Observation of Near-Critical Kibble-Zurek Scaling in Rydberg Atom Arrays

While finite-size effects and symmetry-breaking perturbations typically smear a critical point into a smooth crossover, we experimentally demonstrate that the precise Kibble-Zurek scaling can be retained in this near-critical crossover regime without strictly crossing the phase transition. The essential requirement is to appropriately scale both the system size and the symmetry-breaking field with the ramp speed. Using a reconfigurable Rydberg atom array—where the Rydberg blockade mediates a Z₂ symmetry-breaking transition—we achieve precise control over the system size and an effective symmetry-breaking field via a zigzag geometry. We show a notable contrast in the fidelity of Kibble-Zurek scaling when these parameters are or are not scaled correctly. Our findings reinforce the utility of Kibble-Zurek scaling as a robust tool for probing near-critical dynamics in quantum simulators.