Superconducting quantum computing emerges as one of leading candidates for achieving quantum advantage. However, a prevailing challenge is the coding overhead due to limited quantum connectivity, constrained by nearest-neighbor coupling among superconducting qubits. Here, we propose a novel multimode coupling scheme using three resonators driven by two microwaves, based on the resonator-induced phase gate, to extend the ZZ interaction distance between qubits. We demonstrate a CZ gate fidelity exceeding 99.9\% within 160 ns at free spectral range (FSR) of 1.4 GHz, and by optimizing driving pulses, we further reduce the residual photon to nearly 10−3 within 100 ns at FSR of 0.2 GHz. These facilitate the long-range CZ gate over separations reaching sub-meters, thus significantly enhancing qubit connectivity and making a practical step towards the scalable integration and modularization of quantum processors. Specifically, our approach supports the implementation of quantum error correction codes requiring high connectivity, such as low-density parity check codes that paves the way to achieving fault-tolerant quantum computing.
@article{arxiv.2408.16617,
title = {Long-Range $ZZ$ Interaction via Resonator-Induced Phase in Superconducting Qubits},
author = {Xiang Deng and Wen Zheng and Xudong Liao and Haoyu Zhou and Yangyang Ge and Jie Zhao and Dong Lan and Xinsheng Tan and Yu Zhang and Shaoxiong Li and Yang Yu},
journal= {arXiv preprint arXiv:2408.16617},
year = {2025}
}