New Insights into Uniformly Accelerated Detector in a Quantum Field

TL;DR

This paper provides an exact solution for a uniformly accelerated detector in a quantum field, revealing limitations of the Unruh effect in certain regimes and identifying late-time quantum radiation in (3+1)D.

Contribution

It offers a novel exact solution for the detector-field system in (3+1)D, enabling comprehensive analysis of transient and steady states, and clarifies the validity limits of the Unruh effect.

Findings

Unruh effect validity is limited to transient stages.

Steady-state (3+1)D detector emits quantum radiation.

Unruh effect does not account for late-time quantum radiation.

Abstract

We obtained an exact solution for a uniformly accelerated Unruh-DeWitt detector interacting with a massless scalar field in (3+1) dimensions which enables us to study the entire evolution of the total system, from the initial transient to late-time steady state. We find that the Unruh effect as derived from time-dependent perturbation theory is valid only in the transient stage and is totally invalid for cases with proper acceleration smaller than the damping constant. We also found that, unlike in (1+1)D results, the (3+1)D uniformly accelerated Unruh-DeWitt detector in a steady state does emit a positive radiated power of quantum nature at late-times, but it is not connected to the thermal radiance experienced by the detector in the Unruh effect proper.