A four-dimensional dilaton-gravity action whose spherical reduction to two dimensions leads to the Jackiw-Teitelboim theory is presented. A nonsingular black hole solution of the theory is obtained and its physical interpretation is discussed. The classical and semiclassical properties of the solution and of its two-dimensional counterpart are analyzed. The two-dimensional theory is also used to model the evaporation process of the near-extremal four-dimensional black hole. We describe in detail the peculiarities of the black hole solutions, in particular, the purely topological nature of the Hawking radiation, in the context of the Jackiw-Teitelboim theory.

• Received 7 October 1994

DOI:https://doi.org/10.1103/PhysRevD.51.4319