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Nuclear Theory·nucl-th

Monday·March 12, 2018

4 papers—2 primary·2 cross-listed

All4Primary2Cross-lists2
  1. 01

    [Submitted on 8 Mar 2018]

    Off-equilibrium corrections to energy and conserved charge densities in the relativistic fluid in heavy-ion collisions

    Akihiko Monnai🇫🇷

    Dissipative processes in relativistic fluids are known to be important in the analyses of the hot QCD matter created in high-energy heavy-ion collisions. In this work, I consider dissipative corrections to energy and conserved charge densities, which are conventionally assumed to be vanishing but could be finite. Causal dissipative hydrodynamics is formulated in the presence of those dissipative currents. The relation between hydrodynamic stability and transport coefficients is discussed. I then study their phenomenological consequences on the observables of heavy-ion collisions in numerical simulations. It is shown that particle spectra and elliptic flow can be visibly modified.

    Comments:
    10 pages, 5 figures; title changed, references added, conclusions unchanged
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    1803.03318 [pdf]
    PRC(2018)·11 citations
  2. 02

    [Submitted on 9 Mar 2018]

    Probing the density dependence of the symmetry energy by nucleon flow

    Xiao-Hua Fan · Gao-Chan Yong · Wei Zuo

    In the framework of the isospin-dependent Boltzmann-Uehling-Uhlenbeck transport model, sensitive regions of some nucleon observables to the nuclear symmetry energy are studied. It is found that the symmetry energy sensitive observable n/p ratio in the Sn+Sn reaction at 0.3 GeV/nucleon in fact just probes the density-dependent symmetry energy below the density of and effectively probes the density-dependent symmetry energy around or somewhat below the saturation density. Nucleon elliptic flow can probe the symmetry energy from the low-density region to the high-density region when changing the incident beam energies from 0.3 to 0.6 GeV/nucleon in the semi-central Sn+Sn reaction. And nucleon transverse and elliptic flows in the semi-central Au+Au reaction at 0.6 GeV/nucleon are more sensitive to the high-density behavior of the nuclear symmetry energy. One thus concludes that nucleon observables in the heavy reaction system and with higher incident beam energy are more suitable to be used to probe the high-density behavior of the symmetry energy. The present study may help one to get more specific information about the density-dependent symmetry energy from nucleon flow observable in heavy-ion collisions at intermediate energies.

    Comments:
    5 pages, 6 figures
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    1803.03338 [pdf]
    PRC(2018)·12 citations
  3. 03

    [Submitted on 8 Mar 2018] (cross-list from physics.comp-ph)

    A reciprocal formulation of non-exponential radiative transfer. 1: Sketch and motivation

    Eugene d'Eon

    Previous proposals to permit non-exponential free-path statistics in radiative transfer have not included support for volume and boundary sources that are spatially uncorrelated from the scattering events in the medium. Birth-collision free paths are treated identically to collision-collision free paths and application of this to general, bounded scenes with inclusions leads to non-reciprocal transport. Beginning with reciprocity as a desired property, we propose a new way to integrate non-exponential transport theory into general scenes. We distinguish between the free-path-length statistics between correlated medium particles and the free-path-length statistics beginning at locations not correlated to medium particles, such as boundary surfaces, inclusions and uncorrelated sources. Reciprocity requires that the uncorrelated free-path distributions are simply the normalized transmittance of the correlated free-path distributions. The combination leads to an equilibrium imbedding of a previously derived generalized transport equation into bounded domains. We compare predictions of this approach to Monte Carlo simulation of multiple scattering from negatively-correlated suspensions of monodispersive hard spheres in bounded two-dimensional domains and demonstrate improved performance relative to previous work. We also derive new, exact, reciprocal, single-scattering solutions for plane-parallel half-spaces over a variety of non-exponential media types.

    Comments:
    16 pages, addressed reviewer comments
    Subjects:
    Computational Physics (physics.comp-ph); cs.GR (cs.GR); Nuclear Theory (nucl-th)
    arXiv:
    1803.03259 [pdf]
    1 citation
  4. 04

    [Submitted on 8 Mar 2018] (cross-list from quant-ph)

    Quantum-Classical Computation of Schwinger Model Dynamics using Quantum Computers

    N. Klco🇺🇸 · E. F. Dumitrescu🇺🇸 · A. J. McCaskey🇺🇸 · T. D. Morris🇺🇸 · R. C. Pooser🇺🇸 · M. Sanz🇪🇸 · E. Solano🇪🇸 · P. Lougovski🇺🇸 · M. J. Savage🇺🇸

    We present a quantum-classical algorithm to study the dynamics of the two-spatial-site Schwinger model on IBM's quantum computers. Using rotational symmetries, total charge, and parity, the number of qubits needed to perform computation is reduced by a factor of , removing exponentially-large unphysical sectors from the Hilbert space. Our work opens an avenue for exploration of other lattice quantum field theories, such as quantum chromodynamics, where classical computation is used to find symmetry sectors in which the quantum computer evaluates the dynamics of quantum fluctuations.

    Comments:
    5 pages, 4 figures, 23 pages supplemental, 8 figures supplemental
    Subjects:
    Quantum Physics (quant-ph); High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
    arXiv:
    1803.03326 [pdf]
    PRA(2018)·515 citations

Affiliations

first authorsco-authorsvia INSPIRE