Gravitational Faraday Holonomy (2501.07483v2)

Abstract: Closed optical trajectories in Kerr spacetime are engineered to exhibit a marked lack of symmetry. The eccentricity manifests as a holonomy in gravitational Faraday rotation that can be made arbitrarily large by radial translation of the common location of source and receiver. All trajectories are non-equatorial and include a passage through the equatorial plane at the radial turning point, where the trajectory and pseudo-magnetic field are well-aligned. This, combined with path asymmetry, results in a large gravitational Faraday holonomy that lends itself to experimental measurement. Trajectories that start further away from the singularity pass more closely to the ergosphere, thus transiting a more distorted region of spacetime with concomitant amplification of gravitational Coriolis force.