Are the black hole remnants produced from binary black hole mergers in GWTC-3 thermodynamically stable?

TL;DR

This study uses observational data from LIGO, Virgo, and KAGRA to verify that black hole remnants from binary mergers are thermodynamically stable, supporting the connection between gravity, thermodynamics, and quantum theory.

Contribution

First observational verification that black hole remnants from binary mergers are thermodynamically stable based on GWTC-3 data.

Findings

Remnant population is consistent with thermodynamic stability with 99.98% probability.

Black hole remnants satisfy the stability criterion related to their spin.

This is the first direct verification of thermodynamic stability of merger-produced black hole remnants.

Abstract

Black hole thermodynamics has brought strong hints of a profound and fundamental connection between gravity, thermodynamics, and quantum theory. If the black hole does behave like a natural thermodynamic system, it should be thermodynamically stable in a clean environment. In this paper, using the observational data of binary black hole (BBH) mergers observed by LIGO, Virgo, and KAGRA detectors, we check whether the black hole remnants produced from BBH mergers in the LIGO-Virgo-KAGRA catalog GWTC-3 are thermodynamically stable. The criterion for the thermodynamic stability is quite simple and is directly related to the black hole's spin, which states that a thermodynamically stable black hole remnant requires its dimensionless spin $a>a_* \simeq 0.68$. We check the posterior distributions of final spin $a_f$ for 83 black hole remnants in GWTC-3 and find the whole remnant population is consistent with the thermodynamically stable black hole with $99.98\%$ probability. This is the first verification of the thermodynamic stability of black hole remnants produced from BBH mergers.