Integrable models and degenerate horizons in two-dimensional gravity - art. no. 024011

We analyze an integrable model of two-dimensional gravity which can be redu ced to a pair of Liouville fields in the conformal gauge. Its general solut ion represents a pair of "mirror" black holes with the same temperature. Th e ground state is a degenerate constant dilaton configuration similar to th e Nariai solution of the Schwarzschild-de Sitter case. The existence of phi = const solutions and their relation to the solution given by the 2D Birkho ff theorem is then investigated in a more general context. We also point ou t some interesting features of the semiclassical theory of our model and th e similarity with the behavior of AdS(2) black holes.