标题： 在超导量子比特上实现两个距离三重复码的格子手术 显示英文标题

标题： Realizing Lattice Surgery on Two Distance-Three Repetition Codes with Superconducting Qubits

摘要： 量子错误校正对于量子计算机能够使用数百个逻辑量子比特容错地执行算法是必要的。 最近的实验已经展示了单个逻辑量子比特状态保持的亚阈值错误率。 此外，实现通用量子计算需要实现逻辑纠缠门。 格子手术为实施此类门提供了一种实用的方法，特别是在平面量子处理器布局中。 在本工作中，我们通过分割一个距离为三的表面码量子比特，演示了两个距离为三的重复码量子比特之间的格子手术。 使用对位翻转错误容错的量子电路，我们实现了解码后的$ZZ$逻辑双量子比特可观测量的值相比类似的非编码电路有所提高。 通过将表面码量子比特准备在由变化的极角参数化的初始状态，我们评估了格子手术操作在逻辑布洛赫球上的非主方向状态的性能，并利用逻辑双量子比特层析技术重建了该操作的泡利转移矩阵。 通过这种方式，我们展示了基于超导电路的更大距离代码上格子手术操作所需的功能构建模块。 显示英文摘要

摘要： Quantum error correction is needed for quantum computers to be capable of fault-tolerantly executing algorithms using hundreds of logical qubits. Recent experiments have demonstrated subthreshold error rates for state preservation of a single logical qubit. In addition, the realization of universal quantum computation requires the implementation of logical entangling gates. Lattice surgery offers a practical approach for implementing such gates, particularly in planar quantum processor layouts. In this work, we demonstrate lattice surgery between two distance-three repetition-code qubits by splitting a single distance-three surface-code qubit. Using a quantum circuit fault-tolerant to bit-flip errors, we achieve an improvement in the value of the decoded $ZZ$ logical two-qubit observable compared to a similar non-encoded circuit. By preparing the surface-code qubit in initial states parametrized by a varying polar angle, we evaluate the performance of the lattice surgery operation for non-cardinal states on the logical Bloch sphere and employ logical two-qubit tomography to reconstruct the Pauli transfer matrix of the operation. In this way, we demonstrate the functional building blocks needed for lattice surgery operations on larger-distance codes based on superconducting circuits.