发表机构
The University of Sydney; Ecole Polytechnique Fédérale de Lausanne; Sungkyunkwan University; IBM Quantum, T. J. Watson Research Center; IBM Denmark（悉尼大学; 洛桑联邦理工学院; 成均馆大学; IBM量子T.J.沃森研究中心; IBM丹麦）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究在含156个超导量子比特的重六角晶格处理器上，通过噪声感知量子纠错策略，使纠错存储与基于测量的逻辑的性能分别提升最高35%、56%，并实现了高保真容错逻辑。
AI 中文摘要
大规模量子计算需要高保真的纠错存储与容错逻辑操作。为了利用超导电路实现这些功能，量子处理器需要大量以低错误率运行的组件。实际中，单片超导器件的制造会导致组件性能不可避免地存在异质性，量子计算机必须适配这种情况。我们在由156个超导量子比特组成的重六角晶格阵列上实现了大型动态罗盘码的运行策略，利用了整个单片量子处理器，并重新设计了测量调度以排除性能不佳的组件。在存储实验中，通过使用噪声感知解码器，结合排除性能最差的量子比特和耦合器的策略，以及对泄漏错误概率低的 shots（量子态制备与测量的单次运行）进行后选择，我们实现了逻辑错误概率最高达35%的改进。除了存储结果，当将这些策略应用于基于测量的逻辑时，我们在稳定性实验中观察到性能增益最高达56%。此外，我们通过格点手术实现了高保真容错逻辑，通过预选择过滤技术，我们可以获得高于77%的贝尔保真度，而使用排他解码的进一步逻辑间隙后选择将这些保真度提升至高于97%。我们的实验表明，在存在性能不佳组件的单片超导量子处理器上，通过采用一套噪声感知量子纠错策略，容错量子存储与逻辑的关键元件可维持高性能。
英文摘要
Large quantum computations require high-fidelity error-corrected memory and fault-tolerant logical operations. To achieve these with superconducting circuits, quantum processors will need many components operating with low error rates. In practice, fabrication of monolithic superconducting devices produces unavoidable heterogeneity in component performance, which the quantum computer must accommodate. We implement strategies to operate a large dynamic compass code on an array of 156 superconducting qubits arranged on a heavy-hexagonal lattice, making use of the entire monolithic quantum processor and redesigning our measurement schedule to exclude underperforming components. We demonstrate improvements of up to $35\%$ in logical error probabilities for a memory experiment by using a noise-informed decoder combined with strategies to exclude the worst-performing qubits and couplers, along with post-selecting on shots with a low probability of leakage errors. In addition to these memory results, we also observe performance gains of up to $56\%$ when these strategies are applied to measurement-based logic, demonstrated by stability experiments. We furthermore demonstrate high-fidelity fault-tolerant logic through lattice surgery. Through pre-selection filtering techniques, we can obtain Bell fidelities above $77\%$, and further logical gap post-selection using exclusive decoding increases these fidelities to above $97\%$. Our experiments demonstrate that high performance can be maintained in key elements of fault-tolerant quantum memory and logic when working on monolithic superconducting quantum processors with underperforming components, by using a suite of noise-informed quantum error correction strategies.
Comments28 pages, 20 figures, 5 tables
