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

Understand

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.