Black hole thermodynamics and two-dimensional dilaton gravity theory

We relate various black hole solutions in the near-horizon region to black hole solutions in two-dimensional dilaton gravity theories in order to argue that the thermodynamics of black holes in D greater than or equal to 4 can be effectively described by the thermodynamics of black holes in two-dimensional dilaton gravity theories. We show that the Bekenstein-Hawking entropies of single-charged dilatonic black holes and dilatonic p branes with an arbitrary dilaton coupling parameter in arbitrary spacetime dimensions are exactly reproduced by the Bekenstein-Hawking entropy of the two-dimensional black hole in the associated two-dimensional dilaton gravity model. We comment that the thermodynamics of a nonextreme stringy four-dimensional black hole with four charges and a five-dimensional black hole with three charges may be effectively described by the thermodynamics of black hole solutions with a constant dilaton field in two-dimensional dilaton gravity theories.