WQFT group seminar.

Speaker: Oliver Long

Title: Black hole scattering in the strong-field regime: Merging post-Minkowskian theory with numerical methods

Abstract: Recent advances in modelling unbound binary black hole interactions have been driven by the application of scattering amplitude methods to generate results within the post-Minkowskian (PM) expansion. However, this expansion breaks down when approaching the strong-field where the large curvature effects become non-negligible. In this talk, I will show how numerical information from self-force (SF), an expansion in the small mass ratio of the system, can inform higher-order coefficients in the PM expansion. I will also show how a single point of SF scattering data can be used to resum the PM series, providing accurate predictions for scattering angles across all separations. Additionally, I will present results from unbound numerical relativity simulations, where the full Einstein field equations are solved for comparable mass systems, and compare these with predictions from PM-informed effective one body models.