Quantization of the Reissner-Nordstr\"{o}m Black Hole
  The Reissner--Nordstr\"{o}m family of solutions can be understood to arise from the spherically symmetric sector of a nonlinear SO(2,1)/SO(1,1) sigma model coupled to three dimensional Euclidean gravity. In this context a group theoretical quantization is performed. We identify the observables of the theory and calculate their spectra. 
P. Breitenlohner (Munich, Max Planck Inst.), H. Hollmann (Cambridge,   DAMTP), D. Maison (Munich, Max Planck Inst.)