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arXiv · 2505.08606

High-contrast interaction between remote superconducting qubits mediated by multimode cable coupling

Jiajian Zhang·Ji Chu·Jingjing Niu·Youpeng Zhong·Dapeng Yu
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Abstract

Superconducting quantum processors offer a promising path towards practical quantum computing. However, building a fault-tolerant quantum computer with millions of superconducting qubits is hindered by wiring density, packaging constraints and fabrication yield. Interconnecting medium-scale processors via low-loss superconducting links provides a promising alternative. Yet, achieving high-fidelity two-qubit gates across such channels remains difficult. Here, we show that a multimode coaxial cable can mediate high-contrast interaction between spatially separated super-conducting qubits. Leveraging interference between cable modes, we can implement high-fidelity controlled-Z and ZZ-free iSWAP gates by simply modulating qubit frequencies. Numerical simulations under realistic coherence and coupling parameters predict fidelities above 99% for both gate schemes. Our approach provides a versatile building block for modular superconducting architectures and facilitates distributed quantum error correction and large-scale fault-tolerant quantum computing.

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Jiajian Zhang, Ji Chu, Jingjing Niu, Youpeng Zhong, Dapeng Yu. 2025-05-13. High-contrast interaction between remote superconducting qubits mediated by multimode cable coupling. https://arxiv.org/abs/2505.08606

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