Field assisted extraction and swelling of quantum coherence for moving Unruh-DeWitt detectors

Abstract

We study the effects of motion for an Unruh-DeWitt detector, modeled as a two-level system, on the amount of coherence extracted, when it interacts with a massless scalar coherent field in 1+1 Minkowski spacetime. We observe that compared to a detector at rest, for certain values of the initial energy of the field and the interaction duration, the amount is larger for both a detector moving with a constant speed or uniform acceleration. This "swelling" of coherence, which becomes more intense for increasing values of velocity or acceleration, is mostly observed for short durations, when the energy of the field is larger compared to that of the detector, and for longer durations but smaller field energies. As a consequence, the rate at which coherence is lost, is sometimes slower for a moving detector than for a detector at rest.