Internal Quantum Dynamics of a Nanoparticle in a Thermal Electromagnetic Field: a Minimal Model

TL;DR

This paper introduces a minimal quantum model for describing the thermalization process of a levitated nanoparticle in a thermal electromagnetic field, surpassing traditional macroscopic electrodynamics and providing testable predictions.

Contribution

The authors develop an exact analytical quantum model for nanoparticle thermalization, extending beyond quasi-equilibrium assumptions and linking microscopic parameters to macroscopic responses.

Findings

Quantum model predicts different energy evolution than macroscopic electrodynamics.

Analytical solutions match known response functions.

Model provides experimentally testable predictions.

Abstract

We argue that macroscopic electrodynamics is unsuited to describe the process of radiative thermalization between a levitated nanoparticle in high vacuum and the thermal electromagnetic field. Based on physical arguments, we propose a model to describe such systems beyond the quasi-equilibrium approximation. We use path integral techniques to analytically solve the model and exactly calculate the time evolution of the quantum degrees of freedom of the system. Free parameters of the microscopic quantum model are determined by matching analytical results to well-known macroscopic response functions. The time evolution of the internal energy of a levitated nanoparticle in a thermal electromagnetic field, as described by our model, qualitatively differs from macroscopic electrodynamics, a prediction that can be experimentally tested.