Nonperturbative string dynamics in a (2+1)D lattice gauge theory on a superconducting quantum processor

Electric flux strings underpin confinement in gauge theories. In two spatial dimensions, their evolution involves competing processes of charge motion, pair creation, and transverse deformation. Accessing these dynamics beyond perturbative limits challenges classical approaches, as entanglement growth restricts the times accessible to tensor-network simulations. Here we use quantum simulation to investigate a (2+1)D Z2 lattice gauge theory with dynamical matter and an explicit magnetic plaquette interaction, spanning strongly confined and nonperturbative deconfined regimes. Using 63 superconducting qubits, including 12 ancillas, we evolve initially localized strings with static or dynamical endpoint charges. Spatially resolved measurements reveal rapid charge and flux spreading in the deconfined regime, enhanced matter occupation in the string interior near the pair-creation resonance, and suppressed spreading at strong electric fields. String-path occupations further probe transverse rearrangements between configurations connected by plaquette operations. Retaining separate matter and gauge degrees of freedom makes local Gauss-law constraints directly accessible for error detection. Combining these constraints with ancilla checks and noise rescaling, we measure dynamics in circuits containing up to 15 second-order Trotter steps. Our results establish quantum simulation as a practical approach to exploring nonperturbative string dynamics in two spatial dimensions, with gauge redundancy serving as an experimental resource.