Complex density wave orders and quantum phase transitions in a model of square-lattice Rydberg atom arrays

TL;DR

This paper maps out the complex phase diagram of a 2D Rydberg atom array, revealing classical and quantum-ordered phases and novel quantum phase transitions, demonstrating the potential of Rydberg systems for exploring exotic many-body physics.

Contribution

It provides the first detailed phase diagram of a 2D Rydberg atom array, identifying quantum-ordered phases stabilized by quantum fluctuations and analyzing associated phase transitions.

Findings

Rich variety of density wave phases identified

Quantum fluctuations stabilize new ordered phases

Novel quantum phase transitions characterized

Abstract

We describe the zero-temperature phase diagram of a model of a two-dimensional square-lattice array of neutral atoms, excited into Rydberg states and interacting via strong van der Waals interactions. Using the density-matrix renormalization group algorithm, we map out the phase diagram and obtain a rich variety of phases featuring complex density wave orderings, upon varying lattice spacing and laser detuning. While some of these phases result from the classical optimization of the van der Waals energy, we also find intrinsically quantum-ordered phases stabilized by quantum fluctuations. These phases are surrounded by novel quantum phase transitions, which we analyze by finite-size scaling numerics and Landau theories. Our work highlights Rydberg quantum simulators in higher dimensions as promising platforms to realize exotic many-body phenomena.