Ehrenfest Modeling of Cavity Vacuum Fluctuations and How to Achieve Emission from a Three-Level Atom

TL;DR

This paper introduces a generalized decoupled mean-field approach for modeling strong matter-cavity interactions, resolving unphysical predictions and improving the description of emission processes in multi-level atoms.

Contribution

It extends the decoupled mean-field dynamics to arbitrary atomic levels, addressing unphysical emission predictions and enhancing modeling accuracy.

Findings

Resolves unphysical lack of emission in three-level atoms.

Improves modeling of reabsorption and two-photon emission.

Generalizes DC-MF dynamics for multiple atomic levels.

Abstract

A much-needed solution for the efficient modeling of strong coupling between matter and optical cavity modes is offered by mean-field mixed quantum--classical dynamics, where a classical cavity field interacts self-consistently with quantum states of matter through Ehrenfest's theorem. We previously introduced a modified mean-field approach, referred to as decoupled mean-field (DC-MF) dynamics, wherein vacuum fluctuations of the cavity field are decoupled from the quantum-mechanical ground state as a means to resolve an unphysical drawing of energy from the vacuum fluctuations by a two-level atom. Here, we generalize DC-MF dynamics for an arbitrary number of (nondegenerate) atomic levels, and show that it resolves an unphysical lack of emission from a three-level atom predicted by conventional mean-field dynamics. We furthermore show DC-MF to provide an improved description of reabsorption and (resonant) two-photon emission processes.