Quantum phase transition of the two-dimensional Rydberg atom array in an optical cavity

TL;DR

This paper investigates the rich quantum phase diagram of a two-dimensional Rydberg atom array in an optical cavity, revealing multiple phases including superradiant solid, with findings supported by mean-field and quantum Monte Carlo methods.

Contribution

It introduces a comprehensive analysis of the 2D Rydberg atom array in an optical cavity, highlighting the emergence of a large superradiant solid phase and its experimental observability.

Findings

Superradiant solid phase is larger in 2D than in 1D.

Multiple quantum phases including Mott, solid-1/2, superradiant, and superradiant solid identified.

Energy gap influences the nature of quantum phase transitions and triple points.

Abstract

We study the two-dimensional Rydberg atom array in an optical cavity with help of the meanfield theory and the large-scale quantum Monte Carlo simulations. The strong dipole-dipole interactions between Rydberg atoms can make the system exhibit the crystal structure, and the coupling between two-level atom and cavity photon mode can result in the formation of the polariton. The interplay between them provides a rich quantum phase diagram including the Mott, solid-1/2, superradiant and superradiant solid phases. As the two-order co-existed phase, the superradiant solid phase breaks both translational and U(1) symmetries. Based on both numerical and analytic results, we found the region of superradiant solid is much larger than one dimensional case, so that it can be more easily observed in the experiment. Finally, we discuss how the energy gap of the Rydberg atom can affect the type of the quantum phase transition and the number of triple points.