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Nuclear Theory·nucl-th

Wednesday·December 24, 2014

6 papers—2 primary·4 cross-listed

All6Primary2Cross-lists4
  1. 03

    [Submitted on 22 Dec 2014] (cross-list from cond-mat.quant-gas)

    Tunneling Theory for Tunable Open Quantum Systems of Ultracold Atoms in One-Dimensional Traps

    R. Lundmark · C. Forssén · J. Rotureau

    The creation of tunable open quantum systems is becoming feasible in current experiments with ultracold atoms in low-dimensional traps. In particular, the high degree of experimental control over these systems allows detailed studies of tunneling dynamics, e.g., as a function of the trapping geometry and the interparticle interaction strength. In order to address this exciting opportunity we present a theoretical framework for two-body tunneling based on the rigged Hilbert space formulation. In this approach, bound, resonant and scattering states are included on an equal footing, and we argue that the coupling of all these components is vital for a correct description of the relevant threshold phenomena. In particular, we study the tunneling mechanism for two-body systems in one-dimensional traps and different interaction regimes. We find a strong dominance of sequential tunneling of single particles for repulsive and weakly attractive systems, while there is a signature of correlated pair tunneling in the calculated many-particle flux for strongly attractive interparticle interaction.

    Comments:
    To be published in Phys. Rev. A (Rapid Communication)
    Subjects:
    Quantum Gases (cond-mat.quant-gas); Nuclear Theory (nucl-th)
    arXiv:
    1412.7175 [pdf]
    PRA(2015)·18 citations
  2. 04

    [Submitted on 23 Dec 2014] (cross-list from hep-lat)

    Effects of near-zero Dirac eigenmodes on axial U(1) symmetry at finite temperature

    Akio Tomiya🇯🇵 · Guido Cossu🇯🇵 · Hidenori Fukaya🇯🇵 · Shoji Hashimoto🇯🇵 · Junichi Noaki🇯🇵

    We study the axial U(1)A symmetry of Nf = 2 QCD at finite temperature using the Dirac eigenvalue spectrum. The gauge configurations are generated employing the Mobius domain-wall fermion action on 16^3x8 and 32^3x8 lattices. The physical spatial size of these lattices is around 2 fm and 4 fm, respectively, and the simulated temperature is around 200 MeV, which is slightly above the critical temperature of the chiral phase transition. Although the Mobius domain-wall Dirac operator is expected to have a good chiral symmetry and our data actually show small values of the residual mass, we observe significant violation of the Ginsparg-Wilson relation for the low- lying eigenmodes of the Mobius domain-wall Dirac operator. Using the reweighting technique, we compute the overlap-Dirac operator spectrum on the same set of configurations and find a significant difference of the spectrum between the two Dirac operators for the low-lying eigenvalues. The overlap-Dirac spectrum shows a gap from zero, which is insensitive to the spacial volume.

    Comments:
    7pages, 8 figures, contribution to the The 32nd International Symposium on Lattice Field Theory, 23-28 June, 2014, Columbia University New York, NY
    Subjects:
    High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1412.7306 [pdf]
    PoS(2015)·20 citations
  3. 05

    [Submitted on 23 Dec 2014] (cross-list from hep-ex)

    J/ measurements in the STAR experiment

    Barbara Trzeciak (for the STAR Collaboration)🇨🇿

    In this paper, we present recent STAR J/ results. J/ nuclear modification factors () in Au+Au collisions at 200, 62.4 and 39 GeV and in U+U collisions at 193 GeV are measured and compared to different theoretical calculations. We also report J/ elliptic flow () results in Au+Au collisions at 200 GeV and the first to J/ ratio measurement in collisions at 500 GeV.

    Comments:
    2 pages, 4 figures, Proceedings for the 18th Conference of Czech and Slovak Physicists, Olomouc, Czech Republic, September 16-19, 2014
    Subjects:
    High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
    arXiv:
    1412.7345 [pdf]
    1 citation
  4. 06

    [Submitted on 23 Dec 2014] (cross-list from hep-ph)

    Correlations between light and heavy flavors near the chiral crossover

    Chihiro Sasaki🇩🇪 · Krzysztof Redlich🇵🇱

    Thermal fluctuations and correlations between the light and heavy-light mesons are explored within a chiral effective theory implementing heavy quark symmetry. We show, that various heavy-light flavor correlations indicate a remnant of the chiral criticality in a narrow range of temperature where the chiral susceptibility exhibits a peak structure. The onset of the chiral crossover, in the heavy-light flavor correlations, is therefore independent from the light flavors. This indicates that the fluctuations carried by strange charmed mesons can also be used to identify the chiral crossover, which is dominated by the non-strange light quark dynamics.

    Comments:
    6 pages, 4 figures; v2) references added, discussions expanded though the main statement unchanged
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1412.7365 [pdf]
    PRD(2015)·8 citations

Affiliations

first authorsco-authorsvia INSPIRE