Towards conditions for black-hole singularity-resolution in asymptotically safe quantum gravity

TL;DR

This paper investigates whether quantum gravity effects can resolve black hole singularities by analyzing the impact of running gravitational couplings and cosmological constant within asymptotic safety, suggesting conditions for singularity removal.

Contribution

It introduces a framework incorporating running couplings in asymptotic safety to assess singularity resolution in black holes, highlighting the role of the cosmological constant.

Findings

Antiscreening can remove singularities with a zero cosmological constant.

A nonzero ultraviolet cosmological constant tends to reintroduce singularities.

A finite infrared cosmological constant may be compatible with singularity resolution.

Abstract

We explore the fate of the curvature singularity of Schwarzschild (deSitter) black holes in asymptotically safe quantum gravity. Specifically, we upgrade the classical spacetime by including the running of the Newton coupling and cosmological constant. In this setting, the antiscreening character of the gravitational interaction can remove the singularity, yet a nonzero value of the cosmological constant in the ultraviolet appears to reintroduce it. We find hints that a finite value of the cosmological constant in the infrared is compatible with singularity resolution provided that the cosmological constant is driven to zero fast enough in the ultraviolet. We compare the corresponding bounds on the critical exponents to the literature.