On the physical meaning of the Unruh effect

TL;DR

This paper argues that uniformly accelerated detectors, including circular motion, detect particles due to a universal effect, and links the Unruh effect to the experimentally confirmed Sokolov--Ternov effect.

Contribution

It provides simple, universal arguments for particle detection by accelerated detectors and connects the Unruh effect with the Sokolov--Ternov effect through a physical analogy.

Findings

Uniform acceleration and circular motion detectors detect particles.

The Unruh effect is physically equivalent to the Sokolov--Ternov effect.

The effect is universal across different types of acceleration.

Abstract

We present simple arguments that detectors moving with constant acceleration (even acceleration for a finite time) should detect particles. The effect is seen to be universal. Moreover, detectors undergoing linear acceleration and uniform, circular motion both detect particles for the same physical reason. We show that if one uses a circularly orbiting electron in a constant external magnetic field as the Unruh--DeWitt detector, then the Unruh effect physically coincides with the experimentally verified Sokolov--Ternov effect.