Scattering amplitudes and conservative dynamics at the fourth post-Minkowskian order

Abstract

We review recent progress using amplitudes methods to obtain new results for the conservative classical scattering of two massive black holes at order O( 𝐺 4 ) . We include contributions from both potential and radiation modes which effect the conservative dynamics through the tail effect. We compute the 2 → 2 scattering amplitudes and extract the radial action through the amplitude-action formula and derive the scattering angle. By matching we also obtain a Hamiltonian valid for arbitrary scattering trajectories.