Fundamental physics using the temporal gravitational wave background

TL;DR

This paper introduces a new method to probe fundamental physics by analyzing temporal correlations between electromagnetic signals and gravitational wave backgrounds from binary mergers, enabling insights into cosmology and gravitation.

Contribution

It proposes using time delays between EM and GW signals as a standard clock to measure source redshifts and test fundamental physics across cosmological distances.

Findings

Potential to detect EM counterparts to sub-threshold GW signals.

Ability to measure source redshifts via time delay dilation.

New tests of gravitation and fundamental physics at high redshifts.

Abstract

We propose a novel probe of fundamental physics that involves the exploration of temporal correlations between the multi-frequency electromagnetic (EM) signal and the sub-threshold GW signal or stochastic gravitational wave background (SGWB) originating from coalescing binaries. This method will be useful for the detection of EM counterparts associated with the sub-threshold/SGWB signal. Exploiting the time delay between concomitant emission of the gravitational wave and EM signals enables inference of the redshifts of the contributing sources by studying the time delay dilation due to cosmological expansion, provided that the time-lag between the emission of gravitational wave signal and the EM signal acts like a standard clock. Measurement of the inevitable time-domain correlations between different frequencies of gravitational and EM waves, most notably in gamma-rays, will test several aspects of fundamental physics and gravitation theory, and enable a new pathway for current and future gravitational wave telescopes to study the universal nature of binary compact objects to high redshifts.