Causal particle detectors and topology

We investigate particle detector responses in some topologically non-trivial spacetimes. We extend a recently proposed regularization of the massless scalar field Wightman function in four-dimensional Minkowski space to arbitrary dimension, to the massive scalar field, to quotients of Minkowski space under discrete isometry groups and to the massless Dirac field. We investigate in detail the transition rate of inertial and uniformly accelerated detectors on the quotient spaces under groups generated by (t, x, y, z) ↦ (t, x, y, z + 2a), (t, x, y, z) ↦ (t, −x, y, z), (t, x, y, z) ↦ (t, −x, −y, z), (t, x, y, z) ↦ (t, −x, −y, z + a) and some higher dimensional generalizations. For motions in at constant y and z   on the latter three spaces the response is time dependent. We also discuss the response of static detectors on the RP3RP3 geon and inertial detectors on RP3RP3 de Sitter space via their associated global embedding Minkowski spaces (GEMS). The response on RP3RP3 de Sitter space, found both directly and in its GEMS, provides support for the validity of applying the GEMS procedure to detector responses and to quotient spaces such as RP3RP3 de Sitter space and the RP3RP3 geon where the embedding spaces are Minkowski spaces with suitable identifications.