Quantum radiation by an Unruh-DeWitt detector in oscillatory motion

TL;DR

This paper investigates quantum radiation emitted by an oscillating Unruh-DeWitt detector in Minkowski space, revealing effects like negative power periods, high harmonic generation, and the influence of quantum interference.

Contribution

It provides a non-perturbative numerical analysis of quantum radiation from an oscillating detector, highlighting the role of acceleration, interference, and harmonic generation.

Findings

Pronounced Unruh-like effect in high acceleration regimes

Periods of negative radiated power observed at fixed angles

Identification of high harmonic generation and down conversion

Abstract

Quantum radiated power emitted by an Unruh-DeWitt (UD) detector in linear oscillatory motion in (3+1)D Minkowski space, with the internal harmonic oscillator minimally coupled to a massless scalar field, is obtained non-perturbatively by numerical method. The signal of the Unruh-like effect experienced by the detector is found to be pronounced in quantum radiation in the highly non-equilibrium regime with high averaged acceleration and short oscillatory cycle, and the signal would be greatly suppressed by quantum interference when the averaged proper acceleration is sufficiently low. An observer at a fixed angle would see periods of negative radiated power in each cycle of motion, while the averaged radiated power over a cycle is always positive as guaranteed by the quantum inequalities. Coherent high harmonic generation and down conversion are identified in the detector's quantum radiation. Due to the overwhelming largeness of the vacuum correlators of the free field, the asymptotic reduced state of the harmonics of the radiation field is approximately a direct product of the squeezed thermal states.