论文标题

量身定制的XZZX代码偏向噪声

Tailored XZZX codes for biased noise

论文作者

Xu, Qian, Mannucci, Nam, Seif, Alireza, Kubica, Aleksander, Flammia, Steven T., Jiang, Liang

论文摘要

由于苛刻的阈值和资源要求,通用错误的量子误差校正(QEC)具有挑战性。有趣的是,当物理噪声有偏见时,我们可以根据噪声定制QEC方案以提高性能。在这里,我们研究了具有XZZX型稳定器发生器的代码家族,其中包括一组从五分码代码中概括的环状代码以及我们称为广义曲折代码(GTC)的一组拓扑代码。我们表明,如果针对偏置噪声量身定制这些XZZX代码,则具有高度Qubit的效率。为了表征代码性能,我们使用有效距离的概念,该概念将代码距离推广到有偏见的情况下,并构成了逻辑故障率的代理。我们发现,XZZX代码可以通过有偏见的噪声来实现该指标的有利资源缩放。我们还表明,XZZX代码具有非常高的阈值,可以通过随机代码实现的目的,并且可以使用匹配解码器有效地解码它们。最后,通过仅添加一个标志Qubit,XZZX代码可以在保持较大的有效距离的同时实现易于故障的QEC。结合起来,我们的结果表明,量身定制的XZZX代码为降低噪声的资源效率QEC提供了一种资源有效的方案。

Quantum error correction (QEC) for generic errors is challenging due to the demanding threshold and resource requirements. Interestingly, when physical noise is biased, we can tailor our QEC schemes to the noise to improve performance. Here we study a family of codes having XZZX-type stabilizer generators, including a set of cyclic codes generalized from the five-qubit code and a set of topological codes that we call generalized toric codes (GTCs). We show that these XZZX codes are highly qubit efficient if tailored to biased noise. To characterize the code performance, we use the notion of effective distance, which generalizes code distance to the case of biased noise and constitutes a proxy for the logical failure rate. We find that the XZZX codes can achieve a favorable resource scaling by this metric under biased noise. We also show that the XZZX codes have remarkably high thresholds that reach what is achievable by random codes, and furthermore they can be efficiently decoded using matching decoders. Finally, by adding only one flag qubit, the XZZX codes can realize fault-tolerant QEC while preserving their large effective distance. In combination, our results show that tailored XZZX codes give a resource-efficient scheme for fault-tolerant QEC against biased noise.

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