Quantum phase transitions in photonic cavities with two-level systems

TL;DR

This paper investigates quantum phase transitions in small networks of coupled photonic cavities with two-level systems, analyzing phase diagrams, effects of temperature, and disorder, revealing shrinking Mott lobes similar to the Bose-Hubbard model.

Contribution

It provides a detailed analysis of quantum phase transitions in finite photonic cavity systems, including phase diagrams and effects of temperature and disorder, extending the understanding beyond mean-field approximations.

Findings

Mott lobes shrink with finite temperature and disorder

Quantum phase diagrams are consistent with the Bose-Hubbard model

Finite systems exhibit clear signatures of quantum phase transitions

Abstract

Systems of coupled photonic cavities have been predicted to exhibit quantum phase transitions by analogy with the Hubbard model. To this end, we have studied topologies of few (up to six) photonic cavities each containing a single two-level system. Quantum phase space diagrams are produced for these systems, and compared to mean-field results. We also consider finite effective temperature, and compare this to the notion of disorder. We find the extent of the Mott lobes shrink analogously to the conventional Bose-Hubbard model.