“Gravitational Raman Scattering and Black Hole Naturalness”
Recent progress in gravitational wave astronomy has spurred the development of precision theoretical tools to describe gravitational binary dynamics. One such tool is classical worldline effective field theory (EFT), which builds a perturbative expansion of the gravitational field from binary components starting from the point particle limit. The Wilson coefficients of this EFT capture induced tidal deformations of compact objects, and provide a generalization to the tidal Love numbers of Newtonian gravity.
In the first part of my talk, I will show how these coefficients can be determined from scattering amplitudes of the gravitational Raman process, a quasi-elastic scattering of waves off compact objects. I will then show that the worldline EFT exhibits strong fine-tuning when applied to black holes, which gives rise to a naturalness paradox associated with the vanishing of black hole static Love numbers. In the second part of the talk, I will present a new hidden symmetry of black holes (Love symmetry) that resolves this paradox. Finally, I will briefly discuss experimental applications of the worldline EFT to the searches of exotic compact objects in the LIGO/Virgo/KAGRA gravitational wave data.
Host: Walter Goldberger