Black hole singularity resolution in unimodular gravity from unitarity

TL;DR

This paper demonstrates that in unimodular gravity, enforcing unitarity in the quantum dynamics of black holes replaces classical singularities and horizons with non-singular quantum regions, suggesting a universal resolution of singularities.

Contribution

It shows that unitarity in unimodular gravity leads to the resolution of black hole singularities and horizons, providing a new quantum perspective on black hole interiors.

Findings

Classical singularity replaced by a quantum region

Horizon is also replaced by a non-singular quantum zone

Unitarity implies universal singularity resolution in black holes

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.