In the framework of quantum field theory in curved space-time, we study the quantization of a massless fermion field on a non-extremal Kerr black hole. The key theme in this note is the fundamental difference between scalar and fermion fields for the process of defining quantum states. In particular, we define two new states for fermions on Kerr which cannot be defined for quantum scalar fields on Kerr. These two states are the analogues of the standard Boulware and Hartle-Hawking states on a Schwarzschild black hole.
This note discusses work completed in collaboration with Marc Casals, Sam Dolan, Brien Nolan and Adrian Ottewill. This work was supported by the Lancaster-Manchester-Sheffield Consortium for Fundamental Physics under STFC Grant No. ST/J000418/1, by an International Visitor Programme Grant from the Office of the Vice President for Research in Dublin City University and by EU COST Action MP0905 “Black Holes in a Violent Universe”. We thank Victor Ambrus for helpful discussions.