Erasure conversion in a high-fidelity Rydberg quantum simulator

Minimizing and understanding errors is critical for quantum science, both in noisy intermediate scale quantum (NISQ) devices ¹ and for the quest towards fault-tolerant quantum computation ^2,3. Rydberg arrays have emerged as a prominent platform in this context ⁴ with impressive system sizes ^5,6 and proposals suggesting how error-correction thresholds could be significantly improved by detecting leakage errors with single-atom resolution ^7,8, a form of erasure error conversion ^9–12. However, two-qubit entanglement fidelities in Rydberg atom arrays ^13,14 have lagged behind competitors ^15,16 and this type of erasure conversion is yet to be realized for matter-based qubits in general. Here we demonstrate both erasure conversion and high-fidelity Bell state generation using a Rydberg quantum simulator ^5,6,17,18. When excising data with erasure errors observed via fast imaging of alkaline-earth atoms ^19–22, we achieve a Bell state fidelity of ≥0.9971−13+10 , which improves to ≥0.9985−12+7 when correcting for remaining state-preparation errors. We further apply erasure conversion in a quantum simulation experiment for quasi-adiabatic preparation of long-range order across a quantum phase transition, and reveal the otherwise hidden impact of these errors on the simulation outcome. Our work demonstrates the capability for Rydberg-based entanglement to reach fidelities in the 0.999 regime, with higher fidelities a question of technical improvements, and shows how erasure conversion can be utilized in NISQ devices. These techniques could be translated directly to quantum-error-correction codes with the addition of long-lived qubits ^7,22–24.