Semiclassical Black Hole States and Entropy

We discuss semiclassical states in quantum gravity corresponding to Schwarzschild as well as Reissner Nordström black holes. We show that reduced quantisation of these models is equivalent to Wheeler-DeWitt quantisation with a particular factor ordering. We demonstrate how the entropy of black holes can be consistently calculated from these states. While this leads to the Bekenstein-Hawking entropy in the Schwarzschild and non-extreme Reissner-Nordström cases, the entropy for the extreme Reissner-Nordström case turns out to be zero