Microscopics of Rotating Black Holes: Entropy and Greybody Factors

Abstract

We review the status of microscopic counting of rotating black hole degrees of freedom. We present two complementary approaches which both utilize the near-horizon geometry and precisely reproduce the Bekenstein Hawking entropy for near-extreme rotating black holes in D=4 and D=5. The first one, proposed by Strominger, is applicable for the Ramond-Ramond sector and relies on the correspondence between the near-horizon geometry and the conformal field theory on its boundary. The second one (somewhat more heuristic), employs the conformal sigma-model in the Neveu-Schwarz-Neveu-Schwarz sector and accounts for the black hole microstates by counting the small scale oscillations of the dyonic string there. We also present the wave equation for the minimally coupled scalars for such rotating black hole background, and discuss its implication for the greybody factors. The results are illustrated for the prototype D=5 rotating black hole.