Effective Action for Hard Thermal Loops in Gravitational Fields

TL;DR

This paper derives a closed-form effective action for hard thermal loops in gravitational fields using a Boltzmann equation approach, emphasizing gauge and Weyl invariance at high temperature.

Contribution

It provides the first explicit closed-form expression for the effective action of hard thermal loops in gravitational backgrounds, utilizing symmetry principles.

Findings

Explicit closed-form effective action derived

Utilizes gauge and Weyl invariance at high temperature

Provides a new approach via Boltzmann equation

Abstract

We examine, through a Boltzmann equation approach, the generating action of hard thermal loops in the background of gravitational fields. Using the gauge and Weyl invariance of the theory at high temperature, we derive an explicit closed-form expression for the effective action.