Quantized scalar field in the stationary coordinate systems of flat spacetime

Abstract

A canonical quantization of the free scalar field is presented for the six classes of stationary coordinate systems in Minkowski space. The corresponding vacuum states are found to be restricted to two possibilities: Those in coordinate systems without event horizons are the Minkowski vacuum; those in coordinate systems with event horizons are the Fulling vacuum. The vacuum state is not in general the lowest energy state, but is stable due to the presence of additional symmetries, and a particle interpretation remains valid. These vacuum states are not compatible with vacuums defined by means of observer-based detectors.