Quantum criticality and nonequilibrium dynamics on a Lieb lattice of Rydberg atoms

TL;DR

This paper explores the rich quantum phases and dynamics of Rydberg atoms on a Lieb lattice, demonstrating experimental and theoretical insights into phase transitions, metastability, and slow relaxation in many-body quantum systems.

Contribution

It introduces a comprehensive study combining experiments, simulations, and analytics to reveal complex quantum phenomena on a Lieb lattice of Rydberg atoms, including novel phases and dynamics.

Findings

Identified density-wave-ordered phases including a quantum-fluctuation-stabilized collinear phase.

Discovered a quantum liquid-vapor transition with hysteresis between density-wave phases.

Observed slow relaxation dynamics consistent with emergent string phase constraints.

Abstract

Neutral-atom quantum simulators offer a promising approach to the exploration of strongly interacting many-body systems, with applications spanning condensed matter, statistical mechanics, and high-energy physics. Through a combination of quantum experiments, numerical calculations, and analytical methods, we demonstrate a rich set of phenomena accessible on such quantum simulators by studying an array of Rydberg atoms placed on the Lieb lattice. First, we map out the ground states and phase diagram of the system, identifying a range of density-wave-ordered phases -- including a collinear phase stabilized purely by quantum fluctuations -- and find good agreement between theory and experiment. Allowing for local control of the detuning field thereafter, we discover a quantum analog of the classical liquid-vapor transition between two density-wave phases distinguished by sublattice occupation, and probe its underlying hysteretic dynamics. Furthermore, we study out-of-equilibrium quantum quenches and observe anomalously slow relaxation dynamics consistent with the kinetic constraints of an emergent string phase. These results highlight how geometric control offered by neutral-atom simulators can extend the frontiers of programmable quantum matter, enabling access to complex phases, metastability, and thermalization dynamics in many-body quantum systems.