Black hole spectroscopy via adiabatic invariance

TL;DR

This paper derives an equally spaced black hole entropy spectrum using adiabatic invariance of the horizon area, avoiding the need for quasinormal mode concepts, and aligns with Bekenstein's quantum.

Contribution

It introduces a method to obtain black hole entropy quantization solely based on adiabatic invariance, bypassing quasinormal mode analysis.

Findings

Derived an equally spaced entropy spectrum for black holes.

Confirmed the quantum of entropy matches Bekenstein's prediction.

Showed that quasinormal modes are not necessary for entropy quantization.

Abstract

During the last years, one had to combine the proposal about how quasinormal frequencies are related with black holes and the proposal about the adiabatic invariance of black holes in order to derive the quantized entropy spectrum and its minimum change for several black holes. In this letter we exclusively utilize the statement that the black hole horizon area is an adiabatic invariant and derive an equally spaced entropy spectrum of a black hole with its quantum to be equal to the one given by Bekenstein. Interestingly, in our approach no concept of quasi-normal mode is needed.