Nonextremal Kerr/CFT on a stretched horizon

TL;DR

This paper investigates the conformal symmetry of nonextremal Kerr black holes on a stretched horizon, calculating central charges and reproducing entropy via the Cardy formula, extending Kerr/CFT correspondence beyond extremal cases.

Contribution

It introduces a method to derive conformal symmetry and central charges for nonextremal Kerr black holes using Hamiltonian gravity on a stretched horizon, providing a new extension of Kerr/CFT correspondence.

Findings

Calculated separate central charges for nonextremal Kerr black holes.

Reproduced Bekenstein-Hawking entropy using the Cardy formula.

Demonstrated conformal symmetry in nonextremal Kerr spacetime.

Abstract

We study the conformal symmetry described by $SL(2,R)_L \times SL(2,R)_R$ in the nonextremal Kerr black hole case. We calculate the central charges $c_{L,R}$ separately on a stretched horizon by the Hamiltonian gravity. In order to get two sets of conformal symmetry, we consider two Killing vectors each of which depends on either one of the two independent coordinates separated in the spirit of point-splitting from the angular coordinate of the corotating frame at the horizon. Then, we obtain the Bekenstein-Hawking entropy by the Cardy formula.