Mass Inflation in the Loop Black Hole

TL;DR

This paper investigates mass inflation in loop quantum gravity black holes, showing that their Cauchy horizons develop curvature singularities similar to classical black holes, despite quantum corrections that remove the central singularity.

Contribution

It demonstrates that loop quantum gravity black holes still experience mass inflation at the Cauchy horizon, using simplified models and the DTR relation, highlighting the persistence of singularities.

Findings

Cauchy horizon leads to curvature singularity in loop black holes.

Mass inflation occurs despite quantum corrections removing the classical singularity.

The DTR relation is effective without relying on Einstein's equations.

Abstract

In classical general relativity the Cauchy horizon within a two-horizon black hole is unstable via a phenomenon known as mass inflation, in which the mass parameter (and the spacetime curvature) of the black hole diverges at the Cauchy horizon. Here we study this effect for loop black holes -- quantum gravitationally corrected black holes from loop quantum gravity -- whose construction alleviates the $r=0$ singularity present in their classical counterparts. We use a simplified model of mass inflation, which makes use of the generalized DTR relation, to conclude that the Cauchy horizon of loop black holes indeed results in a curvature singularity similar to that found in classical black holes. The DTR relation is of particular utility in the loop black hole because it does not directly rely upon Einstein's field equations. We elucidate some of the interesting and counterintuitive properties of the loop black hole, and corroborate our results using an alternate model of mass inflation due to Ori.