Francesco Ferrarin: Impact of quantum gravity on the UV sensitivity of extremal black holes

Recent work has revealed that extremal Kerr black holes may exhibit a sensitivity to higher-derivative corrections to Einstein’s equations, displaying singularities in the tidal forces at the horizon. However, in a purely gravitational context, this ‘‘ultraviolet sensitivity’’ translates into a strong dependence on the Wilson coefficients in the low-energy effective field theory. These, in turn, are fixed by the underlying theory of quantum gravity in the ultraviolet. We find a prediction for these coefficients within the framework of asymptotically safe quantum gravity, and show that, if the quantum gravity scale is trans-Planckian, this horizon-scale ultraviolet sensitivity is avoided.