Entropy of 2D black holes from counting microstates

We present a microscopical derivation of the entropy of the black hole solutions of the Jackiw-Teitelboim theory. We show that the asymptotic symmetry of two-dimensional (2D) anti–de Sitter space is generated by a central extension of the Virasoro algebra. Using a canonical realization of this symmetry and Cardy’s formula we calculate the statistical entropy of 2D black holes, which turns out to agree, up to a factor $\sqrt{2}$, with the thermodynamical result.