Entropy from conformal field theory at Killing horizons

Abstract

On a manifold with boundary, the constraint algebra of general relativity may\nacquire a central extension, which can be computed using covariant phase space\ntechniques. When the boundary is a (local) Killing horizon, a natural set of\nboundary conditions leads to a Virasoro subalgebra with a calculable central\ncharge. Conformal field theory methods may then be used to determine the\ndensity of states at the boundary. I consider a number of cases---black holes,\nRindler space, de Sitter space, Taub-NUT and Taub-Bolt spaces, and dilaton\ngravity---and show that the resulting density of states yields the expected\nBekenstein-Hawking entropy. The statistical mechanics of black hole entropy may\nthus be fixed by symmetry arguments, independent of details of quantum gravity.\n