Polaritonic characteristics of insulator and superfluid phases in a coupled-cavity array

TL;DR

This paper investigates the unique polaritonic properties of insulator and superfluid phases in a coupled-cavity array, highlighting differences from traditional Bose-Hubbard models through a detailed two-site analysis.

Contribution

It introduces a classification of ground states in a coupled-cavity system into four distinct phases, emphasizing the bipartite nature's effects.

Findings

Identification of four distinct phases: polaritonic insulator, photonic superfluid, atomic insulator, polaritonic superfluid.

Demonstration of the bipartite nature leading to unique phase behaviors.

Analysis over a wide parameter range reveals the conditions for each phase.

Abstract

Recent studies of quantum phase transitions in coupled atom-cavity arrays have focused on the similarities between such systems and the Bose-Hubbard model. However, the bipartite nature of the atom-cavity systems that make up the array introduces some differences. In order to examine the unique features of the coupled-cavity system, the behavior of a simple two-site model is studied over a wide range of parameters. Four regions are identified, in which the ground state of the system may be classified as either a polaritonic insulator, a photonic superfluid, an atomic insulator, or a polaritonic superfluid.