Repeated quantum error correction on a continuously encoded qubit by real-time feedback.
Repeated quantum error correction on a continuously encoded qubit by real-time feedback.
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DOI：
10.1038/ncomms11526
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发表时间：
2016-05-05
影响因子：
16.6
通讯作者：
Taminiau TH
中科院分区：
文献类型：
--
作者：
Cramer J;Kalb N;Rol MA;Hensen B;Blok MS;Markham M;Twitchen DJ;Hanson R;Taminiau TH
面对错误的可靠量子信息处理是一个重大的基础和技术挑战。量子纠错通过在多个物理量子比特中编码逻辑量子比特（量子比特）来保护量子态。为了与通用容错计算兼容，状态必须始终保持编码，并且错误必须得到主动纠正。在这里，我们使用钻石量子处理器在连续保护的逻辑量子比特上演示了这种主动纠错。我们将逻辑量子比特编码为三个长寿命的核自旋，通过非破坏性测量重复检测相位误差，并通过实时反馈进行校正。主动纠错的量子比特对错误是鲁棒的，并且编码的量子叠加态被保留超过编码中的最佳物理量子比特的自然失相时间。这些结果建立了一个强大的平台，研究不同类型的噪声下的纠错，并标志着容错量子信息处理的重要一步。 大规模的量子信息处理需要不断地保护量子态不受错误的影响。在这里，作者演示了使用钻石量子处理器改善量子态失相时间的主动量子纠错。
Reliable quantum information processing in the face of errors is a major fundamental and technological challenge. Quantum error correction protects quantum states by encoding a logical quantum bit (qubit) in multiple physical qubits. To be compatible with universal fault-tolerant computations, it is essential that states remain encoded at all times and that errors are actively corrected. Here we demonstrate such active error correction on a continuously protected logical qubit using a diamond quantum processor. We encode the logical qubit in three long-lived nuclear spins, repeatedly detect phase errors by non-destructive measurements, and apply corrections by real-time feedback. The actively error-corrected qubit is robust against errors and encoded quantum superposition states are preserved beyond the natural dephasing time of the best physical qubit in the encoding. These results establish a powerful platform to investigate error correction under different types of noise and mark an important step towards fault-tolerant quantum information processing. Large-scale quantum information processing requires the continuous protection of quantum states against errors. Here, the authors demonstrate active quantum error correction that improves the dephasing time of quantum states using a diamond quantum processor.