Geometric optics analysis in Lorentz violating Chern-Simons electrodynamics

TL;DR

This paper investigates how Lorentz-violating Chern-Simons terms affect light propagation in geometric optics, revealing polarization changes without altering light intensity, with implications for astrophysical observations.

Contribution

It provides a detailed analysis of the geometric optics limit in Lorentz-violating Chern-Simons electrodynamics, highlighting polarization effects absent in intensity modifications.

Findings

Polarization of light can be affected by the Chern-Simons term.

Light intensity remains unaffected by the Lorentz-violating term.

Photon polarization may change during propagation from astrophysical sources.

Abstract

We study the geometric optics limit of the electrodynamics in the presence of Lorentz violating Chern-Simons term in (3+1) dimensions. The Chern-Simons term couples the dual electromagnetic tensor to an external four-vector and the electromagnetic gauge field. For a fixed external four-vector, such a Chern-Simons term violates Lorentz invariance while maintaining the gauge invariance of the theory. In this analysis, we look into the consequences of Lorentz symmetry violating Chern-Simons term within the geometric optics limit of light rays propagating from a source to an observation point. We argue that the Ricci tensor and the Lorentz-violating term modify the dynamical equation for the gauge vector field. However, in the geometric optics limit, neither the space-time curvature nor the Chern-Simons term influences the intensity of light. Unlike the intensity, the polarization of light, on the other hand, can be influenced by the Lorentz-violating Chern-Simons term. Due to such an effect in the presence of Chern-Simons term, the photon emitting from astrophysical objects can undergo a change in polarization as it propagates in space.