Comment on "Black hole constraints on varying fundamental constants"

TL;DR

This paper critiques previous claims that black hole thermodynamics constrains the variation of fundamental constants, arguing that assumptions about black hole mass stability are flawed and no model-independent limits can be derived from entropy considerations.

Contribution

It challenges prior work by showing that black hole mass can vary with fundamental constants, invalidating previous thermodynamic constraints on their variation.

Findings

Black hole mass varies with fundamental constants during adiabatic processes

Previous assumptions of constant black hole mass are incorrect

No model-independent limits on fundamental constant variation from second law

Abstract

In the Letter [1] (also [2]) there is a claim that the generalised second law of thermodynamics (entropy increase) for black holes provides some limits on the rate of variation of the fundamental constants of nature (electric charge e, speed of light c, etc.). We have come to a different conclusion. The results in [1,2] are based on assumption that mass of a black hole does not change without radiation and accreation. We present arguments showing that this assumption is incorrect and give an estimate of the black hole mass variation due to alpha=e^2/\hbar c variation using entropy (and quantum energy level) conservation in an adiabatic process. No model-independent limits on the variation of the fundamental constants are derived from the second law of thermodynamics.