Thermodynamics of black holes with gauge cosmic strings and global monopoles Original Research Article

We show that the tree-level entropy of a black hole is unchanged when hair in the form of a gauge cosmic string or a global monopole appear on the black hole. When one-loop effects are taken into account the entropy of the black hole seems to increase in such a process. This treatment indicates that the origin of the tree-level entropy of a black hole is of a fundamentally different kind than the statistical mechanical nature of the higher-order contributions to the black hole entropy.