A Simple Derivation of the Hard Thermal Loop Effective Action

TL;DR

This paper presents a straightforward derivation of the hard thermal loop effective action using the background field method and a special gauge, explicitly connecting it to the S-matrix.

Contribution

It introduces a simplified derivation of the hard thermal loop effective action by relating it directly to the S-matrix from the beginning.

Findings

Simplified derivation method for the effective action

Explicit relation to the S-matrix established

Potential for easier computations in thermal field theory

Abstract

We use the background field method along with a special gauge condition, to derive the hard thermal loop effective action in a simple manner. The new point in the paper is to relate the effective action explicitly to the S-matrix from the onset.