Tidal excitation as mixing in thermal CFT

Abstract

We use mixed correlators in thermal CFT as clean probes of the strong gravity effects in their holographic duals. The dual interpretation of mixing is an inelastic conversion of one field to another field, induced by gravity: tidal excitation. We find an enhanced mixing at high temperatures, corresponding to large AdS black holes, concentrated to small boundary momenta, dual to the deep bulk, where strong gravitational fields are expected. We also find large $\mathcal{O}(1/G_{N})$ tidal conversion in the low temperature phase of the $U(N)$ vector model, strengthening suspicions that the bulk dual of this phase also houses extremely compact objects.