Phase diagram of a QED-cavity array coupled via a N-type level scheme

TL;DR

This paper explores the complex phase diagram of a one-dimensional QED cavity array with N-type level coupling, revealing various quantum phases using advanced numerical methods.

Contribution

It introduces a novel model of QED cavities with N-type coupling and maps out its rich quantum phase diagram using density-matrix renormalization group techniques.

Findings

Identification of polaritonic Mott insulator, density-wave, and superfluid phases.

Phase boundaries determined by energy gap analysis and correlation functions.

Demonstration of tunable quantum phases via coupling strength variations.

Abstract

We study the zero-temperature phase diagram of a one-dimensional array of QED cavities where, besides the single-photon hopping, an additional coupling between neighboring cavities is mediated by an N-type four-level system. By varying the relative strength of the various couplings, the array is shown to exhibit a variety of quantum phases including a polaritonic Mott insulator, a density-wave and a superfluid phase. Our results have been obtained by means of numerical density-matrix renormalization group calculations. The phase diagram was obtained by analyzing the energy gaps for the polaritons, as well as through a study of two-point correlation functions.