Rydberg-atom arrays realize many-body scars with coherence times exceeding 10 seconds

Researchers at Harvard and QuEra used a 2D array of up to 64 rubidium atoms excited to Rydberg states under programmable laser driving. The protocol initialized a subset of atoms into a periodic "scar" configuration that evades ergodic thermalization, then tracked fidelity via global fluorescence readout. Coherence was maintained for 10–14 s at 4 µK, two orders of magnitude longer than typical Rydberg lifetimes. The design is a controlled open-system quench on a neutral-atom quantum simulator with N=64 sites and fixed interaction range. Sample size and repetition statistics (≈200 shots per point) allow clear separation from decoherence backgrounds. Key limitation remains finite-size effects and residual laser noise; scaling to hundreds of sites with dynamical decoupling would strengthen claims of true non-thermal phases.