Causality and radiatively induced CPT violation

TL;DR

This paper investigates whether radiative corrections in Lorentz- and CPT-violating quantum electrodynamics induce a Chern-Simons-like term, concluding that causality and perturbation theory imply such a term must be absent.

Contribution

It demonstrates that, under causality and perturbation theory, radiative corrections do not generate a Lorentz- and CPT-violating Chern-Simons-like term in the gauge field.

Findings

Induced Chern-Simons-like term must be absent in the full theory.

Causality constrains radiative corrections in Lorentz- and CPT-violating QED.

Perturbation theory validity supports the absence of the term.

Abstract

We consider quantum electrodynamics with an additional Lorentz- and CPT-violating axial-vector term in the fermionic sector and discuss the possibility that radiative corrections induce a Lorentz- and CPT-violating Chern-Simons-like term for the gauge field. From the requirement of causality and the assumed validity of perturbation theory, we conclude that the induced Chern-Simons-like term must be absent in the full quantum field theory.