Quasifermion spectrum at finite temperature from coupled Schwinger-Dyson equations for a fermion-boson system

TL;DR

This study nonperturbatively analyzes the fermion spectrum at finite temperature in a chiral invariant model, revealing a stable three-peak structure in the spectrum even under strong coupling conditions.

Contribution

It develops and solves coupled Schwinger-Dyson equations in real time, demonstrating the robustness of the three-peak fermion spectrum beyond one-loop approximations.

Findings

Fermion spectrum exhibits a three-peak structure at finite temperature.

The three-peak structure remains stable under strong coupling.

Higher order corrections do not eliminate the three-peak feature.

Abstract

We nonperturbatively investigate a fermion spectrum at finite temperature in a chiral invariant linear sigma model. Coupled Schwinger-Dyson equations for fermion and boson are developed in the real time formalism and solved numerically. From the coupling of a massless fermion with a massive boson, the fermion spectrum shows a three-peak structure at some temperatures even for the strong coupling region. This means that the three-peak structure which was originally found in the one-loop calculation is stable against higher order corrections even in the strong coupling region.