Abstract. In this talk, expanding upon [arXiv:1404.4472, 1511.06079], we provide further detailed analysis of Banados geometries, the most general solutions to the AdS3 gravity with Brown-Henneaux boundary conditions. We analyze in some detail the causal, horizon and boundary structure, and geodesic motion on these geometries. We elaborate further and establish the one-to-one relation between representations of two copies of Virasoro group and Banados geometries. Virasoro group representations fall into the Virasoro coadjoint orbits where each orbit is labelled by at most two quantum numbers (an integer and a continuous parameter) and states in a given orbit are specified by their charges under Virasoro generators L_n's. We show that local (classical) gravity probes can only measure orbit invariant quantities. Details of the Virasoro charges associated with each geometry is only available to semiclassical or non-local observables. In particular, we also elaborate on multi-BTZ geometries which have some number of disconnected pieces at the horizon bifurcation curve. We study multi-BTZ black hole thermodynamics and discuss that the thermodynamic quantities are orbit invariants. Our analysis sheds further light on the picture that a (multi-)BTZ black hole at the classical gravity level is specified by orbit invariant quantities (mass, angular momentum, and number of pieces at the horizon and boundary), while black hole microstates may be identified with Virasoro charges within a given orbit. We also discuss implications of our analysis for a 2d CFT dual which could possibly be dual to AdS3 Einstein gravity.
ICTP - Strada Costiera, 11
I - 34151 Trieste Italy (+39) 040 2240 111 email@example.com