Unruh's detector in the presence of Lorentz symmetry breaking
arXiv:0706.2767 · doi:10.1007/s10509-007-9554-0
Abstract
We investigate the quantum field theory of a Lorentz non-invariant model with a massive nonlinear dispersion relation in Minkowski space. The model involves some non-causal signals in the form of wave packets propagating with super-luminal group velocities. To avoid the problems with causality we characterize the causal sector of the theory by a cutoff condition excluding all super-luminal group velocities. It is argued that in the causal theory satisfying the energy positivity condition an Unruh's detector moving with a constant velocity with respect to the preferred frame does not detect any particle. But in a causal theory violating energy positivity, detection of a field quanta occurs. We comment on the origin of this particle creation.
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