Realization of High-Fidelity Perfect Entanglers between Remote Superconducting Quantum Processors
Juan Song, Shuang Yang, Pei Liu, Huili Zhang, Guangming Xue, Zhenyu Mi, Wen-Gang Zhang, Fei Yan, Yirong Jin, Haifeng Yu · Physical Review Letters · 2025
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.