Response of accelerated detectors in coherent states and the semi-classical limit

Abstract

It is known that a uniformly accelerating detector gets excited in the inertial vacuum of a field, as if it were immersed in a thermal bath. We study the effect that the choice of the quantum state has on the response of the detector. The ‘‘correlation function’’ 〈Ψ‖φ(x)φ(x’)‖Ψ〉 is computed in a Fock state, in the coherent state, and in the thermal state. It is then shown that the response function is a sum of two terms—the first being the same as the response in the vacuum state and a second term which is state dependent. The limit of the response function as ħ→0 is discussed and the response of the inertial and accelerated detectors compared in this limit. The response in the large-nk limit of the Fock state is compared with the response in the coherent state. We conclude that the thermal response of an accelerated detector in the inertial vacuum has interesting similarities to its response in other states.