Holography, degenerate horizons and entropy

We show that a realization of the correspondence AdS(2)/CFT1 for near extre mal Reissner-Nordstrom black holes in arbitrary dimensional Einstein-Maxwel l gravity exactly reproduces, via Cardy's formula, the deviation of the Bek enstein-Hawking entropy from extremality. We also show that this mechanism is valid for Schwarzschild-de Sitter black holes around the degenerate solu tion dS(2) x S-n. These results reinforce the idea that the Bekenstein-Hawk ing entropy can be derived from symmetry principles. (C) 2000 Elsevier Scie nce B.V. All rights reserved.