Second-quantized Unruh-DeWitt detectors and their quantum reference frame transformations

TL;DR

This paper extends the Unruh-DeWitt detector model to second quantization, analyzes decay in superpositions of velocities, and develops quantum reference frame transformations for such detectors, enabling analysis of superposed relativistic states.

Contribution

It introduces a second-quantized version of the Unruh-DeWitt detector and generalizes quantum reference frame transformations to these detectors, allowing analysis of superpositions of relativistic velocities.

Findings

Decay depends on coherence of velocity superpositions.

Framework enables transforming into rest frames of superposed states.

Application to a decaying particle in superposition of velocities.

Abstract

We generalize the Unruh-DeWitt detector model to second quantization. We illustrate this model by applying it to an excited particle in a superposition of relativistic velocities. We calculate, to first order, how its decay depends on whether its superposition of velocities is coherent or incoherent. Further, we generalize the framework of quantum reference frames to allow transformations to the rest frames of second-quantized Unruh DeWitt detectors. As an application, we show how to transform into the rest frame of a decaying particle that, in the laboratory frame, is in a linear superposition of relativistically differing velocities.