Scalable Fluxonium Quantum Processors via Tunable-Coupler Architecture
Abstract
Superconducting quantum processors have largely converged on transmon-based architectures, while alternative qubit modalities with intrinsic error protection have lacked a demonstrated path to scalable system integration. In particular, although tunable-coupler-mediated interactions have been validated for small fluxonium systems, it remains unclear whether such designs can be scaled to a multi-qubit lattice. Here, we establish a scalable fluxonium processor architecture based on a modular qubit-coupler unit cell engineered to suppress residual interactions and spectator errors in a many-qubit lattice. The system enables parallel single-qubit gate fidelities approaching 99.99% and two-qubit CZ gate fidelities around 99%. With an optimized gate duration of 32 ns, the best CZ gate fidelity reaches 99.9%. We further validate this architecture in a 22-qubit processor based on the same configuration, where parallel operations enable the deterministic generation of Greenberger-Horne-Zeilinger states involving up to 10 qubits. Together, these results demonstrate that the fluxonium-tunable-coupler unit cell composes without emergent interaction pathologies and establish fluxonium as a scalable superconducting qubit platform.
Cite
@article{arxiv.2604.13363,
title = {Scalable Fluxonium Quantum Processors via Tunable-Coupler Architecture},
author = {Ze Zhan and Zishuo Li and Fei Wang and Wangwei Lan and Xianchuang Pan and Liang Xiang and Xu Dou and Ran Gao and Guicheng Gong and Yanbo Guo and Quan Guan and Lijuan Hu and Ruizhi Hu and Honghong Ji and Lijing Jin and Yongyue Jin and Chengyao Li and Kannan Lu and Lu Ma and Xizheng Ma and Hongcheng Wang and Jiahui Wang and Huijuan Zhan and Tao Zhou and Xing Zhu and Chunqing Deng and Tenghui Wang},
journal= {arXiv preprint arXiv:2604.13363},
year = {2026}
}