Scalable Fluxonium Quantum Processors via Tunable-Coupler Architecture

Quantum Physics [Submitted on 15 Apr 2026] Scalable Fluxonium Quantum Processors via Tunable-Coupler Architecture Ze Zhan, Zishuo Li, Fei Wang, Wangwei Lan, Xianchuang Pan, Liang Xiang, Xu Dou, Ran Gao, Guicheng Gong, Yanbo Guo, Quan Guan, Lijuan Hu, Ruizhi Hu, Honghong Ji, Lijing Jin, Yongyue Jin, Chengyao Li, Kannan Lu, Lu Ma, Xizheng Ma, Hongcheng Wang, Jiahui Wang, Huijuan Zhan, Tao Zhou, Xing Zhu, Chunqing Deng, Tenghui Wang 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. Subjects: Quantum Physics (quant-ph) Cite as: arXiv:2604.13363 [quant-ph]   (or arXiv:2604.13363v1 [quant-ph] for this version)   https://doi.org/10.48550/arXiv.2604.13363 Focus to learn more Submission history From: Chunqing Deng [view email] [v1] Wed, 15 Apr 2026 00:10:00 UTC (8,975 KB) Access Paper: HTML (experimental) view license Current browse context: quant-ph < prev   |   next > new | recent | 2026-04 References & Citations INSPIRE HEP NASA ADS Google Scholar Semantic Scholar Export BibTeX Citation Bookmark Bibliographic Tools Bibliographic and Citation Tools Bibliographic Explorer Toggle Bibliographic Explorer (What is the Explorer?) Connected Papers Toggle Connected Papers (What is Connected Papers?) Litmaps Toggle Litmaps (What is Litmaps?) scite.ai Toggle scite Smart Citations (What are Smart Citations?) Code, Data, Media Demos Related Papers About arXivLabs Which authors of this paper are endorsers? | Disable MathJax (What is MathJax?)