Site-selective cavity readout and classical error correction of a 5-bit atomic register*

Neutral atom arrays coupled to optical cavities are a promising platform for quantum information science. Optical cavities enable fast and non-destructive readout of individual atomic qubits; however, scaling up to arrays of qubits remains challenging. We recently addressed this by using locally controlled excited-state Stark shifts to achieve site-selective hyperfine-state cavity readout across a 10-site array. To further speed up array readout, we demonstrated adaptive search strategies utilizing global/subset checks, paving the way for faster quantum error correction cycles. As a step toward fault tolerance, we demonstrated repeated rounds of classical error correction, showing exponential suppression of logical error and extending logical memory fivefold beyond the single-bit idling lifetime.