Searches for Anisotropic Lorentz-Invariance Violation in the Photon Sector

TL;DR

This paper discusses astrophysical methods used to search for tiny deviations from Lorentz invariance in the photon sector, which could indicate new physics beyond current theories, by analyzing photon dispersion and birefringence over large cosmic distances.

Contribution

It introduces novel astrophysical techniques to constrain Lorentz invariance violation in the photon sector, focusing on anisotropic effects.

Findings

Constraints on photon dispersion relations

Limits on vacuum birefringence effects

No evidence of Lorentz violation found

Abstract

Lorentz invariance, the fundamental symmetry of Einstein's theory of Special Relativity, has been established and tested by many classical and modern experiments. However, many theories that unify the Standard Model of particle physics and General Relativity predict a violation of Lorentz invariance at the Planck scale. While this energy range cannot be reached by current experiments, minute deviations from Lorentz symmetry may be present at lower energies. Astrophysical experiments are very suitable to search for these deviations, since their effects accumulate as photons travel across large distances. In this paper, we describe astrophysical methods that we used to constrain the photon dispersion and vacuum birefringence.