Uncoupled dark states can inherit polaritonic properties

TL;DR

This paper demonstrates theoretically that dark states in strongly coupled light-matter systems can inherit delocalized, polariton-like properties when the electromagnetic field has a discrete spectrum, enhancing excitation transfer efficiency.

Contribution

It reveals that dark states can exhibit delocalization and polaritonic characteristics without photonic components under specific conditions.

Findings

Dark states can be delocalized despite lacking photonic components.

Dark states can outperform polaritons in excitation transfer.

Discrete spectrum of the electromagnetic field is crucial for this behavior.

Abstract

When a collection of quantum emitters interacts with an electromagnetic field, the whole system can enter into the collective strong coupling regime in which hybrid light-matter states, i.e., polaritons can be created. Only a small portion of excitations in the emitters are coupled to the light field, and there are many dark states that, in principle, retain their pure excitonic nature. Here we theoretically demonstrate that these dark states can have a delocalized character, which is inherent to polaritons, despite the fact that they do not have a photonic component. This unexpected behavior only appears when the electromagnetic field displays a discrete spectrum. In this case, when the main loss mechanism in the hybrid system stems from the radiative losses of the light field, dark states are even more efficient than polaritons in transferring excitations across the structure.