Evaluating transport coefficients in real time thermal field theory

TL;DR

This paper develops a real-time formulation approach to calculate transport coefficients in a hadronic gas, providing an alternative to the traditional imaginary time method and potentially enabling more direct real-time analysis.

Contribution

It introduces a real-time formulation method for evaluating transport coefficients, advancing beyond the conventional imaginary time approach.

Findings

Successfully relates retarded and time-ordered correlation functions in real time

Provides a perturbative evaluation of correlation functions in real time

Offers a framework for real-time calculation of transport coefficients

Abstract

Transport coefficients in a hadronic gas have been calculated earlier in the imaginary time formulation of thermal field theory. The steps involved are to relate the defining retarded correlation function to the corresponding time-ordered one and to evaluate the latter in the conventional perturbation expansion. Here we carry out both the steps in the real time formulation.