Radiatively Induced Lorentz and CPT Violation in Electrodynamics

TL;DR

This paper explores how radiative corrections in theories with Lorentz and CPT violation lead to a nonzero Chern-Simons term in electrodynamics, highlighting differences between nonperturbative and perturbative approaches.

Contribution

It clarifies the quantum generation of the Chern-Simons term in Lorentz and CPT violating electrodynamics, contrasting nonperturbative and perturbative formulations.

Findings

Nonperturbative approach yields a definite nonzero Chern-Simons term.

Perturbative approach results in an infinite class of theories with varying Chern-Simons coefficients.

Radiative corrections induce Lorentz and CPT violation effects in electrodynamics.

Abstract

In a nonperturbative formulation, radiative corrections arising from Lorentz and CPT violation in the fermion sector induce a definite and nonzero Chern-Simons addition to the electromagnetic action. If instead a perturbative formulation is used, an infinite class of theories characterized by the value of the Chern-Simons coefficient emerges at the quantum level.