Subvacuum effects of the quantum field on the dynamics of a test particle

TL;DR

This paper investigates how electromagnetic subvacuum fluctuations can reduce the velocity uncertainty of a charged particle in a wavepacket, revealing conditions under which this quantum effect is significant or suppressed.

Contribution

It provides a detailed analysis of subvacuum effects on particle dynamics, including the impact of switching functions and non-inertial motion, advancing understanding of quantum noise manipulation.

Findings

Velocity dispersion is reduced in squeezed vacuum backgrounds.

Slow switching diminishes the subvacuum effect.

Non-inertial motion lessens the reduction in velocity uncertainty.

Abstract

We study the effects of the electromagnetic subvacuum fluctuations on the dynamics of a nonrelativistic charged particle in a wavepacket. The influence from the quantum field is expected to give an additional effect to the velocity uncertainty of the particle. In the case of a static wavepacket, the observed velocity dispersion is smaller in the electromagnetic squeezed vacuum background than in the normal vacuum background. This leads to the subvacuum effect. The extent of reduction in velocity dispersion associated with this subvacuum effect is further studied by introducing a switching function. It is shown that the slow switching process may make this subvacuum effect insignificant. We also point out that when the center of the wavepacket undergoes non-inertial motion, reduction in the velocity dispersion becomes less effective with its evolution, no matter how we manipulate the nonstationary quantum noise via the choice of the squeeze parameters. The role of the underlying fluctuation-dissipation relation is discussed.