Towards a generic test of the strong field dynamics of general relativity using compact binary coalescence: Further investigations

TL;DR

This paper extends a Bayesian framework for testing the strong-field dynamics of General Relativity using compact binary coalescence, focusing on detecting small deviations in the phase evolution from multiple sources.

Contribution

It introduces a method to test individual deviation parameters in the waveform phase, improving detection of generic deviations from GR in low SNR and multi-detector scenarios.

Findings

Framework can detect small deviations in phase structure.

Numerical experiments confirm robustness against noise.

Method effectively combines information from multiple sources.

Abstract

In this paper we elaborate on earlier work by the same authors in which a novel Bayesian inference framework for testing the strong-field dynamics of General Relativity using coalescing compact binaries was proposed. Unlike methods that were used previously, our technique addresses the question whether one or more 'testing coefficients' (e.g. in the phase) parameterizing deviations from GR are non-zero, rather than all of them differing from zero at the same time. The framework is well-adapted to a scenario where most sources have low signal-to-noise ratio, and information from multiple sources as seen in multiple detectors can readily be combined. In our previous work, we conjectured that this framework can detect generic deviations from GR that can in principle not be accomodated by our model waveforms, on condition that the change in phase near frequencies where the detectors are the most sensitive is comparable to that induced by simple shifts in the lower-order phase coefficients of more than a few percent ($\sim 5$ radians at 150 Hz). To further support this claim, we perform additional numerical experiments in Gaussian and stationary noise according to the expected Advanced LIGO/Virgo noise curves, and coherently injecting signals into the network whose phasing differs structurally from the predictions of GR, but with the magnitude of the deviation still being small. We find that even then, a violation of GR can be established with good confidence.