Collective cluster nucleation dynamics in quantum magnets

Strongly interacting many-body systems exhibit collective properties that emerge from complex correlations among microscopic degrees of freedom. These cooperative phenomena govern the non-equilibrium response of quantum systems, with relevance ranging from condensed matter physics to quantum field theories describing fundamental aspects of our universe. Understanding such emergent dynamics from first principles remains one of the central challenges in quantum many-body physics. Here we report on the observation of collective cluster nucleation dynamics following quenches in 2D ferromagnetic quantum Ising systems implemented in an atomic Rydberg array. Our experiments reveal two distinct regimes: In the confined regime, we observe an energy-dependent cluster size, revealing large collective clusters exceeding ten spins. In contrast, the deconfined regime is characterized by kinetically constrained, avalanche-like nucleation dynamics involving the entire system. Our findings establish a new frontier for quantum simulations with Rydberg arrays, enabling controlled exploration of non-equilibrium phenomena previously out of reach. Beyond advancing experimental capabilities, they provide fundamental insights into highly correlated processes with implications that reach from quantum magnetism and glassy dynamics to cosmological models of the early universe.