QUANTUM GEOMETRY AND BLACK-HOLE ENTROPY

A ''black hole sector'' of nonperturbative canonical quantum gravity i s introduced. The quantum black hole degrees of freedom are shown to b e described by a Chern-Simons field theory on the horizon. It is shown that the entropy of a large nonrotating black hole is proportional to its horizon area. The constant of proportionality depends upon the Im mirzi parameter, which fixes the spectrum of the area operator in loop quantum gravity. an appropriate choice of this parameter gives the Be kenstein-Hawking formula S = A/4l(P)(2). With the same choice of the I mmirzi parameter, this result also holds or black holes carrying elect ric or dilatonic charge, which are not necessarily near extremal. [S00 31-9007(97)05183-1].