The conjectured equivalence, in the string theory approach to quantum gravity, between supergravity in D-dimensional anti-de Sitter space-time AdS(D) and some quantum conformal field theory living on its boundary has been viewed as evidence for the existence of a holographic principle in quantum physics, which was first inspired by black hole physics.
I will show that there are CLASSICAL degrees of freedom on the conformal boundary of AdS(D) which generate all AdS(D) Schwarzschild and Kerr black holes. Their classical effective boundary action is conformally invariant for odd dimensional space-time boundaries and presents a conformal anomaly for even ones. These degrees of freedom are encoded in traceless tensor fields which plays the role of their energy momentum tensor. In 2+1 dimensions, these tensor fields generate the Virasoro algebra with classical central charge and the local expression of the degrees of freedom is given by the Liouville field in a general curved background.
I shall comment on the significance of these results.