BMS Goldstone modes near the horizon of a Kerr black hole are thermal

TL;DR

This paper explores how Goldstone modes near the horizon of Kerr black holes exhibit thermal behavior similar to Hawking radiation, extending previous Schwarzschild results to rotating black holes and suggesting a role in horizon thermalization.

Contribution

It generalizes the analysis of Goldstone modes from Schwarzschild to Kerr black holes, including slowly rotating and zero angular momentum observer frames, revealing their thermal properties.

Findings

Goldstone modes near Kerr horizons are thermal and proportional to Hawking temperature.

The analysis applies to both slowly rotating and arbitrary rotation Kerr black holes.

Goldstone modes may be key to understanding microscopic horizon thermalization.

Abstract

Near horizon Bondi-Metzner-Sachs (BMS) like symmetry is spontaneously broken by the black hole background itself and hence gives rise to Goldstone mode. The associated Goldstone mode for the near horizon BMS like symmetry of a Schwarzschild black hole was found to behave like inverted harmonic oscillators, which has been further shown to lead to thermodynamic temperature in the semi-classical regime. Here we investigate the generalization of this previous findings for the Kerr black hole. The analysis is being performed for two different situations. Firstly, we analyze Goldstone mode dynamics considering {\it slowly rotating} Kerr. In other case the problem is solved in the frame of {\it zero angular momentum observer} (ZAMO) with arbitrary value of rotation. In both analysis the effective semi-classical temperature of Goldstone modes turn out to be proportional to that of Hawking temperature. Due to such similarity and generality we feel that these Goldstone modes may play important role to understand the underlying microscopic description of horizon thermalization.