Quantum symmetry breaking of exciton/polaritons in metal-nanorod plasmonic array

TL;DR

This paper investigates quantum phase transitions and Bose condensation of exciton-polaritons in a plasmonic nanorod array, revealing controllable superradiant behavior and collective quantum phenomena in a 1D system.

Contribution

It introduces a semi-empirical Hamiltonian for emitter-dressed nanorods and demonstrates conditions for polariton quantum phase transition and Bose condensation at finite temperatures.

Findings

Polariton states can undergo a quantum phase transition.

Bose condensate formation is possible at finite temperatures.

System parameters can be manipulated to control superradiant behavior.

Abstract

We study the collective, superradiant behavior in the system of emitter-dressed Ag nanorods. Starting from the Drude model for the plasmon oscillations, we arrive at a semi-empirical Hamiltonian describing the coupling between quantized surface plasmon modes and the quantum emitters that can be controlled by manipulating their geometry, spacing, and orientation. Further, identifying the lowest polariton mode as SP-states dressed by excitons in the vicinity of $k=0$, we examine conditions allowing for the polariton quantum phase transition. While the system is formally a 1D array, we show that the polariton states of interest can undergo a quantum phase transition to form a Bose condensate at finite temperatures for physically accessible parameter ranges.