hadronic amplitudes in the AdS/QCD fifth dimension to be mapped to frame-independent light-front wavefunctions of hadrons in physical space-time, thus providing a relativistic description of hadrons at the amplitude level. The AdS coordinate z is identified with an invariant light-front coordinate zeta which separates the dynamics of quark and gluon binding from the kinematics of constituent spin and internal orbital angular momentum. The result is a single-variable light-front Schrodinger equation for QCD which determines the eigenspectrum and the light-front wavefunctions of hadrons for general spin and orbital angular momentum. A new method for computing the hadronization of quark and gluon jets at the amplitude level using AdS/QCD light-front wavefunctions is outlined.

Stanley J. Brodsky; Guy de Teramond

2009-01-07T23:59:59.000Z

371

Core collapse supernovae in the QCD phase diagram  

SciTech Connect

We compare two classes of hybrid equations of state with a hadron-to-quark matter phase transition in their application to core collapse supernova simulations. The first one uses the quark bag model and describes the transition to three-flavor quark matter at low critical densities. The second one employs a Polyakov-loop extended Nambu-Jona-Lasinio (PNJL) model with parameters describing a phase transition to two-flavor quark matter at higher critical densities. These models possess a distinctly different temperature dependence of their transition densities which turns out to be crucial for the possible appearance of quark matter in supernova cores. During the early post-bounce accretion phase quark matter is found only if the phase transition takes place at sufficiently low densities as in the study based on the bag model. The increase critical density with increasing temperature, as obtained for our PNJL parametrization, prevents the formation of quark matter. The further evolution of the core collapse supernova as obtained applying the quark bag model leads to a structural reconfiguration of the central protoneutron star where, in addition to a massive pure quark matter core, a strong hydrodynamic shock wave forms and a second neutrino burst is released during the shock propagation across the neutrinospheres. We discuss the severe constraints in the freedom of choice of quark matter models and their parametrization due to the recently observed 2M{sub Circled-Dot-Operator} pulsar and their implications for further studies of core collapse supernovae in the QCD phase diagram.

Fischer, T., E-mail: t.fischer@gsi.de [Helmholtzzentrum fuer Schwerionenforschung GmbH, GSI (Germany); Blaschke, D. [University of Wroclaw, Institute for Theoretical Physics (Poland); Hempel, M. [University of Basel, Department of Physics (Switzerland); Klaehn, T.; Lastowiecki, R. [University of Wroclaw, Institute for Theoretical Physics (Poland); Liebendoerfer, M. [University of Basel, Department of Physics (Switzerland); Martinez-Pinedo, G. [Helmholtzzentrum fuer Schwerionenforschung GmbH, GSI (Germany); Pagliara, G.; Sagert, I. [Ruprecht-Karls-Universitaet, Institut fuer Theoretische Physik (Germany); Sandin, F. [Lulea Tekniska Universitet, Department of Computer Science and Electrical Engineering, EISLAB (Sweden); Schaffner-Bielich, J. [Ruprecht-Karls-Universitaet, Institut fuer Theoretische Physik (Germany); Typel, S. [Helmholtzzentrum fuer Schwerionenforschung GmbH, GSI (Germany)

2012-05-15T23:59:59.000Z

372

QUANTUM CONVERSION IN PHOTOSYNTHESIS  

E-Print Network (OSTI)

W _7405-eng- 4B QUANTUM CONVERSION IN PHOTOSYNTHESIS Melvint r UCRL-9 533 QUANrUM CONVERSION IN PHWOSYNTHESIS * Melvinitself. The primary quantum conversion act is an ionization

Calvin, Melvin

2008-01-01T23:59:59.000Z

373

Instrumentation for quantum computers  

E-Print Network (OSTI)

Quantum computation poses challenging engineering and basic physics issues for the control of nanoscale systems. In particular, experimental realizations of up to seven-qubit NMR quantum computers have acutely illustrated ...

Huang, Wei-Han, 1979-

2004-01-01T23:59:59.000Z

374

Quantum Chevalley groups  

E-Print Network (OSTI)

The goal of this paper is to construct quantum analogues of Chevalley groups inside completions of quantum groups or, more precisely, inside completions of Hall algebras of finitary categories.

Berenstein, Arkady

2012-01-01T23:59:59.000Z

375

Searching with Quantum Computers  

E-Print Network (OSTI)

This article introduces quantum computation by analogy with probabilistic computation. A basic description of the quantum search algorithm is given by representing the algorithm as a C program in a novel way.

Lov K. Grover

2000-11-30T23:59:59.000Z

376

Quantum error control codes  

E-Print Network (OSTI)

It is conjectured that quantum computers are able to solve certain problems more quickly than any deterministic or probabilistic computer. For instance, Shor's algorithm is able to factor large integers in polynomial time on a quantum computer. A quantum computer exploits the rules of quantum mechanics to speed up computations. However, it is a formidable task to build a quantum computer, since the quantum mechanical systems storing the information unavoidably interact with their environment. Therefore, one has to mitigate the resulting noise and decoherence effects to avoid computational errors. In this dissertation, I study various aspects of quantum error control codes - the key component of fault-tolerant quantum information processing. I present the fundamental theory and necessary background of quantum codes and construct many families of quantum block and convolutional codes over finite fields, in addition to families of subsystem codes. This dissertation is organized into three parts: Quantum Block Codes. After introducing the theory of quantum block codes, I establish conditions when BCH codes are self-orthogonal (or dual-containing) with respect to Euclidean and Hermitian inner products. In particular, I derive two families of nonbinary quantum BCH codes using the stabilizer formalism. I study duadic codes and establish the existence of families of degenerate quantum codes, as well as families of quantum codes derived from projective geometries. Subsystem Codes. Subsystem codes form a new class of quantum codes in which the underlying classical codes do not need to be self-orthogonal. I give an introduction to subsystem codes and present several methods for subsystem code constructions. I derive families of subsystem codes from classical BCH and RS codes and establish a family of optimal MDS subsystem codes. I establish propagation rules of subsystem codes and construct tables of upper and lower bounds on subsystem code parameters. Quantum Convolutional Codes. Quantum convolutional codes are particularly well-suited for communication applications. I develop the theory of quantum convolutional codes and give families of quantum convolutional codes based on RS codes. Furthermore, I establish a bound on the code parameters of quantum convolutional codes - the generalized Singleton bound. I develop a general framework for deriving convolutional codes from block codes and use it to derive families of non-catastrophic quantum convolutional codes from BCH codes. The dissertation concludes with a discussion of some open problems.

Abdelhamid Awad Aly Ahmed, Sala

2008-05-01T23:59:59.000Z

377

An electromagnetic signal of the QCD phase transition in neutron star mergers  

E-Print Network (OSTI)

Mergers of binary neutron stars create conditions of supranuclear density $n\\gtrsim n_{\\rm nuc}\\simeq 0.17 {\\rm fm}^{-3}$ and moderate temperature $50\\lesssim T \\lesssim 90 {\\rm MeV}$. These events thus probe a sensitive region of the density-temperature phase diagram of QCD matter. We study photon production by the QCD conformal anomaly for a signal of a possible transition to quark degrees of freedom during the merger. We discuss energy loss due to photon radiation as a cooling mechanism that is sensitive to the bulk viscosity and thermal conductivity of the quark matter.

Pisin Chen; Lance Labun

2013-05-31T23:59:59.000Z

378

Associated Higgs-W-Boson Production at Hadron Colliders: A Fully Exclusive QCD Calculation at NNLO  

SciTech Connect

We consider QCD radiative corrections to standard model Higgs-boson production in association with a W boson in hadron collisions. We present a fully exclusive calculation up to next-to-next-to-leading order (NNLO) in QCD perturbation theory. To perform this NNLO computation, we use a recently proposed version of the subtraction formalism. Our calculation includes finite-width effects, the leptonic decay of the W boson with its spin correlations, and the decay of the Higgs boson into a bb pair. We present selected numerical results at the Tevatron and the LHC.

Ferrera, Giancarlo [Dipartimento di Fisica e Astronomia, Universita di Firenze and INFN, Sezione di Firenze, I-50019 Sesto Fiorentino, Florence (Italy); Grazzini, Massimiliano [Institut fuer Theoretische Physik, Universitaet Zuerich, CH-8057 Zuerich (Switzerland); Tramontano, Francesco [Theory Group, Physics Department, CERN, CH-1211 Geneva 23 (Switzerland)

2011-10-07T23:59:59.000Z

379

Pure annihilation type $ D\\to PP(V)$ decays in the perturbative QCD approach  

E-Print Network (OSTI)

The annihilation type diagrams are difficult to calculate in any kind of models or method. Encouraged by the the successful calculation of pure annihilation type B decays in the perturbative QCD factorization approach, we calculate the pure annihilation type $D\\to PP(V)$ decays in the perturbative QCD approach based on the $k_T$ factorization. Although the expansion parameter $1/m_D$ is not very small, our leading order numerical results agree with the existing experiment data for most channels. We expect the more accurate observation from experiments, which can help us learn about the dynamics of $D$ meson weak decays.

Zhi-Tian Zou; Cheng Li; Cai-Dian Lü

2013-01-15T23:59:59.000Z

380

SPIN Effects, QCD, and Jefferson Laboratory with 12 GeV electrons  

Science Conference Proceedings (OSTI)

QCD and Spin physics are playing important role in our understanding of hadron structure. I will give a short overview of origin of hadron structure in QCD and highlight modern understanding of the subject. Jefferson Laboratory is undergoing an upgrade that will increase the energy of electron beam up to 12 GeV. JLab is one of the leading facilities in nuclear physics studies and once operational in 2015 JLab 12 will be crucial for future of nuclear physics. I will briefly discuss future studies in four experimental halls of Jefferson Lab.

Prokudin, Alexey [JLAB

2013-11-01T23:59:59.000Z

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


381

Finite-temperature spectral function of the vector mesons in a holographic QCD model  

Science Conference Proceedings (OSTI)

We use the soft-wall anti-de Sitter/QCD model to investigate the finite-temperature effects on the spectral function in the vector channel. The dissociation of the vector meson tower onto the anti-de Sitter black hole leads to the in-medium mass shift and the width broadening in a way similar to the lattice QCD results for the heavy quarkonium at finite temperature. We also show the momentum dependence of the spectral function and find it consistent with screening in a hot wind.

Fujita, Mitsutoshi [Department of Physics, Kyoto University, Kyoto 606-8502 (Japan); Fukushima, Kenji; Misumi, Tatsuhiro; Murata, Masaki [Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502 (Japan)

2009-08-01T23:59:59.000Z

382

Finite-temperature spectral function of the vector mesons in an AdS/QCD model  

E-Print Network (OSTI)

We use the soft-wall AdS/QCD model to investigate the finite-temperature effects on the spectral function in the vector channel. The dissociation of the vector meson tower onto the AdS black hole leads to the in-medium mass shift and the width broadening in a way similar to the lattice QCD results for the heavy quarkonium at finite temperature. We also show the momentum dependence of the spectral function and find it consistent with screening in a hot wind.

Mitsutoshi Fujita; Kenji Fukushima; Tatsuhiro Misumi; Masaki Murata

2009-03-13T23:59:59.000Z

383

Scaling laws near the conformal window of many-flavor QCD  

E-Print Network (OSTI)

We derive universal scaling laws for physical observables such as the critical temperature, the chiral condensate, and the pion decay constant as a function of the flavor number near the conformal window of many-flavor QCD in the chiral limit. We argue on general grounds that the associated critical exponents are all interrelated and can be determined from the critical exponent of the running gauge coupling at the Caswell-Banks-Zaks infrared fixed point. We illustrate our findings with the aid of nonperturbative functional Renormalization Group (RG) calculations and low-energy QCD models.

Jens Braun; Holger Gies

2009-12-21T23:59:59.000Z

384

hep-lat/0105004 Are Topological Charge Fluctuations in QCD Instanton  

E-Print Network (OSTI)

We consider a recent proposal by Horváth et al. to address the question whether topological charge fluctuations in QCD are instanton dominated via the response of fermions using lattice fermions with exact chiral symmetry, the overlap fermions. Considering several volumes and lattice spacings we find strong evidence for chirality of a finite density of low-lying eigenvectors of the overlap-Dirac operator in the regions where these modes are peaked. This result suggests instanton dominance of topological charge fluctuations in quenched QCD. Typeset using REVTEX 1 I.

Robert G. Edwards; Urs M. Heller

2008-01-01T23:59:59.000Z

385

Quantum walks: a comprehensive review  

E-Print Network (OSTI)

Quantum walks, the quantum mechanical counterpart of classical random walks, is an advanced tool for building quantum algorithms that has been recently shown to constitute a universal model of quantum computation. Quantum walks is now a solid field of research of quantum computation full of exciting open problems for physicists, computer scientists, mathematicians and engineers. In this paper we review theoretical advances on the foundations of both discrete- and continuous-time quantum walks, together with the role that randomness plays in quantum walks, the connections between the mathematical models of coined discrete quantum walks and continuous quantum walks, the quantumness of quantum walks, a summary of papers published on discrete quantum walks and entanglement as well as a succinct review of experimental proposals and realizations of discrete-time quantum walks. Furthermore, we have reviewed several algorithms based on both discrete- and continuous-time quantum walks as well as a most important resul...

Venegas-Andraca, Salvador E

2012-01-01T23:59:59.000Z

386

Quantum discord as a resource in quantum protocols  

E-Print Network (OSTI)

We show quantum discord to be a resource in quantum information processing. This is accomplished by proving a relation between quantum discord and the yield of the quantum protocols. Our results are derived by studying the fully quantum Slepian-Wolf protocol -- a unification of all bipartite, unidirectional and memoryless quantum communication protocols -- in the presence of noise. As examples, we elucidate the significance of quantum discord in quantum teleportation, superdense coding, and entanglement distillation. Finally, we provide the first quantitative relation between quantum discord and the query complexity of quantum computations.

Madhok, Vaibhav

2012-01-01T23:59:59.000Z

387

Quantum money from knots  

E-Print Network (OSTI)

Quantum money is a cryptographic protocol in which a mint can produce a quantum state, no one else can copy the state, and anyone (with a quantum computer) can verify that the state came from the mint. We present a concrete quantum money scheme based on superpositions of diagrams that encode oriented links with the same Alexander polynomial. We expect our scheme to be secure against computationally bounded adversaries.

Farhi, Edward; Hassidim, Avinatan; Lutomirski, Andrew; Shor, Peter

2010-01-01T23:59:59.000Z

388

Quantum money from knots  

E-Print Network (OSTI)

Quantum money is a cryptographic protocol in which a mint can produce a quantum state, no one else can copy the state, and anyone (with a quantum computer) can verify that the state came from the mint. We present a concrete quantum money scheme based on superpositions of diagrams that encode oriented links with the same Alexander polynomial. We expect our scheme to be secure against computationally bounded adversaries.

Edward Farhi; David Gosset; Avinatan Hassidim; Andrew Lutomirski; Peter Shor

2010-04-28T23:59:59.000Z

389

A Quantum Bousso Bound  

E-Print Network (OSTI)

The Bousso bound requires that one quarter the area of a closed codimension two spacelike surface exceeds the entropy flux across a certain lightsheet terminating on the surface. The bound can be violated by quantum effects such as Hawking radiation. It is proposed that at the quantum level the bound be modified by adding to the area the quantum entanglement entropy across the surface. The validity of this quantum Bousso bound is proven in a two-dimensional large N dilaton gravity theory.

Andrew Strominger; David Thompson

2003-03-10T23:59:59.000Z

390

Testing quantum mechanics  

E-Print Network (OSTI)

As experiments continue to push the quantum-classical boundary to include increasingly complex dynamical systems, the interpretation of experimental data becomes more and more challenging: when the observations are noisy, indirect, and limited, how can we be sure that we are observing quantum behavior? This tutorial highlights some of the difficulties in such experimental tests of quantum mechanics, using optomechanics as the central example, and discusses how the issues can be resolved using techniques from statistics and insights from quantum information theory.

Mankei Tsang

2013-06-12T23:59:59.000Z

391

Quantum Algorithm Zoo  

Science Conference Proceedings (OSTI)

... 27 Andrew M. Childs, Richard Cleve, Stephen P. Jordan, and David Yeung Discrete-query quantum algorithm for NAND trees. ...

2013-11-11T23:59:59.000Z

392

Quantum Physics Portal  

Science Conference Proceedings (OSTI)

... for Science and Technology (CODATA) issues recommended values of the fundamental physical constants ... see all Quantum Physics programs and ...

2013-03-07T23:59:59.000Z

393

Quantum Physics Division Homepage  

Science Conference Proceedings (OSTI)

... Contact. Physical Measurement Laboratory Quantum Physics Division General Information: 303-735-1985 Telephone 303-492-5235 Facsimile. ...

2013-06-28T23:59:59.000Z

394

Quantum Physics Theory  

Science Conference Proceedings (OSTI)

Quantum Physics Theory. Summary: Theoretical work ... constant. The database is available at http://physics.nist.gov/hdel. Precise ...

2010-10-05T23:59:59.000Z

395

Vacuum energy: quantum hydrodynamics vs quantum gravity  

E-Print Network (OSTI)

We compare quantum hydrodynamics and quantum gravity. They share many common features. In particular, both have quadratic divergences, and both lead to the problem of the vacuum energy, which in the quantum gravity transforms to the cosmological constant problem. We show that in quantum liquids the vacuum energy density is not determined by the quantum zero-point energy of the phonon modes. The energy density of the vacuum is much smaller and is determined by the classical macroscopic parameters of the liquid including the radius of the liquid droplet. In the same manner the cosmological constant is not determined by the zero-point energy of quantum fields. It is much smaller and is determined by the classical macroscopic parameters of the Universe dynamics: the Hubble radius, the Newton constant and the energy density of matter. The same may hold for the Higgs mass problem: the quadratically divergent quantum correction to the Higgs potential mass term is also cancelled by the microscopic (trans-Planckian) degrees of freedom due to thermodynamic stability of the whole quantum vacuum.

G. E. Volovik

2005-05-20T23:59:59.000Z

396

Multiphoton Quantum Optics and Quantum State Engineering  

E-Print Network (OSTI)

We present a review of theoretical and experimental aspects of multiphoton quantum optics. Multiphoton processes occur and are important for many aspects of matter-radiation interactions that include the efficient ionization of atoms and molecules, and, more generally, atomic transition mechanisms; system-environment couplings and dissipative quantum dynamics; laser physics, optical parametric processes, and interferometry. A single review cannot account for all aspects of such an enormously vast subject. Here we choose to concentrate our attention on parametric processes in nonlinear media, with special emphasis on the engineering of nonclassical states of photons and atoms. We present a detailed analysis of the methods and techniques for the production of genuinely quantum multiphoton processes in nonlinear media, and the corresponding models of multiphoton effective interactions. We review existing proposals for the classification, engineering, and manipulation of nonclassical states, including Fock states, macroscopic superposition states, and multiphoton generalized coherent states. We introduce and discuss the structure of canonical multiphoton quantum optics and the associated one- and two-mode canonical multiphoton squeezed states. This framework provides a consistent multiphoton generalization of two-photon quantum optics and a consistent Hamiltonian description of multiphoton processes associated to higher-order nonlinearities. Finally, we discuss very recent advances that by combining linear and nonlinear optical devices allow to realize multiphoton entangled states of the electromnagnetic field, that are relevant for applications to efficient quantum computation, quantum teleportation, and related problems in quantum communication and information.

F. Dell'Anno; S. De Siena; F. Illuminati

2007-01-09T23:59:59.000Z

397

Stephen Hawking Quantum Gravity  

E-Print Network (OSTI)

Stephen Hawking and Quantum Gravity Matt Visser Physics Department Washington University Saint Louis USA Science Saturdays 4 Nov 2000 #12; Stephen Hawking and Quantum Gravity Abstract: Through research, Stephen Hawking has captured a place in the popular imagina- tion. Quantum gravity in its various

Visser, Matt

398

Quantum money from knots  

E-Print Network (OSTI)

Quantum money is a cryptographic protocol in which a mint can produce a quantum state, no one else can copy the state, and anyone (with a quantum computer) can verify that the state came from the mint. We present a concrete ...

Farhi, Edward

399

Quantum Computing Computer Scientists  

E-Print Network (OSTI)

Quantum Computing for Computer Scientists Noson S. Yanofsky and Mirco A. Mannucci #12;© May 2007 Noson S. Yanofsky Mirco A. Mannucci #12;Quantum Computing for Computer Scientists Noson S. Yanofsky of Vector Spaces 3 The Leap From Classical to Quantum 3.1 Classical Deterministic Systems 3.2 Classical

Yanofsky, Noson S.

400

Topological Quantum Distillation  

E-Print Network (OSTI)

We construct a class of topological quantum codes to perform quantum entanglement distillation. These codes implement the whole Clifford group of unitary operations in a fully topological manner and without selective addressing of qubits. This allows us to extend their application also to quantum teleportation, dense coding and computation with magic states.

H. Bombin; M. A. Martin-Delgado

2006-05-16T23:59:59.000Z

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


401

The lattice QCD simulation of the quark-gluon mixed condensate g at finite temperature and the phase transition of QCD  

E-Print Network (OSTI)

The thermal effects on the quark-gluon mixed condensate g, which is another chiral order parameter, are studied using the SU(3)c lattice QCD with the Kogut-Susskind fermion at the quenched level. We perform the accurate measurement of the mixed condensate as well as the quark condensate for 0MeVcondensates around T_c \\simeq 280MeV, while the thermal effects below T_c are found to be weak. We also find that the ratio m_0^2 = g/ is almost independent of the temperature even in the very vicinity of T_c, which indicates that the two condensates have nontrivial similarity in the chiral behaviors. We also present the correlation between the condensates and the Polyakov loop to understand the vacuum structure of QCD.

Takumi Doi; Noriyoshi Ishii; Makoto Oka; Hideo Suganuma

2004-09-14T23:59:59.000Z

402

Quantum Gravity: Has Spacetime Quantum Properties?  

E-Print Network (OSTI)

The incompatibility between GR and QM is generally seen as a sufficient motivation for the development of a theory of Quantum Gravity. If - so a typical argumentation - QM gives a universally valid basis for the description of all natural systems, then the gravitational field should have quantum properties. Together with the arguments against semi-classical theories of gravity, this leads to a strategy which takes a quantization of GR as the natural avenue to Quantum Gravity. And a quantization of the gravitational field would in some sense correspond to a quantization of geometry. Spacetime would have quantum properties. But, this strategy will only be successful, if gravity is a fundamental interaction. - What, if gravity is instead an intrinsically classical phenomenon? Then, if QM is nevertheless fundamentally valid, gravity can not be a fundamental interaction. An intrinsically classical gravity in a quantum world would have to be an emergent, induced or residual, macroscopic effect, caused by other interactions. The gravitational field (as well as spacetime) would not have any quantum properties. A quantization of GR would lead to artifacts without any relation to nature. The serious problems of all approaches to Quantum Gravity that start from a direct quantization of GR or try to capture the quantum properties of gravity in form of a 'graviton' dynamics - together with the, meanwhile, rich spectrum of approaches to an emergent gravity and/or spacetime - make this latter option more and more interesting for the development of a theory of Quantum Gravity. The most advanced emergent gravity (and spacetime) scenarios are of an information-theoretical, quantum-computational type.

Reiner Hedrich

2009-02-02T23:59:59.000Z

403

Quantum Information Science | ornl.gov  

NLE Websites -- All DOE Office Websites (Extended Search)

Engineering Analysis Behavioral Sciences Geographic Information Science and Technology Quantum Information Science Quantum Communication and Security Quantum-Enhanced Sensing...

404

Biased nonlocal quantum games  

E-Print Network (OSTI)

We address the question of when quantum entanglement is a useful resource for information processing tasks by presenting a new class of nonlocal games that are simple, direct, generalizations of the Clauser Horne Shimony Holt game. For some ranges of the parameters that specify the games, quantum mechanics offers an advantage, while, surprisingly, for others quantum mechanics is no more powerful than classical mechanics in performing the nonlocal task. This sheds new light on the difference between classical, quantum and super-quantum correlations.

Thomas Lawson; Noah Linden; Sandu Popescu

2010-11-29T23:59:59.000Z

405

Quantum Multiobservable Control  

E-Print Network (OSTI)

We present deterministic algorithms for the simultaneous control of an arbitrary number of quantum observables. Unlike optimal control approaches based on cost function optimization, quantum multiobservable tracking control (MOTC) is capable of tracking predetermined homotopic trajectories to target expectation values in the space of multiobservables. The convergence of these algorithms is facilitated by the favorable critical topology of quantum control landscapes. Fundamental properties of quantum multiobservable control landscapes that underlie the efficiency of MOTC, including the multiobservable controllability Gramian, are introduced. The effects of multiple control objectives on the structure and complexity of optimal fields are examined. With minor modifications, the techniques described herein can be applied to general quantum multiobjective control problems.

Raj Chakrabarti; Rebing Wu; Herschel Rabitz

2008-05-12T23:59:59.000Z

406

Quantum Operation Time Reversal  

E-Print Network (OSTI)

The dynamics of an open quantum system can be described by a quantum operation, a linear, complete positive map of operators. Here, I exhibit a compact expression for the time reversal of a quantum operation, which is closely analogous to the time reversal of a classical Markov transition matrix. Since open quantum dynamics are stochastic, and not, in general, deterministic, the time reversal is not, in general, an inversion of the dynamics. Rather, the system relaxes towards equilibrium in both the forward and reverse time directions. The probability of a quantum trajectory and the conjugate, time reversed trajectory are related by the heat exchanged with the environment.

Crooks, Gavin E

2007-01-01T23:59:59.000Z

407

Quantum Operation Time Reversal  

E-Print Network (OSTI)

The dynamics of an open quantum system can be described by a quantum operation, a linear, complete positive map of operators. Here, I exhibit a compact expression for the time reversal of a quantum operation, which is closely analogous to the time reversal of a classical Markov transition matrix. Since open quantum dynamics are stochastic, and not, in general, deterministic, the time reversal is not, in general, an inversion of the dynamics. Rather, the system relaxes towards equilibrium in both the forward and reverse time directions. The probability of a quantum trajectory and the conjugate, time reversed trajectory are related by the heat exchanged with the environment.

Gavin E. Crooks

2007-06-26T23:59:59.000Z

408

Quantum Physics and Nanotechnology  

E-Print Network (OSTI)

Experimental studies of infinite (unrestricted at least in one direction) quantum particle motion using probe nanotechnologies have revealed the necessity of revising previous concepts of their motion. Particularly, quantum particles transfer quantum motion nonlocality energy beside classical kinetic energy, in other words, they are in two different kinds of motion simultaneously. The quantum component of the motion energy may be quite considerable under certain circumstances. Some new effects were predicted and proved experimentally in terms of this phenomenon. A new prototype refrigerating device was tested, its principle of operation being based on the effect of transferring the quantum component of the motion energy.

Vladimir K. Nevolin

2011-06-06T23:59:59.000Z

409

'Photosynthetic' Quantum Computers?  

E-Print Network (OSTI)

Do quantum computers already exist in Nature? It is proposed that they do. Photosynthesis is one example in which a 'quantum computer' component may play a role in the 'classical' world of complex biological systems. A 'translation' of the standard metabolic description of the 'front-end' light harvesting complex in photosynthesis into the language of quantum computers is presented. Biological systems represent an untapped resource for thinking about the design and operation of hybrid quantum-classical computers and expanding our current conceptions of what defines a 'quantum computer' in Nature.

Scott M. Hitchcock

2001-08-20T23:59:59.000Z

410

Conformal Window and Correlation Functions in Lattice Conformal QCD  

E-Print Network (OSTI)

We discuss various aspects of Conformal Field Theories on the Lattice. We mainly investigate the SU(3) gauge theory with N_f degenerate fermions in the fundamental representation, employing the one-plaquette gauge action and the Wilson fermion action. First we make a brief review of our previous works and thereby clarify the reason why we conjecture that the conformal window is 7 le N_f le 16. Secondly, we introduce a new concept, "conformal theories with an IR cutoff" and point out that any numerical simulation on a lattice is bounded by an IR cutoff Lambda_{IR}. Then we make predictions that when N_f is within the conformal window, the propagator of a meson G(t) behaves at large t, as G(t) = c exp(-m_H t)/t^alpha, that is, a modified Yukawa-type decay form, instead of the usual exponential decay form in the small quark mass region. This holds on an any lattice for any coupling constant g, as far as g is between 0 and g^*, where g^* is the IR fixed point. We verify that numerical results really satisfy the predictions for the N_f=7 case and the N_f=16 case. Thirdly, we discuss small number of flavors (N_f=2 sim 6) QCD at finite temperatures. We point out theoretically and verify numerically that the correlation functions at T/T_c > 1 exhibit the characteristics of the conformal function with IR cutoff, an exponential decay with power correction. Further, we observe our data are consistent with the picture that the N_f=7 case and the N_f=2 at T sim 2 T_c case are close to the meson unparticle model, and we estimate gamma^* = 1.2(1). On the other hand, the N_f=16 case and the N_f=2 at T= 10^2 sim 10^5 Tc cases are close to a free state in the Z(3) twisted vacuum. The results give clues for long standing issues such as slow approach of the free energy to the Stefan-Boltzmann ideal gas limit.

Y. Iwasaki

2012-12-18T23:59:59.000Z

411

Universal quantum computation with shutter logic  

Science Conference Proceedings (OSTI)

We show that universal quantum logic can be achieved using only linear optics and a quantum shutter device. With these elements, we design a quantum memory for any number of qubits and a CNOT gate which are the basis of a universal quantum computer. ... Keywords: interaction-free measurement, optical CNOT gate, optical quantum computation, quantum interrogation, quantum memory, quantum shutter, universal quantum computer

Juan Carlos García-Escartín; Pedro Chamorro-Posada

2006-09-01T23:59:59.000Z

412

Success Stories: Quantum Dots  

NLE Websites -- All DOE Office Websites (Extended Search)

Quantum Dots Outshine the Competition for Biomedical Assays Quantum Dots Outshine the Competition for Biomedical Assays Quantum Dots (Qdots), nano-scale semiconductor crystals that emit a range of bright colors when excited by a light source such as a laser, are shining brightly these days. The Berkeley Lab developed technology has been licensed by Quantum Dot Corporation and is being used as fluorescence probes for biomedical assays. The technology just won an R & D 100 Award and Quantum Dot Corporation was named by Fortune magazine as one of 2004's "Cool Companies." Science honored the technology as one of the Top 10 Breakthroughs of the Year in 2003, and Nanotechnology Now named Quantum Dots as the Best Nanotech Product in 2003, among other honors. Quantum Dot Corporation (QDC) is a 1998 start-up biotechnology company

413

QCD and Electroweak Interference in Higgs production by Gauge Boson Fusion  

E-Print Network (OSTI)

We explicitly calculate the contribution to Higgs production at the LHC from the interference between gluon-gluon and Weak Vector Boson fusion, and compare it to the pure QCD and pure Electro-weak result. While the effect is small at tree level, we speculate it will be significantly enhanced by loop effects.

Jeppe R. Andersen; Jennifer M. Smillie

2006-11-21T23:59:59.000Z

414

QCD Corrections to Vector Boson Pair Production via Weak Boson Fusion  

E-Print Network (OSTI)

NLO-QCD corrections to vector boson pair production via weak boson fusion have recently been calculated and implemented into flexible parton-level Monte-Carlo programs. These allow for the computation of cross sections and kinematical distributions within realistic experimental cuts. We summarize the basic elements of the calculation and review phenomenological results for the LHC.

B. Jager; C. Oleari; D. Zeppenfeld

2006-08-24T23:59:59.000Z

415

Electric charge susceptibility in 2+1 flavour QCD on an anisotropic lattice  

E-Print Network (OSTI)

The FASTSUM Collaboration presents its first results for the electric charge susceptibility in QCD using 2+1 dynamical flavours of Wilson quark on anisotropic lattices. Spatial volumes of (2.94 fm)^3 are used at fixed cut-off with temperatures ranging from below T_c to ~2 T_c.

Pietro Giudice; Gert Aarts; Chris Allton; Alessandro Amato; Simon Hands; Jon-Ivar Skullerud

2013-09-24T23:59:59.000Z

416

Handbook of Higher Twist Distribution Amplitudes of Vector Mesons in QCD  

E-Print Network (OSTI)

We give a summary of existing results on higher twist distribution amplitudes of vector mesons in QCD. Special attention is payed to meson mass corrections which turn out to be large. A ``shopping list'' is presented of most important nonperturbative parameters which enter distribution amplitudes.

Patricia Ball; V. M. Braun

1998-08-05T23:59:59.000Z

417

Associated production of $?(1S)W$ at LHC in next-to-leading order QCD  

E-Print Network (OSTI)

We investigate the complete next-to-leading order (NLO) QCD corrections to $\\Upsilon(1S) +W$ production at the LHC, and predict theoretically the distribution of the $\\Upsilon(1S)$ transverse momentum. We analyse the contributions from different components up to the QCD NLO in the \\ppUW process. Our results show that the \\ppUW process has a large production rate and could be potentially detected at the LHC. We see that the differential cross section for the $\\Upsilon(1S)$ direct-production at the LO is significantly enhanced by the QCD corrections, and the $b\\bar{b} [ ^3S_1^{(8)} ]$ contribution component dominates in the whole plotted $p_T^{\\Upsilon(1S)}$ region. We have also calculated the $\\Upsilon(1S)$ meson indirect-productions via feed-down decays of $\\Upsilon(2S)$, $\\Upsilon(3S)$, $\\chi_{b1}(1P)$, $\\chi_{b2}(1P)$, $\\chi_{b1}(2P)$, and $\\chi_{b2}(2P)$ mesons. We find that the $\\Upsilon(1S)$ indirect-productions can give important contributions to the distribution of $p_T^{\\Upsilon(1S)}$ for the \\ppUW process at the NLO. We conclude that the studying the $\\Upsilon(1S)+W$ production at the LHC could provide an interesting opportunity in testing the nonrelativistic QCD factorization formalism.

Li Gang; Ma Wen-Gan; Song Mao; Zhang Ren-You; Guo Jian-You

2012-12-11T23:59:59.000Z

418

Singularities around the QCD critical point in the complex chemical potential plane  

E-Print Network (OSTI)

We consider thermodynamic singularities appearing in the complex chemical potential plane in the vicinity of QCD critical point. In order to investigate what the singularities are like in a concrete form, we resort to an effective theory based on a mean field approach. We study the behavior of extrema of the real part of the complex effective potential in the complex order parameter plane.

Shinji Ejiri; Yasuhiko Shinno; Hiroshi Yoneyama

2013-11-24T23:59:59.000Z

419

Heavy Quark Production at HERA as a Probe of Hard QCD  

E-Print Network (OSTI)

The study of heavy flavor production is a central topic of research at HERA and is an important testing ground for perturbative QCD. A selection of results for charm and beauty production in gamma p, using different experimental techniques and compared to different theoretical predictions, obtained by the H1 and ZEUS collaborations will be presented.

R. Shehzadi

2009-03-31T23:59:59.000Z

420

Structure function measurements in muon?iron and muon?proton scattering, and a QCD analysis  

Science Conference Proceedings (OSTI)

The structure function F2 has been measured in the range 3.0QCD fits to the scaling violation indicate that the scale?breaking parameter ? is in the region of 100 MeV.

The European Muon Collaboration

1980-01-01T23:59:59.000Z

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


421

The Heavy Quark Free-Energy at TQCD  

E-Print Network (OSTI)

Starting with the modified AdS/QCD metric developed in Ref.[1] we use the Nambu-Goto action to obtain the free energy of a quark-antiquark pair at T

K. Veshgini; E. Megias; J. Nian; H. J. Pirner

2009-11-09T23:59:59.000Z

422

The off shell [rho][endash][omega] mixing in the QCD sum rules  

SciTech Connect

The q[sup 2] dependence of the [rho] - [omega] mixing amplitude is analyzed with the use of the QCD sum rules and the dispersion relation. In going off shell the mixing decreases, changes sign at q[sup 2] [approx equal] 0.4 m[sub [rho

Hatsuda, T. (Washington Univ., Seattle, WA (United States). Dept. of Physics); Henley, E.M. (Washington Univ., Seattle, WA (United States). Dept. of Physics Washington Univ., Seattle, WA (United States). Inst. for Nuclear Theory); Meissner, T. (Washington Univ., Seattle, WA (United States). Inst. for Nuclear Theory); Krein, G. (Instituto de Fisica Teorica (IFT), Sao Paulo, SP (Brazil))

1993-01-01T23:59:59.000Z

423

Large $N_c$ QCD at non-zero chemical potential  

E-Print Network (OSTI)

The general issue of large $N_c$ QCD at nonzero chemical potential is considered with a focus on understanding the difference between large $N_c$ QCD with an isospin chemical potential and large $N_c$ QCD with a baryon chemical potential. A simple diagrammatic analysis analogous to `t Hooft's analysis at $\\mu=0$ implies that the free energy with a given baryon chemical potential is equal to the free energy with an isospin chemical potential of the same value plus $1/N_c$ corrections. Phenomenologically, these two systems behave quite differently. A scenario to explain this difference in light of the diagrammatic analysis is explored. This scenario is based on a phase transition associated with pion condensation when the isospin chemical potential exceeds $m_\\pi/2$; associated with this transition there is breakdown of the $1/N_c$ expansion--in the pion condensed phase there is a distinct $1/N_c$ expansion including a larger set of diagrams. While this scenario is natural, there are a number of theoretical issues which at least superficially challenge it. Most of these can be accommodated. However, the behavior of quenched QCD which raises a number of apparently analogous issues cannot be easily understood completely in terms of an analogous scenario. Thus, the overall issue remains open.

Thomas D. Cohen

2004-10-11T23:59:59.000Z

424

Double Parton Distributions Incorporating Perturbative QCD Evolution and Momentum and Quark Number Sum Rules.  

E-Print Network (OSTI)

of the parton model [1–3] , with subsequent extension to perturbative QCD [4–16] . Such processes have in fact been observed experimentally – both in ?s = 63 GeV pp collisions by the AFS collaboration at the CERN ISR [17] and more recently in ?s = 1.8 TeV pp...

Gaunt, Jonathan R; Stirling, W James

425

Thermodynamics in 2+1 flavor QCD with improved Wilson quarks by the fixed scale approach  

E-Print Network (OSTI)

We study thermodynamic properties of 2+1 flavor QCD with improved Wilson quarks coupled with the RG improved Iwasaki glue, using the fixed scale approach. We present the results for the equation of state, renormalized Polyakov loop, and chiral condensate.

T. Umeda; S. Aoki; S. Ejiri; T. Hatsuda; K. Kanaya; Y. Maezawa; H. Ohno

2012-12-06T23:59:59.000Z

426

CERN-TH/97-371 hep-ph/9712442 QCD AT HIGH ENERGIES ?  

E-Print Network (OSTI)

The following topics in perturbative QCD are reviewed: recent theoretical progress in higher-order calculations; soft-gluon resummation for hard-scattering processes at large ET and high x; low-x behaviour of structure functions and recent theoretical results on BFKL dynamics; infrared renormalons and power corrections to perturbative predictions; updated summary of ?S measurements.

Stefano Catani; Stefano Catani

1997-01-01T23:59:59.000Z

427

Quantum Discord for Investigating Quantum Correlations without Entanglement in Solids  

E-Print Network (OSTI)

Quantum systems unfold diversified correlations which have no classical counterparts. These quantum correlations have various different facets. Quantum entanglement, as the most well known measure of quantum correlations, plays essential roles in quantum information processing. However, it has recently been pointed out that quantum entanglement cannot describe all the nonclassicality in the correlations. Thus the study of quantum correlations in separable states attracts widely attentions. Herein, we experimentally investigate the quantum correlations of separable thermal states in terms of quantum discord. The sudden change of quantum discord is observed, which captures ambiguously the critical point associated with the behavior of Hamiltonian. Our results display the potential applications of quantum correlations in studying the fundamental properties of quantum system, such as quantum criticality of non-zero temperature.

Rong, Xing; Jin, Fangzhou; Geng, Jianpei; Feng, Pengbo; Xu, Nanyang; Wang, Ya; Ju, Chenyong; Shi, Mingjun; Du, Jiangfeng

2012-01-01T23:59:59.000Z

428

Cavity Quantum Electrodynamics (CQED)-Based Quantum LDPC  

E-Print Network (OSTI)

Cavity Quantum Electrodynamics (CQED)-Based Quantum LDPC Encoders and Decoders Volume 3, Number 4-0655/$26.00 ©2011 IEEE #12;Cavity Quantum Electrodynamics (CQED)-Based Quantum LDPC Encoders and Decoders Ivan B: Quantum information processing (QIP) relies on delicate superposition states that are sensitive

Djordjevic, Ivan B.

429

Quantum information and stabilization of quantum states by feedback control  

E-Print Network (OSTI)

Quantum information and stabilization of quantum states by feedback control Hans Maassen September) Karol Zyczkowski (Krakow) #12;Overview #12;Overview 1. Finite quantum systems #12;Overview 1. Finite quantum systems 2. Flow diagrams #12;Overview 1. Finite quantum systems 2. Flow diagrams 3. What

Maassen, Hans

430

(Experimental and theoretical basic research in high energy physics)  

Science Conference Proceedings (OSTI)

This report discusses the measurement of charm and b decays via hadronic production in a hybrid emulsion spectrometer, quantum chromodynamics, quantum electrodynamics, weak interactions, and cosmological applications. (LSP)

Not Available

1991-04-01T23:59:59.000Z

431

Fermilab Today | Boston University Profile  

NLE Websites -- All DOE Office Websites (Extended Search)

simulations of quantum chromodynamics, cosmology, and the application of mathematics to quantum field theory. WHAT SETS PARTICLE PHYSICS AT BOSTON UNIVERSITY APART? We have a...

432

Study of the behavior of nuclear modification factor in freeze-out state  

E-Print Network (OSTI)

One of the latest trends in the advancement of experimental high-energy physics is to identify the quark gluon plasma (QGP) predicted qualitatively by quantum chromodynamics (QCD). We discuss whether nuclear transparency effect which is considered an important phenomenon, connected with dynamics of hadron-nuclear and nuclear-nuclear interactions could reflect some particular properties of the medium. FASTMC is used for Au-Au collision at RHIC energies. Critical change in the transparency is considered a signal on the appearance of new phases of strongly interacting matter and the QGP.

Ajaz, M; Khan, K H; Zaman, A; 10.1088/1674-1137/37/2/024101

2013-01-01T23:59:59.000Z

433

Quantum Fine-Grained Entropy  

E-Print Network (OSTI)

Regarding the strange properties of quantum entropy and entanglement, e.g., the negative quantum conditional entropy, we revisited the foundations of quantum entropy, namely, von Neumann entropy, and raised the new method of quantum fine-grained entropy. With the applications in entanglement theory, quantum information processing, and quantum thermodynamics, we demonstrated the capability of quantum fine-grained entropy to resolve some notable confusions and problems, including the measure of entanglement and quantumness, the additivity conjecture of entanglement of formation etc, and the definition of temperature for single quantum system.

Wang, Dong-Sheng

2012-01-01T23:59:59.000Z

434

Generalized quantum defect methods in quantum chemistry  

E-Print Network (OSTI)

The reaction matrix of multichannel quantum defect theory, K, gives a complete picture of the electronic structure and the electron - nuclear dynamics for a molecule. The reaction matrix can be used to examine both bound ...

Altunata, Serhan

2006-01-01T23:59:59.000Z

435

Quantum transfer operators and quantum scattering  

E-Print Network (OSTI)

These notes describe a new method to investigate the spectral properties if quantum scattering Hamiltonians, developed in collaboration with J. Sj\\"ostrand and M.Zworski. This method consists in constructing a family of "quantized transfer operators" $\\{M(z,h)\\}$ associated with a classical Poincar\\'e section near some fixed classical energy E. These operators are finite dimensional, and have the structure of "open quantum maps". In the semiclassical limit, the family $\\{M(z,h)\\}$ encode the quantum dynamics near the energy E. In particular, the quantum resonances of the form $E+z$, for $z=O(h)$, are obtained as the roots of $\\det(1-M(z,h))=0$.

Stéphane Nonnenmacher

2010-01-22T23:59:59.000Z

436

Quantum Copy-Protection and Quantum Money  

E-Print Network (OSTI)

Forty years ago, Wiesner proposed using quantum states to create money that is physically impossible to counterfeit, something that cannot be done in the classical world. However, Wiesner's scheme required a central bank ...

Aaronson, Scott

437

Multiphoton Quantum Optics and Quantum State Engineering  

E-Print Network (OSTI)

We present a review of theoretical and experimental aspects of multiphoton quantum optics. Multiphoton processes occur and are important for many aspects of matter-radiation interactions that include the efficient ionization of atoms and molecules, and, more generally, atomic transition mechanisms; system-environment couplings and dissipative quantum dynamics; laser physics, optical parametric processes, and interferometry. A single review cannot account for all aspects of such an enormously vast subject. Here we choose to concentrate our attention on parametric processes in nonlinear media, with special emphasis on the engineering of nonclassical states of photons and atoms that are relevant for the conceptual investigations as well as for the practical applications of forefront aspects of modern quantum mechanics. We present a detailed analysis of the methods and techniques for the production of genuinely quantum multiphoton processes in nonlinear media, and the corresponding models of multiphoton effective interactions. We review existing proposals for the classification, engineering, and manipulation of nonclassical

Silvio De Siena; Fabrizio Illuminati

2007-01-01T23:59:59.000Z

438

Quantum Gravity An introductory survey  

E-Print Network (OSTI)

Quantum Gravity An introductory survey Hermann Nicolai Max-Planck-Institut f¨ur Gravitationsphysik (Albert­Einstein­Institut, Potsdam) . ­ p.1/25 #12;Why Quantum Gravity? . ­ p.2/25 #12;Why Quantum Gravity theories: . ­ p.2/25 #12;Why Quantum Gravity? General Relativity and Quantum Theory: not only very

Rossak, Wilhelm R.

439

Quantum Circuit Model Topological Model  

E-Print Network (OSTI)

Quantum Circuit Model Topological Model Comparison of Models Topological Quantum Computation Eric Rowell Texas A&M University October 2010 Eric Rowell Topological Quantum Computation #12;Quantum Circuit Model Topological Model Comparison of Models Outline 1 Quantum Circuit Model Gates, Circuits

Rowell, Eric C.

440

Quantum Copy-Protection and Quantum Money  

E-Print Network (OSTI)

Forty years ago, Wiesner proposed using quantum states to create money that is physically impossible to counterfeit, something that cannot be done in the classical world. However, Wiesner's scheme required a central bank to verify the money, and the question of whether there can be unclonable quantum money that anyone can verify has remained open since. One can also ask a related question, which seems to be new: can quantum states be used as copy-protected programs, which let the user evaluate some function f, but not create more programs for f? This paper tackles both questions using the arsenal of modern computational complexity. Our main result is that there exist quantum oracles relative to which publicly-verifiable quantum money is possible, and any family of functions that cannot be efficiently learned from its input-output behavior can be quantumly copy-protected. This provides the first formal evidence that these tasks are achievable. The technical core of our result is a "Complexity-Theoretic No-Cloning Theorem," which generalizes both the standard No-Cloning Theorem and the optimality of Grover search, and might be of independent interest. Our security argument also requires explicit constructions of quantum t-designs. Moving beyond the oracle world, we also present an explicit candidate scheme for publicly-verifiable quantum money, based on random stabilizer states; as well as two explicit schemes for copy-protecting the family of point functions. We do not know how to base the security of these schemes on any existing cryptographic assumption. (Note that without an oracle, we can only hope for security under some computational assumption.)

Scott Aaronson

2011-10-24T23:59:59.000Z

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


441

Quantum Key Distribution Using Quantum Faraday Rotators  

E-Print Network (OSTI)

We propose a new quantum key distribution (QKD) protocol based on the fully quantum mechanical states of the Faraday rotators. The protocol is unconditionally secure against eavesdropping for single-photon source on a noisy environment and robust against impersonation attacks. It also allows for unconditionally secure key distribution for multiphoton source up to two photons. The protocol could be implemented experimentally with the current spintronics technology on semiconductors.

Choi, T; Choi, Mahn-Soo; Choi, Taeseung

2006-01-01T23:59:59.000Z

442

Quantum Copy-Protection and Quantum Money  

E-Print Network (OSTI)

Forty years ago, Wiesner proposed using quantum states to create money that is physically impossible to counterfeit, something that cannot be done in the classical world. However, Wiesner's scheme required a central bank to verify the money, and the question of whether there can be unclonable quantum money that anyone can verify has remained open since. One can also ask a related question, which seems to be new: can quantum states be used as copy-protected programs, which let the user evaluate some function f, but not create more programs for f? This paper tackles both questions using the arsenal of modern computational complexity. Our main result is that there exist quantum oracles relative to which publicly-verifiable quantum money is possible, and any family of functions that cannot be efficiently learned from its input-output behavior can be quantumly copy-protected. This provides the first formal evidence that these tasks are achievable. The technical core of our result is a "Complexity-Theoretic No-Clon...

Aaronson, Scott

2011-01-01T23:59:59.000Z

443

Quantum physics meets biology  

E-Print Network (OSTI)

Quantum physics and biology have long been regarded as unrelated disciplines, describing nature at the inanimate microlevel on the one hand and living species on the other hand. Over the last decades the life sciences have succeeded in providing ever more and refined explanations of macroscopic phenomena that were based on an improved understanding of molecular structures and mechanisms. Simultaneously, quantum physics, originally rooted in a world view of quantum coherences, entanglement and other non-classical effects, has been heading towards systems of increasing complexity. The present perspective article shall serve as a pedestrian guide to the growing interconnections between the two fields. We recapitulate the generic and sometimes unintuitive characteristics of quantum physics and point to a number of applications in the life sciences. We discuss our criteria for a future quantum biology, its current status, recent experimental progress and also the restrictions that nature imposes on bold extrapolations of quantum theory to macroscopic phenomena.

Markus Arndt; Thomas Juffmann; Vlatko Vedral

2009-11-01T23:59:59.000Z

444

Motion in Quantum Gravity  

E-Print Network (OSTI)

We tackle the question of motion in Quantum Gravity: what does motion mean at the Planck scale? Although we are still far from a complete answer we consider here a toy model in which the problem can be formulated and resolved precisely. The setting of the toy model is three dimensional Euclidean gravity. Before studying the model in detail, we argue that Loop Quantum Gravity may provide a very useful approach when discussing the question of motion in Quantum Gravity.

Karim Noui

2010-03-31T23:59:59.000Z

445

Quantum Effect Materials: Methods of Fabrication of Quantum ... - TMS  

Science Conference Proceedings (OSTI)

Session A: Quantum Effect Materials: Methods of Fabrication of Quantum Dots. Session ... Nanometer size semiconductor crystallites show a striking evolution of  ...

446

Quantum Money with Classical Verification  

E-Print Network (OSTI)

We construct a quantum money scheme that allows verification through classical communication with bank. This is the first demonstration that a secure quantum money scheme exists that does not require quantum communication for coin verification.

Gavinsky, Dmitry

2011-01-01T23:59:59.000Z

447

Quantum gravity on the lattice  

E-Print Network (OSTI)

the Conference Quantum Gravity: Challenges and Perspectives.divergences in quantum gravity. In: Hawking, S.W. , Israel,f ) V n?1 ( f ) = Quantum gravity on the lattice Similarly,

Hamber, Herbert W.

2009-01-01T23:59:59.000Z

448

Quantum Communication Technology  

E-Print Network (OSTI)

Quantum communication is built on a set of disruptive concepts and technologies. It is driven by fascinating physics and by promising applications. It requires a new mix of competencies, from telecom engineering to theoretical physics, from theoretical computer science to mechanical and electronic engineering. First applications have already found their way to niche markets and university labs are working on futuristic quantum networks, but most of the surprises are still ahead of us. Quantum communication, and more generally quantum information science and technologies, are here to stay and will have a profound impact on the XXI century.

Gisin, Nicolas

2010-01-01T23:59:59.000Z

449

Quantum Devices Group Homepage  

Science Conference Proceedings (OSTI)

... Quantum Information and Measurements—America's future prosperity and security may ... For magnetic sensors, spin-based transport in metals and ...

2011-10-03T23:59:59.000Z

450

Quantum-based Measurements  

Science Conference Proceedings (OSTI)

... The physical and biological sciences are converging on the nanoscale and the decades ... A new technology frontier is opening—the quantum world. ...

2010-10-05T23:59:59.000Z

451

Recommended Quantum Communications Links  

Science Conference Proceedings (OSTI)

... qubit.nist.gov. NIST's Physical Measurement Laboratory Quantum Physics Division. www.nist.gov/pml/div689/index.cfm. ...

2013-03-14T23:59:59.000Z

452

Parabolic Quantum Cloak.  

E-Print Network (OSTI)

??It is shown that the parabolic quantum cloak can be theoretically design by using âtransformation design methodâ. We discuss the possibility to build a parabolic… (more)

Chang, Yu-Hsuan

2013-01-01T23:59:59.000Z

453

QUANTUM CONVERSION IN PHOTOSYNTHESIS  

E-Print Network (OSTI)

QUANTUM CONVERSION IN PHOTOSYNTHESIS Melvin Calvin Januaryas it occurs in modern photosynthesis can only take place inof the problem or photosynthesis, or any specific aspect of

Calvin, Melvin

2008-01-01T23:59:59.000Z

454

Quantum Exotic PDE's  

E-Print Network (OSTI)

Following the previous works on the A. Pr\\'astaro's formulation of algebraic topology of quantum (super) PDE's, it is proved that a canonical Heyting algebra ({\\em integral Heyting algebra}) can be associated to any quantum PDE. This is directly related to the structure of its global solutions. This allows us to recognize a new inside in the concept of quantum logic for microworlds. Furthermore, the Prastaro's geometric theory of quantum PDE's is applied to the new category of {\\em quantum hypercomplex manifolds}, related to the well-known Cayley-Dickson construction for algebras. Theorems of existence for local and global solutions are obtained for (singular) PDE's in this new category of noncommutative manifolds. Finally the extension of the concept of exotic PDE's, recently introduced by A.Pr\\'astaro, has been extended to quantum PDE's. Then a smooth quantum version of the quantum (generalized) Poincar\\'e conjecture is given too. These results extend ones for quantum (generalized) Poincar\\'e conjecture, previously given by A. Pr\\'astaro.

Agostino Prástaro

2011-06-04T23:59:59.000Z

455

Quantum Monte Carlo for  

NLE Websites -- All DOE Office Websites (Extended Search)

Quantum Monte Carlo for the Electronic Structure of Atoms and Molecules Brian Austin Lester Group, U.C. Berkeley BES Requirements Workshop Rockville, MD February 9, 2010 Outline...

456

Quantum Confined Structures  

Science Conference Proceedings (OSTI)

Sep 14, 2009 ... Classification of Energy Levels in Quantum Dot Structures by Means of Depleted Layer Spectroscopy Methods: Maria Kaniewska1; Olof ...

457

Quantum convolutional stabilizer codes  

E-Print Network (OSTI)

Quantum error correction codes were introduced as a means to protect quantum information from decoherance and operational errors. Based on their approach to error control, error correcting codes can be divided into two different classes: block codes and convolutional codes. There has been significant development towards finding quantum block codes, since they were first discovered in 1995. In contrast, quantum convolutional codes remained mainly uninvestigated. In this thesis, we develop the stabilizer formalism for quantum convolutional codes. We define distance properties of these codes and give a general method for constructing encoding circuits, given a set of generators of the stabilizer of a quantum convolutional stabilizer code, is shown. The resulting encoding circuit enables online encoding of the qubits, i.e., the encoder does not have to wait for the input transmission to end before starting the encoding process. We develop the quantum analogue of the Viterbi algorithm. The quantum Viterbi algorithm (QVA) is a maximum likehood error estimation algorithm, the complexity of which grows linearly with the number of encoded qubits. A variation of the quantum Viterbi algorithm, the Windowed QVA, is also discussed. Using Windowed QVA, we can estimate the most likely error without waiting for the entire received sequence.

Chinthamani, Neelima

2005-05-01T23:59:59.000Z

458

NMR Quantum Information Processing  

E-Print Network (OSTI)

Nuclear Magnetic Resonance (NMR) has provided a valuable experimental testbed for quantum information processing (QIP). Here, we briefly review the use of nuclear spins as qubits, and discuss the current status of NMR-QIP. Advances in the techniques available for control are described along with the various implementations of quantum algorithms and quantum simulations that have been performed using NMR. The recent application of NMR control techniques to other quantum computing systems are reviewed before concluding with a description of the efforts currently underway to transition to solid state NMR systems that hold promise for scalable architectures.

Chandrasekhar Ramanathan; Nicolas Boulant; Zhiying Chen; David G. Cory; Isaac Chuang; Matthias Steffen

2004-08-26T23:59:59.000Z

459

Masses of mesons with charm valence quarks from 2+1+1 flavor twisted mass lattice QCD  

E-Print Network (OSTI)

We present preliminary results of an ongoing lattice QCD computation of the spectrum of $D$ mesons and $D_s$ mesons and of charmonium using 2+1+1 flavors of twisted mass sea and valence quarks.

Martin Kalinowski; Marc Wagner

2013-04-30T23:59:59.000Z

460

Some topics in thermodynamics and quantum mechanics  

E-Print Network (OSTI)

We sketch some connecting relations involving fractional and quantum calculi, fractal structure, thermodynamics, and quantum mechanics.

Robert Carroll

2012-10-29T23:59:59.000Z

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


461

Quark-mass dependence of the three-flavor QCD phase diagram at zero and imaginary chemical potential: Model prediction  

Science Conference Proceedings (OSTI)

We draw the three-flavor phase diagram as a function of light- and strange-quark masses for both zero and imaginary quark-number chemical potential, using the Polyakov-loop extended Nambu-Jona-Lasinio model with an effective four-quark vertex depending on the Polyakov loop. The model prediction is qualitatively consistent with 2+1 flavor lattice QCD prediction at zero chemical potential and with degenerate three-flavor lattice QCD prediction at imaginary chemical potential.

Sasaki, Takahiro; Sakai, Yuji; Yahiro, Masanobu [Department of Physics, Graduate School of Sciences, Kyushu University, Fukuoka 812-8581 (Japan); Kouno, Hiroaki [Department of Physics, Saga University, Saga 840-8502 (Japan)

2011-11-01T23:59:59.000Z

462

Topological methods in quantum gravity.  

E-Print Network (OSTI)

??The main technical problem with background independent approaches to quantum gravity is inapplicability of standard quantum field theory methods. New methods are needed which would… (more)

Starodubtsev, Artem

2005-01-01T23:59:59.000Z

463

Quantum physics and human values  

Science Conference Proceedings (OSTI)

This report discusses the following concepts: the quantum conception of nature; the quantum conception of man; and the impact upon human values. (LSP).

Stapp, H.P.

1989-09-01T23:59:59.000Z

464

Quantum Mechanics and Black Holes  

E-Print Network (OSTI)

This paper discusses the existence of black holes from the foundations of quantum mechanics. It is found that quantum mechanics rule out a possible gravitational collapse.

Jose N. Pecina-Cruz

2005-11-11T23:59:59.000Z

465

FOURIER TRANSFORM MULTIPLE QUANTUM NMR  

E-Print Network (OSTI)

TRANSFORM MULTIPLE QUANTUM NMR G. Drobny, A. Pines, S.TRANSFO~~ MULTIPLE QUANTUM NMR G. Drobny, A. Pines, S.

Drobny, G.

2011-01-01T23:59:59.000Z

466

Quantum teleportation between remote atomic-ensemble quantum memories  

E-Print Network (OSTI)

Quantum teleportation and quantum memory are two crucial elements for large-scale quantum networks. With the help of prior distributed entanglement as a "quantum channel", quantum teleportation provides an intriguing means to faithfully transfer quantum states among distant locations without actual transmission of the physical carriers. Quantum memory enables controlled storage and retrieval of fast-flying photonic quantum bits with stationary matter systems, which is essential to achieve the scalability required for large-scale quantum networks. Combining these two capabilities, here we realize quantum teleportation between two remote atomic-ensemble quantum memory nodes, each composed of 100 million rubidium atoms and connected by a 150-meter optical fiber. The spinwave state of one atomic ensemble is mapped to a propagating photon, and subjected to Bell-state measurements with another single photon that is entangled with the spinwave state of the other ensemble. Two-photon detection events herald the succe...

Bao, Xiao-Hui; Li, Che-Ming; Yuan, Zhen-Sheng; Lu, Chao-Yang; Pan, Jian-Wei

2012-01-01T23:59:59.000Z

467

Nuclear forces from quenched and 2+1 flavor lattice QCD using the PACS-CS gauge configurations  

E-Print Network (OSTI)

Two of recent progress in lattice QCD approach to nuclear force are reported. (i) Tensor force from quenched lattice QCD: By truncating the derivative expansion of inter-nucleon potential to the strictly local terms, we obtain central force V_C(r) and tensor force V_T(r) separately from s-wave and d-wave components of Bethe-Salpeter wave function for two nucleon state with J^P=1^+. Numerical calculation is performed with quenched QCD on 32^4 lattice using the standard plaquette action at beta=5.7 with the standard Wilson quark action with kappa=0.1640, 0.1665, 0.1678. Preliminary results show that the depths of the resulting tensor force amount to 20 to 40 MeV, which is enhanced in the light quark mass region. (ii) Nuclear force from 2+1 flavor QCD with PACS-CS gauge configuration: Preliminary full QCD results are obtained by using 2+1 flavor gauge configurations generated by PACS-CS collaboration. The resulting potential has the midium range attraction of about 30 MeV similar to the preceding quenched calculations. However, the repulsive core at short distance is significantly stronger than the corresponding quenched QCD result.

N. Ishii; S. Aoki; T. Hatsuda; for PACS-CS Collaboration

2009-03-31T23:59:59.000Z

468

Quantum Zeno effect: Quantum shuffling and Markovianity  

E-Print Network (OSTI)

The behavior displayed by a quantum system when it is perturbed by a series of von Neumann measurements along time is analyzed. Because of the similarity between this general process with giving a deck of playing cards a shuffle, here it is referred to as quantum shuffling, showing that the quantum Zeno and anti-Zeno effects emerge naturally as two time limits. Within this framework, a connection between the gradual transition from anti-Zeno to Zeno behavior and the appearance of an underlying Markovian dynamics is found. Accordingly, although a priori it might result counterintuitive, the quantum Zeno effect corresponds to a dynamical regime where any trace of knowledge on how the unperturbed system should evolve initially is wiped out (very rapid shuffling). This would explain why the system apparently does not evolve or decay for a relatively long time, although it eventually undergoes an exponential decay. By means of a simple working model, conditions characterizing the shuffling dynamics have been determined, which can be of help to understand and to devise quantum control mechanisms in a number of processes from the atomic, molecular and optical physics.

A. S. Sanz; C. Sanz-Sanz; T. Gonzalez-Lezana; O. Roncero; S. Miret-Artes

2011-12-16T23:59:59.000Z

469

Quantum capacity under adversarial quantum noise: arbitrarily varying quantum channels  

E-Print Network (OSTI)

We investigate entanglement transmission over an unknown channel in the presence of a third party (called the adversary), which is enabled to choose the channel from a given set of memoryless but non-stationary channels without informing the legitimate sender and receiver about the particular choice that he made. This channel model is called arbitrarily varying quantum channel (AVQC). We derive a quantum version of Ahlswede's dichotomy for classical arbitrarily varying channels. This includes a regularized formula for the common randomness-assisted capacity for entanglement transmission of an AVQC. Quite surprisingly and in contrast to the classical analog of the problem involving the maximal and average error probability, we find that the capacity for entanglement transmission of an AVQC always equals its strong subspace transmission capacity. These results are accompanied by different notions of symmetrizability (zero-capacity conditions) as well as by conditions for an AVQC to have a capacity described by a single-letter formula. In he final part of the paper the capacity of the erasure-AVQC is computed and some light shed on the connection between AVQCs and zero-error capacities. Additionally, we show by entirely elementary and operational arguments motivated by the theory of AVQCs that the quantum, classical, and entanglement-assisted zero-error capacities of quantum channels are generically zero and are discontinuous at every positivity point.

Rudolf Ahlswede; Igor Bjelakovic; Holger Boche; Janis Noetzel

2010-10-03T23:59:59.000Z

470

Quantum motor and future  

E-Print Network (OSTI)

In a popular language, the possibilities of the Casimir expulsion effect are presented, which can be the basis of quantum motors. Such motors can be in the form of a special multilayer thin film with periodic and complex nanosized structures. Quantum motors of the type of the Casimir platforms can be the base of transportation, energy and many other systems in the future.

Evgeny G. Fateev

2013-01-20T23:59:59.000Z

471

Quantum motor and future  

E-Print Network (OSTI)

In a popular language, the possibilities of the Casimir expulsion effect are presented, which can be the basis of quantum motors. Such motors can be in the form of a special multilayer thin film with periodic and complex nanosized structures. Quantum motors of the type of the Casimir platforms can be the base of transportation, energy and many other systems in the future.

Fateev, Evgeny G

2013-01-01T23:59:59.000Z

472

QUICK QUANTUM MECHANICS ---Introduction ---  

E-Print Network (OSTI)

QUICK QUANTUM MECHANICS --- Introduction --- The following notes are intended to be a supplement to your study of Liboff's ``Introductory Quantum Mechanics.'' They are not an alternative! My purpose here of Classical Mechanics After Newton found his equations of motion, physicists knew they would have to wait

Jackson, Andrew D.

473

Quantum Physics Einstein's Gravity  

E-Print Network (OSTI)

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

Visser, Matt

474

Ultraviolet Complete Quantum Gravity  

E-Print Network (OSTI)

An ultraviolet complete (UV) quantum gravity theory is formulated in which vertex functions in Feynman graphs are entire functions and the propagating gravitons are described by local, causal propagators. A scalar-tensor action describes classical gravity theory. The cosmological constant problem is investigated in the context of the UV complete quantum gravity.

Moffat, J W

2010-01-01T23:59:59.000Z

475

Quantum Gravity and Turbulence  

E-Print Network (OSTI)

We apply recent advances in quantum gravity to the problem of turbulence. Adopting the AdS/CFT approach we propose a string theory of turbulence that explains the Kolmogorov scaling in 3+1 dimensions and the Kraichnan and Kolmogorov scalings in 2+1 dimensions. In the gravitational context, turbulence is intimately related to the properties of spacetime, or quantum, foam.

Vishnu Jejjala; Djordje Minic; Y. Jack Ng; Chia-Hsiung Tze

2010-05-18T23:59:59.000Z

476

Quantum Game Theory  

E-Print Network (OSTI)

Quantum game theory is the study of strategic behavior by agents with access to quantum technology. Broadly speaking, this technology can be employed in either of two ways: As part of a randomization device or as part of a communications protocol. We survey some of the main ideas from both branches of the subject.

Landsburg, Steven E

2011-01-01T23:59:59.000Z

477

Quantum Dots: Theory  

SciTech Connect

This review covers the description of the methodologies typically used for the calculation of the electronic structure of self-assembled and colloidal quantum dots. These are illustrated by the results of their application to a selected set of physical effects in quantum dots.

Vukmirovic, Nenad; Wang, Lin-Wang

2009-11-10T23:59:59.000Z

478

Is Quantum Search Practical?  

Science Conference Proceedings (OSTI)

Gauging a quantum algorithm's practical significance requires weighing it against the best conventional techniques applied to useful instances of the same problem. The authors show that several commonly suggested applications of Grover's quantum search algorithm fail to offer computational improvements over the best conventional algorithms.

George F. Viamontes; Igor L. Markov; John P. Hayes

2005-01-01T23:59:59.000Z

479

Quantum Democracy Is Possible  

E-Print Network (OSTI)

It is shown that, since an ultrafilter over an operator-algebraically finite (i.e. isomorphic to the lattice of projectors of a finite Von Neumann algebra) quantum logic is not necessarily principal, Arrow's Impossibility Theorem doesn't extend to the quantum case.

Gavriel Segre

2008-06-23T23:59:59.000Z

480

Quantum Spin Systems  

E-Print Network (OSTI)

This article is a short introduction to the general topic of quantum spin systems. After a brief sketch of the history of the subject, the standard mathematical framework for formulating problems and results in quantum spin systems is described. Then, three short sections are devoted to Spontaneaous Symmetry Breaking, Phase transitions, and Dynamcis.

Bruno Nachtergaele

2004-09-02T23:59:59.000Z

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481

Fractals and quantum mechanics  

Science Conference Proceedings (OSTI)

A new application of a fractal concept to quantum physics has been developed. The fractional path integrals over the paths of the Lévy flights are defined. It is shown that if fractality of the Brownian trajectories leads to standard quantum mechanics

Nick Laskin

2000-01-01T23:59:59.000Z

482

QCD THERMODYNAMICS WITH NF=2+1 NEAR THE CONTINUUM LIMIT AT REALISTIC QUARK MASSES.  

Science Conference Proceedings (OSTI)

We report on our study of QCD thermodynamics with 2 + 1 flavors of dynamical quarks. In this proceeding we present several thermodynamic quantities and our recent calculation of the critical temperature. In order to investigate the thermodynamic properties of QCD near the continuum limit we adopt improved staggered (p4) quarks coupled with tree-level Symanzik improved glue on N{sub t} = 4 and 6 lattices. The simulations are performed with a physical value of the strange quark mass and light quark masses which are in the range of m{sub q}/m{sub s} = 0.05 - 0.4. The lightest quark mass corresponds to a pion mass of about 150 MeV.

UMEDA, T.

2006-07-23T23:59:59.000Z

483

Topology across the finite temperature transition studied by overimproved cooling in gluodynamics and QCD  

E-Print Network (OSTI)

Gluodynamics and two-flavor QCD at non-zero temperature are studied with the so-called overimproved cooling technique under which caloron solutions may remain stable. We consider topological configurations either at the first occuring stable plateau of topological charge or at the first (anti)selfdual plateau and find the corresponding topological susceptibility at various temperatures on both sides of the thermal transition or crossover. In pure gluodynamics the topological susceptibility drops sharply at the deconfinement temperature while in full QCD it decreases smoothly at temperatures above the pseudocritical one. The results are close to those calculated by other methods. We interpret our findings in terms of the (in)stability of calorons with non-trivial holonomy and their dyon constituents against overimproved cooling.

V. G. Bornyakov; E. -M. Ilgenfritz; B. V. Martemyanov; V. K. Mitrjushkin; M. Muller-Preussker

2013-04-03T23:59:59.000Z

484

Topological and magnetic properties of the QCD vacuum probed by overlap fermions  

E-Print Network (OSTI)

We study some of the local CP-odd and magnetic properties of the non-Abelian vacuum with use of overlap fermions within the quenched lattice gauge theory. Among these properties are the following: inhomogeneous spatial distribution of the topological charge density (chirality for massless fermions) in SU(2) gluodynamics (for uncooled gauge configurations the chirality is localized on low-dimensional defects with d=2..3, while a sequence of cooling steps gives rise to four-dimensional instantons and hence a four-dimensional structure of the chirality distribution); finite local fluctuations of the chirality growing with the strength of an external magnetic field; magnetization and susceptibility of the QCD vacuum in SU(3) theory; magnetic catalysis of the chiral symmetry breaking, and the electric conductivity of the QCD vacuum in strong magnetic fields.

V. V. Braguta; P. V. Buividovich; T. Kalaydzhyan; M. I. Polikarpov

2013-02-26T23:59:59.000Z

485

Burgers-like equation for spontaneous breakdown of the chiral symmetry in QCD  

E-Print Network (OSTI)

We link the spontaneous breakdown of chiral symmetry in Euclidean QCD to the collision of spectral shock waves in the vicinity of zero eigenvalue of Dirac operator. The mechanism, originating from complex Burger's-like equation for viscid, pressureless, one-dimensional flow of eigenvalues, is similar to recently observed weak-strong coupling phase transition in large $N_c$ Yang-Mills theory. The spectral viscosity is proportional to the inverse of the size of the random matrix that replaces the Dirac operator in the universal (ergodic) regime. We obtain the exact scaling function and critical exponents of the chiral phase transition for the averaged characteristic polynomial for $N_c \\ge3$ QCD. We reinterpret our results in terms of known properties of chiral random matrix models and lattice data.

Jean-Paul Blaizot; Maciej A. Nowak; Piotr Warcho?

2013-03-10T23:59:59.000Z

486

Onset Transition to Cold Nuclear Matter from Lattice QCD with Heavy Quarks to $?^4$  

E-Print Network (OSTI)

We present results of our ongoing studies of an effective three-dimensional theory of thermal lattice QCD with heavy Wilson quarks. This is done by combined strong coupling and hopping parameter expansions. The full quark determinant of four dimensional lattice QCD is expanded in orders of the hopping parameter $\\kappa$, the dimensional reduction is achieved by integrating over the spatial links. We present the calculation of the effective theory through order $\\kappa^nu^m$ with $n+m=4$. This theory is then used to simulate heavy quarks near the cold and dense limit. For nonzero chemical potential the theory suffers from a sign problem, wich is avoided by employing stochastical quantisation. Continuum extrapolated results for the onset of nuclear matter are shown and the region of convergence of the effective theory is discussed.

Jens Langelage; Mathias Neuman; Owe Philipsen

2013-11-18T23:59:59.000Z

487

On the infrared freezing of perturbative QCD in the Minkowskian region  

E-Print Network (OSTI)

The infrared freezing of observables is known to hold at fixed orders of perturbative QCD if the Minkowskian quantities are defined through the analytic continuation from the Euclidean region. In a recent paper [1] it is claimed that infrared freezing can be proved also for Borel resummed all-orders quantities in perturbative QCD. In the present paper we obtain the Minkowskian quantities by the analytic continuation of the all-orders Euclidean amplitudes expressed in terms of the inverse Mellin transform of the corresponding Borel functions [2]. Our result shows that if the principle of analytic continuation is preserved in Borel-type resummations, the Minkowskian quantities exhibit a divergent increase in the infrared regime, which contradicts the claim made in [1]. We discuss the arguments given in [1] and show that the special redefinition of Borel summation at low energies adopted there does not reproduce the lowest order result obtained by analytic continuation.

Irinel Caprini; Jan Fischer

2005-05-03T23:59:59.000Z

488

Quantum scholasticism: On quantum contexts, counterfactuals, and the absurdities of quantum omniscience  

Science Conference Proceedings (OSTI)

Unlike classical information, quantum knowledge is restricted to the outcome of measurements of maximal observables corresponding to single contexts. Keywords: Context, Maximal observables, Omniscience, Quantum information

Karl Svozil

2009-02-01T23:59:59.000Z

489

Multiphoton Quantum Optics and Quantum State Engineering  

E-Print Network (OSTI)

We present a review of theoretical and experimental aspects of multiphoton quantum optics. Multiphoton processes occur and are important for many aspects of matter-radiation interactions that include the efficient ionization of atoms and molecules, and, more generally, atomic transition mechanisms; system-environment couplings and dissipative quantum dynamics; laser physics, optical parametric processes, and interferometry. A single review cannot account for all aspects of such an enormously vast subject. Here we choose to concentrate our attention on parametric processes in nonlinear media, with special emphasis on the engineering of nonclassical states of photons and atoms. We present a detailed analysis of the methods and techniques for the production of genuinely quantum multiphoton processes in nonlinear media, and the corresponding models of multiphoton effective interactions. We review existing proposals for the classification, engineering, and manipulation of nonclassical states, including Fock states...

Dell'Anno, F; Illuminati, F; 10.1016/j.physrep.2006.01.004

2009-01-01T23:59:59.000Z

490

Adiabatic Quantum Simulation of Quantum Chemistry  

E-Print Network (OSTI)

We show how to apply the quantum adiabatic algorithm directly to the quantum computation of molecular properties. We describe a procedure to map electronic structure Hamiltonians to 2-local qubit Hamiltonians with a small set of physically realizable couplings. By combining the Bravyi-Kitaev construction to map fermions to qubits with perturbative gadgets to reduce the Hamiltonian to 2-local, we obtain precision requirements on the coupling strengths and a number of ancilla qubits that scale polynomially in the problem size. Hence our mapping is efficient. The required set of controllable interactions includes only two types of interaction beyond the Ising interactions required to apply the quantum adiabatic algorithm to combinatorial optimization problems. Our mapping may also be of interest to chemists directly as it defines a dictionary from electronic structure to spin Hamiltonians with physical interactions.

Ryan Babbush; Peter J. Love; Alán Aspuru-Guzik

2013-11-15T23:59:59.000Z

491

Equation of state at finite temperature and chemical potential, lattice QCD results  

E-Print Network (OSTI)

We present an N_t=4 lattice study for the equation of state of 2+1 flavour staggered, dynamical QCD at finite temperature and chemical potential. We use the overlap improving multi-parameter reweighting technique to extend the equation of state for non-vanishing chemical potentials. The results are obtained on the line of constant physics and our physical parameters extend in temperature and baryon chemical potential upto \\approx 500-600 MeV.

F. Csikor; G. I. Egri; Z. Fodor; S. D. Katz; K. K. Szabo; A. I. Toth

2004-01-09T23:59:59.000Z

492

Phase diagram of dense quark matter in QCD-like theories  

Science Conference Proceedings (OSTI)

I report the results of a series of works on the phase diagram of theories with a different number of colors and/or quarks in a different representation than in QCD. Similarities as well as differences as compared to the real world are pointed out, focusing in particular on the interplay of confinement and chiral symmetry breaking. It will be argued that recent lattice data may provide us with a clue to understand deconfinement in cold dense quark matter.

Brauner, Tomas [Faculty of Physics, University of Bielefeld, D-33501 Bielefeld (Germany); Department of Theoretical Physics, Nuclear Physics Institute ASCR, CZ-25068 Rez (Czech Republic)

2011-05-23T23:59:59.000Z

493

Probing the phases of QCD in ultra-relativistic nuclear collisions  

E-Print Network (OSTI)

The status of RHIC theory and phenomenology is reviewed with an emphasis on the indications for the creation of a new deconfined state of matter. The critical role of high energy nuclear physics in the development of theoretical tools that address various aspects of the QCD many body dynamics is highlighted. The perspectives for studying nuclear matter under even more extreme conditions at the LHC and the overlap with high energy physics is discussed.

Ivan Vitev

2004-11-24T23:59:59.000Z

494

Next-to-leading order QCD corrections to photon production via weak-boson fusion  

E-Print Network (OSTI)

We present a calculation of next-to-leading order QCD corrections to gamma jj production via weak-boson fusion at a hadron collider in the form of a flexible parton-level Monte Carlo program which allows us to study cross sections and distributions within experimentally relevant selection cuts. The radiative corrections are found to be moderate with residual scale uncertainties being considerably improved beyond tree level. The sensitivity of the reaction to anomalous W+ W- gamma couplings is investigated.

B. Jager

2010-04-06T23:59:59.000Z

495

Next-to-leading order QCD corrections to slepton pair production via vector-boson fusion  

E-Print Network (OSTI)

Slepton pairs can be produced in vector-boson fusion processes at hadron colliders. The next-to-leading order QCD corrections to the electroweak production cross section for p p -> slepton+ slepton- +2jets at order alpha_s alpha^4 have been calculated and implemented in a NLO parton-level Monte Carlo program. Numerical results are presented for the CERN Large Hadron Collider.

Partha Konar; Dieter Zeppenfeld

2006-12-11T23:59:59.000Z

496

Quark helicity flip generalized parton distributions from two-flavor lattice QCD  

E-Print Network (OSTI)

We present an initiatory study of quark helicity flip generalized parton distributions (GPDs) in n_f=2 lattice QCD, based on clover-improved Wilson fermions for a large number of coupling constants and pion masses. Quark helicity flip GPDs yield essential information on the transverse spin structure of the nucleon. In this work, we show first results on their lowest moments and dipole masses and study the corresponding chiral and continuum extrapolations.

M. Gockeler; Ph. Hagler; R. Horsley; D. Pleiter; P. E. L. Rakow; A. Schafer; G. Schierholz; J. M. Zanotti

2005-07-01T23:59:59.000Z

497

QCD Analysis for Nuclear Parton Distributions in the Next to Leading Order  

E-Print Network (OSTI)

A QCD analysis of the nuclear parton distributions and structure functions in the NLO is performed by using the world data. By having bounded parton distributions for a nuclear with atomic number A, we can obtain the nuclear structure function in x space. Our results for nuclear structure function ratio $F^A_2 /F^D_2$ for some different values of A, are in good agreement with the experimental data. We compare our results for LO and NLO approximation.

S. Atashbar Tehrani; Ali N. Khorramian

2007-10-11T23:59:59.000Z

498

Scaling behavior and positivity violation of the gluon propagator in full QCD  

SciTech Connect

The Landau-gauge gluon propagator is studied using the coarse and fine dynamical MILC configurations. The effects of dynamical quarks are clearly visible and lead to a reduction of the nonperturbative infrared enhancement relative to the quenched case. Lattice spacing effects are studied and found to be small. The gluon spectral function is shown to clearly violate positivity in both quenched and full QCD.

Bowman, Patrick O. [Centre of Theoretical Chemistry and Physics, Institute of Fundamental Sciences, Massey University (Auckland), Private Bag 102904, NSMSC, Auckland (New Zealand); Heller, Urs M. [American Physical Society, One Research Road, Box 9000, Ridge, New York 11961-9000 (United States); Leinweber, Derek B.; Sternbeck, Andre; Smekal, Lorenz von; Williams, Anthony G. [Special Research Center for the Subatomic Structure of Matter (CSSM), Department of Physics, University of Adelaide, Adelaide 5005 (Australia); Parappilly, Maria B. [Special Research Center for the Subatomic Structure of Matter (CSSM), Department of Physics, University of Adelaide, Adelaide 5005 (Australia); School of Chemistry, Physics and Earth Sciences, Flinders University, GPO Box 2100, Adelaide 5001 (Australia); Zhang Jianbo [Department of Physics, Zhejiang University, Hangzhou, Zhejiang 310027 (China)

2007-11-01T23:59:59.000Z

499

Unveiling the cosmological QCD phase transition through the eLISA/NGO detector  

E-Print Network (OSTI)

We study the evolution of turbulence in the early universe at the QCD epoch using a state-of-the-art equation of state derived from lattice QCD simulations. Since the transition is a crossover we assume that temperature and velocity fluctuations were generated by some event in the previous history of the Universe and survive until the QCD epoch due to the extremely large Reynolds number of the primordial fluid. The fluid at the QCD epoch is assumed to be non-viscous, based on the fact that the viscosity per entropy density of the quark gluon plasma obtained from heavy-ion collision experiments at the RHIC and the LHC is extremely small. Our hydrodynamic simulations show that the velocity spectrum is very different from the Kolmogorov power law considered in studies of primordial turbulence that focus on first order phase transitions. This is due to the fact that there is no continuous injection of energy in the system and the viscosity of the fluid is negligible. Thus, as kinetic energy cascades from the larger to the smaller scales, a large amount of kinetic energy is accumulated at the smallest scales due to the lack of dissipation. We have obtained the spectrum of the gravitational radiation emitted by the motion of the fluid finding that, if typical velocity and temperature fluctuations have an amplitude $(\\Delta v) /c \\gtrsim 10^{-2}$ and/or $\\Delta T/T_c \\gtrsim 10^{-3}$, they would be detected by eLISA at frequencies larger than $\\sim 10^{-4}$ Hz.

V. R. C. Mourão Roque; G. Lugones

2013-03-27T23:59:59.000Z

500

Leading order QCD shear viscosity from the three-particle irreducible effective action  

SciTech Connect

In this article we calculate the leading order shear viscosity in QCD using the resummed three-particle irreducible effective action. We work to 3-loop order in the effective action. We show that the integral equations that resum the pinch and collinear contributions are produced naturally by the formalism. All leading order terms are included, without the need for any kind of power counting arguments.

Carrington, M. E.; Kovalchuk, E. [Department of Physics, Brandon University, Brandon, Manitoba, R7A 6A9 (Canada) and Winnipeg Institute for Theoretical Physics, Winnipeg, Manitoba (Canada)

2009-10-15T23:59:59.000Z