NEAR-HORIZON GEOMETRY AND BLACK-HOLES IN 4 DIMENSIONS

A large class of extremal and near-extremal four-dimensional black hol es in M-theory feature near-horizon geometries that contain three-dime nsional asymptotically anti-de Sitter spaces. Globally, these geometri es are derived from AdS(3) by discrete identifications. The microstate s of such black holes can be counted by exploiting the conformal symme try induced on the anti-de Sitter boundary, and the result agrees with the Bekenstein-Hawking area law. This approach, pioneered by Stroming er, clarifies the physical nature of the black hole microstates. It al so suggests that recent analyses of the relationship between boundary conformal field theory and supergravity can be extended to orbifolds o f AdS spaces. (C) 1998 Elsevier Science B.V.