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Nuclear Theory·nucl-th

Wednesday·May 10, 2017

9 papers—7 primary·2 cross-listed

All9Primary7Cross-lists2
  1. 08

    [Submitted on 9 May 2017] (cross-list from hep-ph)

    Bayesian analysis of quark spectral properties from the Dyson-Schwinger equation

    Christian S. Fischer🇩🇪 · Jan M. Pawlowski🇩🇪 · Alexander Rothkopf🇩🇪 · Christian A. Welzbacher🇩🇪

    We report results on the quark spectral function in the Landau gauge at finite temperature determined from its Dyson-Schwinger equation. Compared to earlier quenched results this study encompasses unquenched fermion flavors in the medium. For the reconstruction of real-time spectra we deploy a recent Bayesian approach (BR method) and develop a new prior in order to better assess the inherent systematic uncertainties. We identify the quark quasi-particle spectrum and analyze the (non-)appearance of zero modes at or around the pseudo-critical temperature. In both, the fully unquenched system and a simpler truncation using a model for the gluon propagator we observe a characteristic three-peak structure at zero three-momentum. The temperature dependence of these structures in case of the gluon propagator model is different than observed in previous studies. For the back-coupled and unquenched case we find interesting modifications at and around the pseudo-critical transition temperature.

    Comments:
    18 pages, 21 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1705.03207 [pdf]
    PRD(2018)·40 citations
  2. 09

    [Submitted on 9 May 2017] (cross-list from hep-th)

    Phase structure of NJL model with weak renormalization group

    Ken-Ichi Aoki🇯🇵 · Shin-Ichiro Kumamoto🇯🇵 · Masatoshi Yamada🇩🇪

    We analyze the chiral phase structure of the Nambu--Jona-Lasinio model at finite temperature and density by using the functional renormalization group (FRG). The renormalization group (RG) equation for the fermionic effective potential is given as a partial differential equation, where and is a dimensionless RG scale. When the dynamical chiral symmetry breaking (DSB) occurs at a certain scale , has singularities originated from the phase transitions, and then one cannot follow RG flows after . In this study, we introduce the weak solution method to the RG equation in order to follow the RG flows after the DSB and to evaluate the dynamical mass and the chiral condensate in low energy scales. It is shown that the weak solution of the RG equation correctly captures vacuum structures and critical phenomena within the pure fermionic system. We show the chiral phase diagram on temperature, chemical potential and the four-Fermi coupling constant.

    Comments:
    32 pages, 12 figures; Version published in Nuclear Physics B
    Subjects:
    High Energy Physics — Theory (hep-th); Statistical Mechanics (cond-mat.stat-mech); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1705.03273 [pdf]
    NPB(2018)·33 citations

Affiliations

first authorsco-authorsvia INSPIRE