Effect of a moving mirror on the free fall of a quantum particle in a homogeneous gravitational field

TL;DR

This paper explores how a moving mirror affects the quantum behavior of a particle in free fall under gravity, revealing both classical-like and uniquely quantum effects, with implications for experiments using cold neutrons.

Contribution

It introduces a detailed analysis of the quantum bouncer with a moving boundary, highlighting novel quantum effects on wavefunction properties and potential experimental observations.

Findings

Moving mirrors can cause particles to bounce higher than fixed mirrors.

Quantum phases and current densities are altered far from the mirror.

Effects are observable with current cold neutron experiments.

Abstract

We investigate the effect of time-dependent boundary conditions on the dynamics of a quantum bouncer -- a particle falling in a homogeneous gravitational field on a moving mirror. We examine more particularly the way a moving mirror modifies the properties of the entire wavefunction of a falling particle. We find that some effects, such as the fact that a quantum particle hitting a moving mirror may bounce significantly higher than when the mirror is fixed, are in line with classical intuition. Other effects, such as the change in relative phases or in the current density in spatial regions arbitrarily far from the mirror are specifically quantum. We further discuss how the effects produced by a moving mirror could be observed in link with current experiments, in particular with cold neutrons.