Extremal isolated horizon/CFT correspondence

Abstract

The near-horizon limit of the extremal (weakly) isolated horizon is obtained under the Bondi-like coordinates. For the vacuum case, explicit coordinate transformation relating the near-horizon metric under the Bondi-like coordinates and the standard Poincar\'e-type or global near-horizon metric of the extremal Kerr black hole is found, which shows that the two geometries are the same. Combined with the known thermodynamics of the (weakly) isolated horizon, it is argued that the Kerr/conformal field theory correspondence can be generalized to the case of a large class of nonstationary extremal black holes.