Comment on fermion propagator in real-time quantum-field theory at finite temperature and density

TL;DR

This paper examines different forms of the fermion propagator at finite temperature and density, highlighting that the standard form fails in certain QCD Green functions involving diquark condensation, while an alternative form remains valid.

Contribution

It clarifies which form of the fermion propagator is appropriate for hot and dense QCD calculations involving diquark operators.

Findings

Standard fermion propagator form does not work with diquark-condensation Green functions.

An alternative fermion propagator form is suitable in these conditions.

Provides guidance for correct propagator usage in finite-temperature QCD studies.

Abstract

Two forms are available for the fermion propagator at finite temperature and density. It is shown that, when one deals with a diquark-condensation-operator inserted Green function in hot and dense QCD, the standard form of the quark propagator does not work. On the other hand, another form of the quark propagator does work.