Observation of Gravitational Waves by Invariants for Electromagnetic Waves

TL;DR

This paper develops a theoretical framework for detecting gravitational waves through their effects on electromagnetic waves by analyzing gauge-invariant electromagnetic invariants, providing a new approach for GW observation.

Contribution

It introduces a full electromagnetic analysis of GW effects without optical approximation, focusing on gauge-invariant invariants for GW detection.

Findings

Derived analytic expressions for electromagnetic invariant perturbations caused by GWs.

Proposed a GW detector method based on measuring electromagnetic invariants.

Presented antenna patterns for monochromatic GWs and EMWs.

Abstract

We lay a theoretical foundation in the observation of gravitational waves (GWs) by electromagnetic waves (EMWs) performing a full electromagnetic analysis without any optical approximation. For that, the perturbation of plane EMWs is obtained by solving the perturbed Maxwell equation with GWs in the Minkowski background spacetime. In a GW detector using the EMWs, we propose to measure the electromagnetic invariants that are independent of the motion of the EMW receiver and whose perturbations are gauge-invariant. Imposing a physical boundary condition at EMW emitters, we have analytic results for the perturbations of invariants that can be measured in the EMW receiver. Finally, we show antenna patterns of the detector with monochromatic plane GWs and EMWs.