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

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 Einsteinscalar-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.

Extreme mass-ratio inspirals as probes of scalar fields: Eccentric equatorial orbits around Kerr black holes

“…Therefore, all changes in the EMRI evolution given by the extra scalar field are uniquely and universally specified by the value of d. For many gravity theories, the latter can be uniquely mapped to the theoretical parameters which control deviations from GR. In such cases, future measurements of d with LISA observations, can be translated to constraints on the fundamental parameters that characterize beyond GR theories [19,80]. These results have important consequences.…”

Black-hole ringdown as a probe of higher-curvature gravity theories

“…First, the presence of the scalar charge implies that when in binaries, BHs can source scalar-dipole radiation (see, e.g., Refs. [77][78][79][80][81]) which affects the GW phase at −1PN order (relative to the dominant quadrupolar GR contribution), with magnitude proportional to the difference between the charges of binary components. This makes EdGB gravity testable with GW observations of compact binaries where at least one component is a BH.…”

Extreme mass-ratio inspirals as probes of scalar fields: eccentric equatorial orbits around Kerr black holes

“…Therefore, all changes in the EMRI evolution given by the extra scalar field are uniquely and universally specified by the value of d. For many gravity theories, the latter can be uniquely mapped to the theoretical parameters which control deviations from GR. In such cases, future measurements of d with LISA observations, can be translated to constraints on the fundamental parameters that characterize beyond GR theories [19,79]. These results have important consequences.…”