Spectral Properties of Quarks at Finite Temperature in Lattice QCD

TL;DR

This paper investigates the spectral properties of quarks at finite temperature using lattice QCD, revealing two collective modes and a thermal mass proportional to temperature near the deconfinement transition.

Contribution

It introduces a two-pole ansatz to analyze quark spectral functions in lattice QCD, providing new insights into quark excitations near the critical temperature.

Findings

Quark spectral functions are well described by a two-pole ansatz.

Existence of normal and plasmino modes near the critical temperature.

Thermal quark mass is approximately proportional to temperature.

Abstract

We analyze the quark spectral function above and below the critical temperature for deconfinement and at finite momentum in quenched lattice QCD. It is found that the temporal quark correlation function in the deconfined phase near the critical temperature is well reproduced by a two-pole ansatz for the spectral function. The bare quark mass and momentum dependences of the spectral function are analyzed with this ansatz. In the chiral limit we find that even near the critical temperature the quark spectral function has two collective modes corresponding to the normal and plasmino excitations in the high temperature (T) limit. The pole mass of these modes at zero momentum, which should be identified to be the thermal mass of the quark, is approximately proportional to T in a rather wide range of T in the deconfined phase.