Abstract

Tidal deformability coefficients (“Love numbers”) are key parameters of compact objects, which can be probed with gravitational wave measurements. Also they are Wilson coefficients of the effective field theory (EFT) of inspiraling binaries. Remarkably, black hole Love numbers vanish identically in general relativity in four dimensions, which represents a major naturalness problem in the EFT context. In my talk, I will present a new hidden SL(2,R)xU(1) symmetry of general relativity (“Love symmetry”), which elegantly resolves the naturalness paradox. In particular, I will demonstrate that all known properties of black hole tidal Love numbers follow from the SL(2,R) representation theory. Finally, I will discuss implications of the Love symmetry for gravitational wave science and its relation to near-horizon isometries of extremal black holes.