Absorption with amplitudes
Gravitational partial-wave absorption from scattering amplitudes
Gravitational-wave data has sparked theorists to develop new methods in general relativity. Many use scattering amplitudes to study conservative black-hole interactions. We present the first study of non-conservative gravitational-wave absorption using on-shell scattering amplitudes. In the process, we develop a novel covariant approach to spin-weighted spherical harmonics, which has applications both in and beyond GR.