Universal Neutral Atom Quantum Computer with Individual Optical Addressing and Nondestructive Readout

Quantum computers need to perform large-scale fault-tolerant operations to fulfill their potential for transformational processing power. Achieving this will require thousands or even millions of high-fidelity quantum gates and a comparable number of qubits. Experiments with neutral-atom qubits, which are trapped and manipulated using lasers, have shown that this approach can deliver high two-qubit gate (CZ) fidelities and scalable operations. However, in these experiments, the gates are driven by lasers that do not individually address each qubit, and universal computation is achieved by physically moving the qubits mid-circuit. This relatively slow method could significantly increase runtimes for practical large-scale computations. In this work, we demonstrate a universal neutral-atom quantum computer where gate rates are limited by optical switching times rather than qubit shuttling, by individually addressing tightly focused laser beams to an array of single atoms. We achieve a CZ gate fidelity of 99.35(4)% and local single-qubit RZ gate fidelity of 99.902(8)%, in both cases accounting for any leakage out of the computational basis. Additionally, we show nondestructive readout of alkali-atom qubits with only 0.9(3)% loss, which improves operational speed. This technique also allows us to measure a best-in-class CZ fidelity of 99.73(3)% when excluding atom-loss events, which could potentially be managed through erasure conversion. Overall, our results mark a crucial step toward large-scale, fault-tolerant neutral-atom quantum computers capable of performing computations on practical timescales.