Is BTZ a separate superselection sector of CTMG?

TL;DR

This paper investigates the nature of BTZ black holes within cosmological TMG, providing evidence that they form a separate superselection sector and justifying the retention of TMG's original G-sign for stability.

Contribution

It demonstrates that BTZ solutions are a distinct superselection sector in cosmological TMG, not reachable from physical matter-coupled solutions, and supports the original G-sign choice for stability.

Findings

BTZ solutions evolve to conical singularities or negative mass.

BTZ constitutes a separate superselection sector in TMG.

Retaining the original G-sign ensures excitation stability.

Abstract

We exhibit exact solutions of (positive) matter coupled to cosmological TMG; they necessarily evolve to conical singularity/negative mass, rather than physical black hole, BTZ. By providing evidence that the latter constitutes a separate, "superselection", sector not reachable from the physical one, they also provide justification for retaining TMG's original "wrong" G-sign to ensure excitation stability here as well.