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Realization of High-Fidelity Perfect Entanglers between Remote Superconducting Quantum Processors

Juan Song1,2,3,*, Shuang Yang1,*, Pei Liu1,4,*, Hui-Li Zhang1, Guang-Ming Xue1,5, Zhen-Yu Mi1,†, Wen-Gang Zhang1,‡, Fei Yan1, Yi-Rong Jin1,§ et al.

Hai-Feng Yu1,5

  • *These authors contributed equally to this work.
  • †Contact author: mizy@baqis.ac.cn
  • ‡Contact author: zhangwg@baqis.ac.cn
  • §Contact author: jinyr@baqis.ac.cn
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Phys. Rev. Lett. 135, 050603 – Published 30 July, 2025

DOI: https://doi.org/10.1103/npr7-b7kq

Abstract

Superconducting qubit systems, one of the leading candidates for universal quantum computing, face scalability challenges such as frequency crowding, wiring complexity, and packaging problems. Distributed quantum computing offers a viable strategy for constructing larger quantum information processing systems. Yet, direct universal quantum gates between remote qubits—critical to distributed architectures—remain unrealized. Here, we demonstrate direct high-fidelity entangling gates between two remote superconducting quantum processors separated by a 30 cm distance, utilizing standing-wave modes in their connecting coaxial cable. We achieve cross-entropy benchmarking fidelities of (99.15±0.02)% and (98.03±0.04)% for the controlled-not and controlled-z gates, respectively, outperforming state transfer and feedback-based protocols in fidelity and efficiency. This advancement significantly enhances the prospect of universal distributed quantum information processing, which is the critical step toward future large-scale quantum systems.

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Phys. Rev. Lett. 135, 050603– Published 30 July, 2025
  • Received 8 October 2024
  • Revised 2 April 2025
  • Accepted 8 July 2025
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