Quantum plasmonics with N emitters: bright hybrid continuum selection

TL;DR

This paper develops effective models for quantum plasmon-polariton interactions with multiple emitters, simplifying complex continuum spectra into manageable hybrid models that align with existing Langevin approaches.

Contribution

It introduces a mode-selective effective modeling approach that reduces the continuum spectrum to a smaller set of non-degenerate continua for multiple emitters.

Findings

The quantum plasmon-polariton field can be represented by a double or single hybrid continuum spectrum.

The effective interaction involves N non-degenerate one-dimensional continua for N emitters.

The hybrid continuum spectrum representation matches the macroscopic Langevin model results.

Abstract

We construct mode-selective effective models describing the interaction of the quantum plasmon-polariton field supported by a finite dielectric medium and one or several quantum emitters. The construction of the effective model is based on the decomposition of the field into bright modes relevant to the interaction with the emitters and dark modes, which do not interact with the emitters. We show that the quantum plasmon-polariton field can be represented equivalently by a double-continuum spectrum or by a single hybrid continuum spectrum for each emitter. The system of the electromagnetic field coupled to a finite medium is composed of two families of continuum modes, each of them with an infinite degeneracy. The two families are deformations of the free electromagnetic field and the free medium, induced by the interaction between them, as described by the Lippmann-Schwinger equations. We show that if there are $N$ emitters interacting with this plasmon-polariton field, the effective interaction involves a much smaller set of bosonic continuum modes: the interacting part of the continuum can be described by $N$ non-degenerate one-dimensional continua, one for each emitter. The representation of the interaction in terms of a single hybrid continuum spectrum coincides with the one within the macroscopic Langevin model with bulk medium. This coincidence is explained by an exact compensation of two terms, one in the coupling term of the Hamiltonian and the other one in a Green tensor identity.