Factorization of finite temperature graphs in thermal QED

TL;DR

This paper introduces a thermal operator approach that simplifies the calculation of Feynman graphs in finite temperature and chemical potential QED, revealing new factorization properties of self-energies.

Contribution

It presents a novel thermal operator method that relates finite temperature graphs to zero temperature graphs with chemical potential, simplifying computations in thermal QED.

Findings

Factorization of finite temperature graphs using the thermal operator

Simplified relation between finite temperature and zero temperature graphs with chemical potential

Insights into thermal photon and fermion self-energies

Abstract

We extend our previous analysis of gauge and Dirac fields in the presence of a chemical potential. We consider an alternate thermal operator which relates in a simple way the Feynman graphs in QED at finite temperature and charge density to those at zero temperature but non-zero chemical potential. Several interesting features of such a factorization are discussed in the context of the thermal photon and fermion self-energies.