Detector's response to coherent Rindler and Minkowski photons

TL;DR

This work probes whether the equivalence between Minkowski and Rindler descriptions persists when a detector couples to coherent photon states rather than vacua. By modeling a two-level Unruh-DeWitt detector interacting with a single-mode massless scalar field in coherent states, and by including boundary mirrors, the transition probabilities separate into vacuum and classical (P_α) contributions. In both (1+1)D and (3+1)D, P_α breaks the vacuum-derived symmetry under swapping detector and field frequencies, with the classical-field limit leaving only P_α; in 1+1D a joint classical-field-and-detector limit can restore symmetry, whereas in 3+1D this restoration is not evident within the studied regime. These results illuminate how classicality and frame choice shape non-inertial quantum responses and have implications for the interpretation of Unruh/Hawking effects and the quantum equivalence principle near horizons.

Abstract

We observe that the transition probability in a static two-level quantum detector interacting with a coherent Rindler photon is different from the same of the Rindler detector which is in interaction with a coherent Minkowski photon. Situation does not change in the response of quantum detector for the classical limit of the photon state. This we investigate in $(1+1)$ and $(3+1)$-spacetime dimensions. Interestingly, the transition probabilities of the ``classical'' detector in the classical limit of the photon state in $(1+1)$-dimensions, for these two scenarios, appear to be identical when the frequencies of photon mode and detector are taken to be same. However, our obtained detector's transition probabilities in $(3+1)$-dimensions, which are calculated under the large acceleration condition, do not show such signature. The implications of these observations are discussed as well.

Figures (1)

• Figure 1: $Y= \sin^2y/y$ vs $y=(\Delta E z_0)/\hbar$ graph.