On AdS black holes in two-dimensional dilaton gravity

Abstract: In this paper, we present two novel analytic AdS black hole solutions in a two-dimensional dilaton gravity theory with two scalar fields non-minimally coupled to gravity. Our solutions contain two arbitrary integration constants in the blackening factor $f(r)$, allowing for an extremal configuration. Solution I reproduces a previously reported AdS black hole when one of the integration constants in $f(r)$ vanishes. For our black hole configurations, the scalar curvature is constant and negative, corresponding to the $AdS_2$ spacetime. In order to elucidate their black hole nature, we explore the causal structure of these solutions with the aid of suitable Kruskal-like coordinates and Penrose diagrams. By employing the Hamilton-Jacobi method, we construct a boundary counter-term that renders a renormalized action with a vanishing variation. We use this finite action for the partition function in the semi-classical approximation. We establish a consistent Thermodynamics, verified by the first law, for our black hole solutions, including the extremal case.