Speaker
Roberto Emparan
(ICREA & U Barcelona)
Description
Recent developments have revealed that black holes near extremality exhibit large quantum fluctuations in their geometry, marking a controllable breakdown of semiclassical quantum field theory in curved spacetime. I will discuss how these fluctuations can be probed through their response to external perturbations. In wave scattering, extremely cold black holes look larger when probed with scalar fields, but become transparent to low-frequency light or gravitational radiation. They also acquire non-zero tidal deformability (Love numbers), whereas classical black holes have vanishing Love numbers. Although such signatures are extraordinarily hard to detect, they provide concrete probes of quantum gravity in near-extremal regimes.