Gravitational Bremsstrahlung in Black-Hole Scattering at O(G^3) Linear-in-Spin Effects

Gravitational Bremsstrahlung in Black Hole Scattering at \(\mathcal{O}(G^3)\): Linear-in-Spin Effects

Authors: Lara Bohnenblust, Harald Ita, Manfred Kraus, Johannes Schlenk

Abstract: We compute the far-field time-domain waveform of the gravitational waves produced in the scattering of two spinning massive objects. The results include linear-in-spin (S) couplings and first-order gravitational corrections (G^3), and are valid for encounters in the weak-field regime. Employing a field-theory framework based on the scattering of massive scalar and vector particles coupled to Einstein-Hilbert gravity, we derive results for leading and the next-to-leading spectral waveforms. We provide analytic expressions for the required scattering data, which include trees, one-loop amplitudes and their cuts. The expressions are extracted from numerical amplitude evaluations with the Caravel program, using analytic reconstruction techniques applied in the classical limit. We confirm a recent prediction for infrared physics of the classical observable, and observe the surprising appearance of a ultraviolet singularity, which drops out in the far-field waveform.

(Bohnenblust et al., 2024)