Maxwell-Chern-Simons theory for curved spacetime backgrounds

TL;DR

This paper explores a modified electrodynamics theory with a photonic Chern-Simons term in curved spacetime, revealing new light propagation effects such as stable bounded orbits and polarization-dependent gravitational redshifts.

Contribution

It introduces a novel four-dimensional electrodynamics model with a Chern-Simons-like term and analyzes its implications for light propagation in curved spacetime backgrounds.

Findings

Existence of stable bounded light orbits in Schwarzschild spacetime

Polarization modes experience different gravitational redshifts

Modified light paths lead to new observable effects

Abstract

We consider a modified version of four-dimensional electrodynamics, which has a photonic Chern-Simons-like term with spacelike background vector in the action. Light propagation in curved spacetime backgrounds is discussed using the geometrical-optics approximation. The corresponding light path is modified, which allows for new effects. In a Schwarzschild background, for example, there now exist stable bounded orbits of light rays and the two polarization modes of light rays in unbounded orbits can have different gravitational redshifts. An Erratum with important corrections has been published, which appears as Appendix E in this arXiv version.