Projected equations of motion approach to hybrid quantum/classical dynamics in dielectric-metal composites

TL;DR

This paper presents a hybrid quantum/classical approach using projected equations of motion to model dielectric-metal composites, accurately capturing dynamics under ultrashort pulse excitation where traditional methods fail.

Contribution

The paper introduces the PEOM method for hybrid quantum/classical dynamics, effectively coupling quantum dielectrics with classical metals in composite systems.

Findings

PEOM method agrees with RWA in energy absorption calculations.

PEOM accurately models population inversion under ultrashort pulses.

Method outperforms traditional RWA in certain dynamic regimes.

Abstract

We introduce a hybrid method for dielectric-metal composites that describes the dynamics of the metallic system classically whilst retaining a quantum description of the dielectric. The time-dependent dipole moment of the classical system is mimicked by the introduction of projected equations of motion (PEOM) and the coupling between the two systems is achieved through an effective dipole-dipole interaction. To benchmark this method, we model a test system (semiconducting quantum dot-metal nanoparticle hybrid). We begin by examining the energy absorption rate, showing agreement between the PEOM method and the analytical rotating wave approximation (RWA) solution. We then investigate population inversion and show that the PEOM method provides an accurate model for the interaction under ultrashort pulse excitation where the traditional RWA breaks down.