The Schwarzschild singularity: a semiclassical bounce?

TL;DR

This paper explores the possibility that the classical singularity inside a Schwarzschild black hole could be replaced by a quantum-induced bounce, modeled as a regular minimum of the radius, within a semiclassical framework involving vacuum polarization effects.

Contribution

It proposes a semiclassical model where quantum vacuum polarization causes a bounce replacing the singularity in Schwarzschild black holes, consistent with Einstein equations and curvature-quadratic effective action.

Findings

The model achieves a regular bounce at a scale near the GUT scale.

The solution remains within a semiclassical regime, away from Planck-scale physics.

Vacuum polarization effects can produce a non-singular black hole interior.

Abstract

We discuss the opportunity that the singularity inside a Schwarzschild black hole could be replaced by a regular bounce, described as a regular minimum of the spherical radius (instead of zero) and a regular maximum of the longitudinal scale (instead of infinity) in the corresponding Kantowski-Sachs metric. Such a metric in a vicinity of the bounce is shown to be a solution to the Einstein equations with the stress-energy tensor representing vacuum polarization of quantum matter fields, described by a combination of curvature-quadratic terms in the effective action. The indefinite parameters of the model can be chosen in such a way that it remains a few orders of magnitude apart from the Planck scale (say, on the GUT scale), that is, in a semiclassical regime.