arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2309.10331quant-phcs.CC
收藏

具有Pauli噪声的表面码解码的困难性结果

Hardness results for decoding the surface code with Pauli noise

Alex Fischer, Akimasa Miyake

AI总结:

研究了在依赖于量子比特的Pauli噪声模型下表面码解码的复杂度,证明了QMLD和DQMLD分别为NP困难和#P困难,并给出了近似困难性结果。

摘要:

真实的量子计算机将受到复杂的、依赖于量子比特的噪声,而不是对所有量子比特具有相同强度的简单噪声(例如退极化噪声)。如果我们的解码算法考虑了关于特定存在噪声的先验信息,我们就能更有效地进行量子纠错。这促使我们考虑表面码解码的复杂度,其中解码问题的输入不仅是综合征测量结果,还是以每个量子比特的单量子比特Pauli错误概率形式的噪声模型。在这种设置下,我们证明了表面码的量子最大似然解码(QMLD)和简并量子最大似然解码(DQMLD)分别是NP困难和#P困难的。对于QMLD,我们直接从SAT问题进行归约;对于DQMLD,我们从#SAT问题进行归约,方法是展示如何将布尔公式转换为依赖于量子比特的Pauli噪声模型和编码该公式可满足性性质的综合征集合。我们还给出了QMLD和DQMLD的近似困难性结果。这些是最坏情况下的困难性结果,并不与许多高效的表面码解码器在平均情况下(即对于大多数综合征集合和大多数合理的噪声模型)是正确的这一经验事实相矛盾。这些困难性结果与已知的具有独立X和Z噪声的任意稳定子码的QMLD和DQMLD的困难性结果很好地类似。

英文摘要:

Real quantum computers will be subject to complicated, qubit-dependent noise, instead of simple noise such as depolarizing noise with the same strength for all qubits. We can do quantum error correction more effectively if our decoding algorithms take into account this prior information about the specific noise present. This motivates us to consider the complexity of surface code decoding where the input to the decoding problem is not only the syndrome-measurement results, but also a noise model in the form of probabilities of single-qubit Pauli errors for every qubit. In this setting, we show that quantum maximum likelihood decoding (QMLD) and degenerate quantum maximum likelihood decoding (DQMLD) for the surface code are NP-hard and #P-hard, respectively. We reduce directly from SAT for QMLD, and from #SAT for DQMLD, by showing how to transform a boolean formula into a qubit-dependent Pauli noise model and set of syndromes that encode the satisfiability properties of the formula. We also give hardness of approximation results for QMLD and DQMLD. These are worst-case hardness results that do not contradict the empirical fact that many efficient surface code decoders are correct in the average case (i.e., for most sets of syndromes and for most reasonable noise models). These hardness results are nicely analogous with the known hardness results for QMLD and DQMLD for arbitrary stabilizer codes with independent $X$ and $Z$ noise.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑