Nonlinear curvature effects in gravitational waves from inspiralling black hole binaries

Abstract

Gravitational waves (GWs) from merging black holes allow for unprecedented probes of strong-field gravity. Testing gravity in this regime requires accurate predictions of gravitational waveform templates in viable extensions of general relativity. We concentrate on scalar Gauss-Bonnet gravity, one of the most compelling classes of theories appearing as the low-energy limit of quantum gravity paradigms, which introduces quadratic curvature corrections to gravity coupled to a scalar field and allows for black hole solutions with scalar charge. Focusing on inspiraling black hole binaries, we compute the leading-order corrections due to curvature nonlinearities in the GW and scalar waveforms, showing that the new contributions, beyond merely the effect of scalar field, appear at first post-Newtonian order in GWs. We provide ready-to-implement GW polarizations and phasing. Computing the GW phasing in the Fourier domain, we perform a parameter-space study to quantify the detectability of deviations from general relativity. Our results lay important foundations for future precision tests of gravity with both parametrized and theory-specific searches.

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

“…The PN dynamics of black hole binaries in ESGB gravity was studied in Refs. [43,[47][48][49] in the weak-field, slow orbital velocity limit. In this context, Refs.…”

“…With this motivation, considerable effort has been placed in developing tools to model the dynamics of black hole binaries in ESGB gravity, including the prediction of gravitational waveforms, using both post-Newtonian (PN) [43,[47][48][49][50] and numerical relativity [51][52][53][54][55][56][57][58][59] approaches, the latter accompanied by works studying the…”

Compact Objects in Alternative Gravities

“…The presence of the scalar field breaks isospectrality of the modes. Recent developments concern the perturbative inclusion of rotation for QNMs [96], and time evolution of the gravitational wave signal [97,98].…”

Tensor-Multi-Scalar Gravity: Equations of Motion to 2.5 post-Newtonian Order

“…where we sum over the various bodies A (not to be conflicted with the conformal factor A = A(ϕ)), and m A = m A (ϕ) denotes the Einstein-frame masses of the objects corresponding to the worldlines z µ A . In the matter action (78) it is taken into account that the mass of self-gravitating objects m A can depend explicitly on the scalar fields, i.e. to have a compact objects such as neutron star or a black hole endowed with scalar hair.…”

“…More recently, Bernard studied in a series [70][71][72] the equations of motion in STT to 3 PN order, the resulting conserved quantities and the dipolar tidal effects.The PN expansion and the related gravitational waveforms up to different orders were studied also in other alternative theories of gravity, e.g. massive STT, Gauss-Bonnet gravity, Chern-Simons theories [73][74][75][76][77][78][79][80].…”