Probing quadratic gravity with black-hole ringdown gravitational waves measured by LIGO-Virgo-KAGRA detectors

TL;DR

This paper uses gravitational-wave ringdown signals from black holes detected by LIGO-Virgo-KAGRA to set the first constraints on quadratic gravity theories, finding no deviations from general relativity and limiting the coupling scales of several models.

Contribution

It provides the first observational constraints on quadratic gravity theories using black-hole ringdown spectra from gravitational-wave data.

Findings

No quadratic-gravity signatures detected in ringdown signals.

Constraints on coupling length scales: axi-dilaton gravity < 34 km, Chern-Simons gravity < 49 km, Gauss-Bonnet gravity < 47 km.

First constraints derived purely from quasinormal-mode spectra.

Abstract

Quadratic gravity theories emerge as the low-energy limit of many grand-unified and quantum-gravity theories. We report the first gravitational-wave ringdown constraints on such theories obtained purely from the quasinormal-mode spectra of rapidly-spinning black-hole remnants. We find no quadratic-gravity signatures from ringdown signals measured by the LIGO-Virgo-KAGRA detectors, thereby constraining the coupling length scale of axi-dilaton gravity below 34 km, dynamical Chern-Simons gravity below 49 km, and scalar Gauss-Bonnet gravity below 47 km.