Particle Detectors from Localized Quantum Field Theories

TL;DR

This paper develops a relativistic model for localized quantum field probes, deriving particle detector models from localized fields and showing their predictions align with traditional models at leading order.

Contribution

It introduces a fully relativistic localized quantum field model that reproduces particle detector behavior by tracing out inaccessible degrees of freedom.

Findings

Particle detector models can be derived from localized quantum fields.

Predictions of the new models match traditional detector models at leading order.

The approach provides a fully relativistic framework for localized probes in quantum field theory.

Abstract

We present a fully relativistic model for localized probes in quantum field theory. Furthermore, we show that it is possible to obtain particle detector models from localized quantum field theories that interact with a free quantum field. In particular, a particle detector model is obtained when one traces out over inaccessible degrees of freedom of the localized field. This gives rise to a particle detector model, that is, a quantum degree of freedom that couples to a free field theory in an extended region of spacetime. Moreover, we show that the predictions of traditional particle detector models and fully relativistic localized fields completely coincide to leading order in perturbation theory.