Erasure conversion in a high-fidelity Rydberg quantum simulator
Pascal Scholl, Adam L. Shaw, Richard Bing-Shiun Tsai, Ran Finkelstein, Joonhee Choi, Manuel Endres
Abstract
Abstract 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 $$\ge 0.997{1}_{-13}^{+10}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mo>≥</mml:mo><mml:mn>0.997</mml:mn><mml:msubsup><mml:mrow><mml:mn>1</mml:mn></mml:mrow><mml:mrow><mml:mo>−</mml:mo><mml:mn>13</mml:mn></mml:mrow><mml:mrow><mml:mo>+</mml:mo><mml:mn>10</mml:mn></mml:mrow></mml:msubsup></mml:mrow></mml:math> , which improves to $$\ge 0.998{5}_{-12}^{+7}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mo>≥</mml:mo><mml:mn>0.998</mml:mn><mml:msubsup><mml:mrow><mml:mn>5</mml:mn></mml:mrow><mml:mrow><mml:mo>−</mml:mo><mml:mn>12</mml:mn></mml:mrow><mml:mrow><mml:mo>+</mml:mo><mml:mn>7</mml:mn></mml:mrow></mml:msubsup></mml:mrow></mml:math> 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 .