On Coherent Delocalization in the Light-Matter Interaction

TL;DR

This paper explores how the coherent delocalization of a particle's wave function influences its interaction with quantum fields, revealing phenomena like Cherenkov-like emissions during supersonic spreading.

Contribution

It introduces a generalized Unruh-deWitt model to analyze the effects of wave function delocalization on particle-field interactions, including novel emission phenomena.

Findings

Coherent spreading affects emission and absorption rates.

Supersonic spreading leads to Cherenkov-like emissions.

Wave function delocalization influences light-matter interaction dynamics.

Abstract

We investigate how the coherent spreading of the center of mass wave function of a particle, such as an atom, molecule or ion, affects the particle's interaction with fields such as the electromagnetic field or a phonon field, in view also of possible applications to emerging quantum technologies. To this end, we develop a suitably generalized Unruh-deWitt model for the interaction between a delocalizing first quantized particle and a second quantized field. We study how the coherent spreading of the center of mass wave function of the particle affects emission and absorption rates and we find, in particular, that in the case of a supersonic coherent spreading in a medium, there should occur Cherenkov-like emissions, along with the excitation of the particle.