The Evolution of $\Lambda$ Black Holes in the Mini-Superspace Approximation of Loop Quantum Gravity

TL;DR

This paper investigates how loop quantum gravity modifies black hole evolution with a cosmological constant, showing singularities are replaced by bounces and the universe tends toward Nariai-type states, with unique behavior for planar black holes.

Contribution

It introduces an improved quantization method for mini-superspace loop quantum gravity and analyzes the quantum evolution of various black hole topologies with a cosmological constant.

Findings

Singularities are replaced by bounces in all studied scenarios.

Most evolutions asymptote to Nariai-type universes after the bounce.

Planar black holes exhibit different long-term expansion behavior.

Abstract

Using the improved quantization technique to the mini-superspace approximation of loop quantum gravity, we study the evolution of black holes supported by a cosmological constant. The addition of a cosmological constant allows for classical solutions with planar, cylindrical, toroidal and higher genus black holes. Here we study the quantum analog of these space-times. In all scenarios studied, the singularity present in the classical counter-part is avoided in the quantized version and is replaced by a bounce, and in the late evolution, a series of less severe bounces. Interestingly, although there are differences during the evolution between the various symmetries and topologies, the evolution on the other side of the bounce asymptotes to space-times of Nariai-type, with the exception of the planar black hole analyzed here, whose $T$-$R$=constant subspaces seem to continue expanding in the long term evolution. For the other cases, Nariai-type universes are attractors in the quantum evolution, albeit with different parameters. We study here the quantum evolution of each symmetry in detail.