Microcanonical quantum cosmology: gauge fixing and functional   determinants on a circle
  Gauge fixing procedure in the path integral for the microcanonical statistical sum in quantum cosmology is considered in a special class of gauge conditions free from residual gauge ambiguities. Relevant functional determinants, path integrals and functional delta-functions on a circle are considered. 
Dmitry Nesterov and Andrei Barvinsky
hep-th