Gravitational ringing of rotating black holes in higher-derivative gravity

TL;DR

This paper investigates how higher-derivative gravity corrections influence the gravitational ringing and quasinormal modes of slowly-rotating black holes, providing results relevant for future gravitational wave data analysis.

Contribution

It derives coupled Schrödinger-like equations for perturbations in higher-derivative gravity and computes shifts in quasinormal mode frequencies at linear order in spin.

Findings

Coupled equations govern odd and even parity perturbations.

Higher-derivative corrections cause measurable shifts in quasinormal modes.

Parity-violating terms influence mode coupling and frequencies.

Abstract

We study gravitational perturbations of slowly-rotating black holes in a general effective-field-theory extension of general relativity that includes up to eight-derivative terms. We show that two Schr\"odinger-like equations with spin-dependent effective potentials govern the odd - and even-parity master variables. These equations are coupled for parity-violating corrections, and this coupling affects the quasinormal modes even at linear order in the higher-derivative corrections, due to their isospectrality in general relativity. We provide results for the shifts in the fundamental quasinormal mode frequencies at linear order in the spin, which we expect to be valuable for high-precision phenomenology through future gravitational wave observations.