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

Abstract

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 Nf=2+1 fermion flavors in the medium. For the computation of real-time spectra, we deploy the recent Bayesian Reconstruction (BR) method and develop a new prior in order to better assess the inherent systematic uncertainties. We identify the quark quasiparticle spectrum and analyze the (non)appearance of zero modes at or around the pseudocritical temperature. In both, the fully unquenched system and a simpler truncation, using a model for the gluon propagator, we observe a characteristic two-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 pseudocritical transition temperature.