Black Hole Entropy
arXiv:hep-th/9412211
Abstract
In the talk different definitions of the black hole entropy are discussed and compared. It is shown that the Bekenstein-Hawking entropy (defined by the response of the free energy of a system containing a black hole on the change of the temperature) differs from the statistical- mechanical entropy $S^{SM}=-\mbox{Tr}(\hatρ\ln \hatρ)$ (defined by counting internal degrees of freedom of a black hole). A simple explanation of the universality of the Bekenstein-Hawking entropy (i.e. its independence of the number and properties of the fields which might contribute to ) is given.
16 pages, LaTeX; Talk at the Winnipeg Heat Kernel Conference (Aug,94)