A universal neutral-atom quantum computer with individual optical addressing and non-destructive readout

TL;DR

This paper demonstrates a scalable neutral-atom quantum computer with high-fidelity gates, individual optical addressing, and non-destructive readout, significantly improving operational speed and paving the way for large-scale fault-tolerant quantum computing.

Contribution

It introduces a neutral-atom quantum computer with individual laser addressing and non-destructive readout, achieving high gate fidelities and faster operation without atom shuttling.

Findings

CZ fidelity of 99.35% achieved

Non-destructive readout with 0.9% atom loss

CZ fidelity of 99.73% when excluding atom-loss events

Abstract

Quantum computers must achieve large-scale, fault-tolerant operation to deliver on their promise of transformational processing power [1-4]. This will require thousands or millions of high-fidelity quantum gates and similar numbers of qubits [5]. Demonstrations using neutral-atom qubits trapped and manipulated by lasers have shown that this modality can provide high two-qubit gate (CZ) fidelities and scalable operation [6-13]. However, the gates in these demonstrations are driven by lasers that do not resolve individual qubits, with universal computation enabled by physical mid-circuit shuttling of the qubits. This relatively slow operation may greatly extend runtimes for useful, large-scale computation. Here we demonstrate a universal neutral-atom quantum computer with gate rates limited by optical switching times, rather than shuttling, by individually addressing tightly focused laser beams at an array of single atoms. We achieve CZ fidelity of 99.35(4)% and local single-qubit RZ gate fidelity of 99.902(8)%. Moreover, we demonstrate non-destructive readout of alkali-atom qubits with 0.9(3)% loss, which boosts operational speed. This technique also enables us to measure a state-of-the-art CZ fidelity of 99.73(3)% when excluding atom-loss events, which may be mitigated through erasure conversion. Our results represent a critical step towards large-scale, fault-tolerant neutral-atom quantum computers that can execute computations on practical timescales.