Hawking radiation for Dirac spinors on the RP geon

We analyse the Hawking-(Unruh) effect for a massive spinor field on the single exterior black hole spacetime known as the RP geon. This spacetime is an inextendible, space and time orientable black hole locally isometric to the Kruskal manifold but with only one exterior region. We find that the Hartle-Hawking-like vacuum |0G〉 contains exterior region Boulware modes in correlated pairs. Any operator in the exterior which couples to only one member of each pair has thermal expectation values at the usual temperature. However generic operators do not have this form, in contrast to the analogous situation on Kruskal. The choice of the spin structure enters the expression for |0G〉 in terms of the Boulware vacuum. Analogous results are found for the Unruh effect for acceleration horizons on a family of flat but topologically non-trivial spacetimes whose global properties mimic those of the Kruskal manifold and the RP geon. For neutrinos we present the energy-momentum tensor expectation value on these flat spacetimes in the Minkowski-like vacuum and discuss its dependence on the spin structure.