Signature change in 2-dimensional black-hole models of loop quantum   gravity
  Signature change has been identified as a generic consequence of holonomy modifications in spherically symmetric models of loop quantum gravity with real connections, which includes modified Schwarzschild solutions. Here, this result is extended to 2-dimensional dilaton models and to different choices of canonical variables, including in particular the Callan-Giddings-Harvey-Strominger (CGHS) solution. New obstructions are found to coupling matter and to including operator-ordering effects in an anomaly-free manner. 
Martin Bojowald and Suddhasattwa Brahma
gr-qc hep-th