论文标题
构建对配对代码的偏见操作
Construction of Bias-preserving Operations for Pair-cat Code
论文作者
论文摘要
具有去极化误差的易耐故障量子计算通常需要要求误差阈值和资源开销。如果操作可以维持高噪声偏置 - 以小flip误差为主 - 我们可以以更有利的误差阈值来实现硬件有效的耐故障量子计算。与两级物理系统不同,多级系统(例如谐波振荡器)可以实现一组理想的保留偏见的量子操作,同时使用连续的工程耗散或汉密尔顿保护以稳定在编码子空间中。例如,用驱动散射或KERR非线性稳定的CAT代码可以具有一组有偏见的扇形门,同时连续纠正玻璃纤维性倾向误差。但是,CAT代码与对激发损失误差的连续量子误差校正不兼容,因为连续监视均衡以纠正光子损失误差是一项挑战。在这项工作中,我们将偏置的操作概括为配对代码,这可以看作是CAT代码的多模模概括,与连续的量子误差校正兼容,以相对于波音丢失和dephasing错误。我们的结果为具有偏置的操作和连续的量子误差校正均同时纠正了骨气丢失和驱动误差,为硬件有效的鲁棒量子信息处理打开了大门。
Fault-tolerant quantum computation with depolarization error often requires demanding error threshold and resource overhead. If the operations can maintain high noise bias -- dominated by dephasing error with small bit-flip error -- we can achieve hardware-efficient fault-tolerant quantum computation with a more favorable error threshold. Distinct from two-level physical systems, multi-level systems (such as harmonic oscillators) can achieve a desirable set of bias-preserving quantum operations while using continuous engineered dissipation or Hamiltonian protection to stabilize to the encoding subspace. For example, cat codes stabilized with driven-dissipation or Kerr nonlinearity can possess a set of biased-preserving gates while continuously correcting bosonic dephasing error. However, cat codes are not compatible with continuous quantum error correction against excitation loss error, because it is challenging to continuously monitor the parity to correct photon loss errors. In this work, we generalize the bias-preserving operations to pair-cat codes, which can be regarded as a multimode generalization of cat codes, to be compatible with continuous quantum error correction against both bosonic loss and dephasing errors. Our results open the door towards hardware-efficient robust quantum information processing with both bias-preserving operations and continuous quantum error correction simultaneously correcting bosonic loss and dephasing errors.