The microcanonical treatment of black holes as opposed to the canonical formulation is reviewed and some major differences are displayed. We propose a microcanonical alternative to the thermodynamical expression for the number density and discuss its characteristics. In particular the decay rates are compared in the two different pictures and shown to predict significantly different fates for cosmological black holes.

• Received 12 December 1997

DOI:https://doi.org/10.1103/PhysRevD.58.044014