Gravoelectromagnetic approach to the gravitational Faraday rotation in stationary spacetimes

TL;DR

This paper demonstrates that in stationary spacetimes, the polarization plane of light near black holes experiences a rotation analogous to the Faraday effect, derived through gravoelectromagnetic formalism and applied to Kerr and NUT spacetimes.

Contribution

It introduces a gravoelectromagnetic framework to quantify gravitational Faraday rotation and derives an integral formula applicable to Kerr and NUT black hole spacetimes.

Findings

Polarization rotation proportional to gravomagnetic field component

Derived integral formula for gravitational Faraday rotation

Applied formula to Kerr and NUT spacetimes

Abstract

Using the 1+3 formulation of stationary spacetimes we show, in the context of gravoelectromagnetism, that the plane of the polarization of light rays passing close to a black hole undergoes a rotation. We show that this rotation has the same integral form as the usual Faraday effect, i.e. it is proportional to the integral of the component of the gravomagnetic field along the propagation path. We apply this integral formula to calculate the Faraday rotation induced by the Kerr and NUT spaces using the quasi-Maxwell form of the vacuum Einstein equations.