Carlo Heissenberg, Angular Momentum Loss Due to Tidal Effects in the Post-Minkowskian Expansion 

ITMP seminar, Nov 30, 2022
Abstract: The steadily increasing sensitivity of gravitational-wave measurements challenges the state of the art of precision calculations for gravitational collisions. In this context, scattering amplitudes have contributed to the advance of the precision frontier in the Post-Minkowskian (PM) expansion, based on successive approximations labeled by powers of Newton's constant G and valid for generic velocities. In this talk, based on arXiv:2210.15689, I will illustrate the calculation of tidal corrections to the loss of angular momentum in a two-body collision at leading Post-Minkowskian order from an amplitude-based approach. The eikonal operator allows us to efficiently combine elastic and inelastic amplitudes, and captures both the contributions due to genuine gravitational-wave emissions and those due to the static gravitational field. We calculate the former by harnessing powerful collider-physics techniques such as reverse unitarity, thereby reducing them to cut two-loop integrals. For the latter, we can employ the results of arXiv:2203.11915 where static-field effects were calculated for generic gravitational scattering events using the leading soft graviton theorem.