Black hole singularity resolution in unimodular gravity from unitarity

Abstract

We study the quantum dynamics of an interior planar AdS (anti-de Sitter) black hole, requiring unitarity in the natural time coordinate conjugate to the cosmological "constant of motion" appearing in unimodular gravity. Both the classical singularity and the horizon are replaced by a non-singular highly quantum region; semiclassical notions of spacetime evolution are only valid in an intermediate region. For the singularity, our results should be applicable to general black holes: unitarity in unimodular time always implies singularity resolution.

6 pages, 2 figures, APS style; v2: minor changes in presentation, accepted in Physical Review Letters, v3: added Mathematica notebook