两超导比特高保真度控制相位门(特邀)

doi:10.3969/j.issn.1007-5461.2026.04.004

摘要/Abstract

摘要： 超导电路因其成熟的微纳加工技术而具备良好的可扩展性, 现已成为实现量子计算最具前景的物理系统之一。尽管超导量子比特平台在量子计算领域已取得诸多进展, 但在多量子比特量子处理器中, 以高于容错阈值的保真度在任意两个远距离量子比特之间执行通用量子门操作仍具挑战性, 而该能力对量子算法的实现却至关重要。为此, 本文采用多个频率可调量子比特与一个谐振腔耦合的架构实现了该目标。任意两个量子比特间的受控相位门可通过比特与谐振腔之间的光子交换过程来实现, 该过程需调节其中一个量子比特与谐振腔之间的耦合强度。数值模拟结果表明, 在较短的门操作时间内, 该方法可实现超过容错阈值的门保真度, 这些特性使其在大规模全连通超导量子处理器中执行逻辑操作时具有显著优势。

关键词: 量子计算, 控制相位门, 量子过程层析, 超导量子比特

Abstract: Superconducting circuits are particularly appealing as platforms for quantum computing due to the good scalability of their associated microfabrication techniques. Significant progress has been made in superconducting qubits, however, performing universal quantum gate operations between an arbitrary pair of distant qubits with fidelity above the fault-tolerant threshold remains a challenging goal in multi-qubit quantum processors, which is crucial for executing quantum algorithms. Here, we present a mechanism and its experimental demonstration for achieving this objective by adopting an architecture in which multiple frequency-tunable qubits are coupled with a resonator. A controlled-phase gate between any two qubits is realized through a coherent photon exchange process mediated by the resonator, and tailored by dynamically adjusting the coupling strength between one qubit and the resonator. Numerical simulations indicate that, according to the proposed mechanism, the gate fidelity exceeding the fault-tolerant threshold can be achieved within a considerable gate operation time. These characteristics render the approach highly suitable for implementing logical operations in large-scale superconducting quantum processors with all-to-all connectivity.

Key words: quantum computation, controlled-phase gate, quantum process tomography, superconducting quantum qubits

中图分类号:

O431.2

宁文, 杨贞标, 郑仕标. 两超导比特高保真度控制相位门(特邀)[J]. 量子电子学报, 2026, 43(4): 539-548.

NING Wen , YANG Zhenbiao, ZHENG Shibiao . A high⁃fidelity controlled⁃phase gate betweentwo superconducting qubits(Invited)[J]. Chinese Journal of Quantum Electronics, 2026, 43(4): 539-548.

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