Scattering amplitudes for Kerr black holes and higher-spin gauge symmetry

In a series of recent works it has become clear that quantum scattering amplitudes can be used to gain surprisingly useful insights to the dynamics of Kerr black holes. A simple infinite family of three-point amplitudes have been found, which describes the primary gravitational interaction of a black hole with quantum spin s. However, the corresponding Compton four-point amplitudes are not known except for a few low-spin examples. These amplitudes are needed for post-Newtonian and post-Minkowskian calculations of inspiraling binary black-hole systems. In this talk, I will show that all known Kerr amplitudes can be uniquely predicted from the principle of gauge symmetry. In particular, I will discuss the construction of a family of EFTs with Stuckelberg higher-spin fields that describe the expected dynamics of Kerr black holes. The EFTs enjoys massive higher-spin gauge symmetry, which is used as a selection principle for the non-minimal interactions. I will briefly discuss a possible interpretation of this symmetry, and why, in hindsight, it could have been anticipated.