Black hole sensitivities in Einstein-scalar-Gauss-Bonnet gravity

TL;DR

This paper computes the sensitivities of nonrotating black holes in Einstein-scalar-Gauss-Bonnet gravity, revealing how these quantities influence black hole binary dynamics and potential deviations from general relativity.

Contribution

It provides the first numerical calculations of black hole sensitivities in three classes of Einstein-scalar-Gauss-Bonnet gravity, including scalarized black holes, and compares them with analytical results.

Findings

Excellent agreement between numerical and analytical sensitivities.

Black holes in these theories exist only within a restricted parameter space.

Sensitivities can influence black hole binary evolution and stability.

Abstract

The post-Newtonian dynamics of black hole binaries in Einstein-scalar-Gauss-Bonnet theories of gravity depends on the so-called "sensitivities", quantities which characterize a black hole's adiabatic response to the time-dependent scalar field environment sourced by its companion. In this work, we calculate numerically the sensitivities of nonrotating black holes, including spontaneously scalarized ones, in three classes of Einstein-scalar-Gauss-Bonnet gravity: the shift-symmetric, dilatonic and Gaussian theories. When possible, we compare our results against perturbative analytical results, finding excellent agreement. Unlike their general relativistic counterparts, black holes in Einstein-scalar-Gauss-Bonnet gravity only exist in a restricted parameter space controlled by the theory's coupling constant. A preliminary study of the role played by the sensitivities in black hole binaries suggests that, in principle, black holes can be driven outside of their domain of existence during the inspiral, for binary parameters which we determine.