Bounds on the charge of the graviton using gravitational wave observations

TL;DR

This paper establishes the first bounds on the graviton's electric charge by analyzing gravitational wave data, using phase modifications and the Aharonov-Bohm effect, setting constraints orders of magnitude tighter than previous limits.

Contribution

It introduces the first constraints on the graviton's charge using gravitational wave observations, combining phase evolution analysis and Aharonov-Bohm effect considerations.

Findings

Upper limit on graviton charge: |q_g|/e < 3×10^{-34} from mass bounds

Phase difference constraint: |q_g|/e < 2×10^{-26} from GW190814

First-ever bounds on graviton charge from GW data

Abstract

If the graviton possesses a non-zero charge $q_g$, gravitational waves (GW) originating from astrophysical sources would experience an additional time delay due to intergalactic magnetic fields. This would result in a modification of the phase evolution of the observed GW signal similar to the effect induced by a massive graviton. As a result, we can reinterpret the most recent upper limits on the graviton's mass as constraints on the joint mass-charge parameter space, finding $|q_g|/{e} < 3\times 10^{-34}$ where $e$ represents the charge of an electron. Additionally, we illustrate that a charged graviton would introduce a constant phase difference in the gravitational waves detected by two spatially separated GW detectors due to the Aharonov-Bohm effect. Using the non-observation of such a phase difference for the GW event GW190814, we establish a mass-independent constraint $|q_g|/e < 2\times 10^{-26}$. To the best of our knowledge, our results constitute the first-ever bounds on the charge of the graviton. We also discuss various caveats involved in our measurements and prospects for strengthening these bounds with future GW observations.