Lorentz-violating Chern-Simons action under high temperature in massless QED

TL;DR

This paper investigates Lorentz and CPT violation in massless QED at finite temperature, demonstrating that the Chern-Simons coefficient is unambiguous and that symmetry breaking intensifies at high temperatures, contrary to expectations.

Contribution

It provides a clear analysis of Lorentz and CPT violation in massless QED at high temperature, showing the unambiguous nature of the Chern-Simons coefficient and the enhancement of symmetry breaking.

Findings

No ambiguity in the Chern-Simons coefficient at high temperature

Lorentz and CPT symmetry breaking is more severe at high temperature

Contradicts the expectation of symmetry restoration at high temperature

Abstract

Lorentz and CPT violating QED with massless fermions at finite temperature is studied. We show that there is no ambiguity in the induced coefficient of the Chern-Simons-like term that defines the so-called Carroll-Field-Jackiw model at high temperature. We also show that this system constitutes an example where the breaking of CPT and Lorentz symmetries is more severe at high temperature than in the zero temperature case thus precluding any naive expectations of Lorentz symmetry restoration.