ENTROPY OF SEMICLASSICAL 2D DILATON BLACK HOLES AWAY FROM THE HAWKING TEMPERATURE

Abstract

Recently we showed that in semiclassical 2D dilaton gravity the regularity of a black hole horizon may be compatible with divergencies of Polyakov–Liouville stresses on it, the temperature deviating from its Hawking value. This makes the question about thermal properties of such solutions nontrivial. We demonstrate that, adding to gravitation–dilaton part of the action certain counterterms, which diverge on the horizon but are finite outside it, one may achieve finiteness of the effective gravitation–dilaton couplings on the horizon. This gives for the entropy S the Bekenstein–Hawking value in the nonextreme case and S = 0 in the extreme one similarly to what happens to "standard" black holes.