论文标题
通过量子错误检测和抑制，比古典的Grover搜索更好
Better-than-classical Grover search via quantum error detection and suppression
论文作者
论文摘要
Grover的搜索算法是最早具有可证明的量子优势的量子算法之一。它构成了众多量子应用的骨干，并广泛用于基准测试工作。在这里，我们使用两个不同的IBM超导型Transmon Qubit平台，在迄今为止最多显示的最大量表中，最大量表的完整Grover搜索算法报告了比古典的成功概率更好。通过可靠的动力学脱钩脉冲序列抑制误差，在四个QUIT量表上启用了这一点，否则，我们将不会观察到比古典结果更好的结果。在使用测量误差缓解后，会进一步改进，但后者本身不足以实现比古典性更好的表现。对于两个量子位，我们通过使用[[4,2,2]]量子错误检测（QED）代码证明了99.5％的成功概率。这构成了通过QED证明量子算法的。一路上，我们引入了算法错误层析成像，这是一种独立感兴趣的方法，它为整个量子算法中累积的错误提供了整体视图，该误差是通过用于编码电路的QED代码检测到的误差过滤的。我们证明，算法误差断层扫描提供了基于振幅阻尼，去极化和去极化的组合的误差模型的严格测试。
Grover's search algorithm is one of the first quantum algorithms to exhibit a provable quantum advantage. It forms the backbone of numerous quantum applications and is widely used in benchmarking efforts. Here, we report better-than-classical success probabilities for a complete Grover search algorithm on the largest scale demonstrated to date, of up to five qubits, using two different IBM superconducting transmon qubit platforms. This is enabled, on the four and five-qubit scale, by error suppression via robust dynamical decoupling pulse sequences, without which we do not observe better-than-classical results. Further improvements arise after the use of measurement error mitigation, but the latter is insufficient by itself for achieving better-than-classical performance. For two qubits, we demonstrate a success probability of 99.5% via the use of the [[4,2,2]] quantum error-detection (QED) code. This constitutes a demonstration of quantum algorithmic breakeven via QED. Along the way, we introduce algorithmic error tomography, a method of independent interest that provides a holistic view of the errors accumulated throughout an entire quantum algorithm, filtered via the errors detected by the QED code used to encode the circuit. We demonstrate that algorithmic error tomography provides a stringent test of an error model based on a combination of amplitude damping, dephasing, and depolarization.
