Gravitational waves as waveguides

TL;DR

This paper demonstrates that gravitational waves can serve as waveguides for electromagnetic radiation, potentially altering the expected intensity decay and impacting the interpretation of gravitational-electromagnetic events.

Contribution

It introduces a Hamiltonian formalism approach to show gravitational waves can guide electromagnetic waves, with specific polarization conditions analyzed.

Findings

Electromagnetic waves aligned with gravitational waves can be guided during propagation.

Waveguiding effect can modify the inverse square law for electromagnetic intensity.

Analysis includes polarization-dependent conditions for waveguiding.

Abstract

We show that gravitational waves can act as waveguides for electromagnetic radiation, that is if the latter is initially aligned with the gravitational waves, then the alignment will survive during the propagation. The analysis is performed using the Hamiltonian formalism and the Jacobi equation for null geodesics and conditions for certain cases of polarization of the waves are obtained. The effect of waveguiding by the gravitational waves can influence the interpretation of associated gravitational and electromagnetic wave events, since the latter cannot necessarily obey the inverse square decay law for intensity.