Toward Scalable Two-Dimensional Fluxonium Quantum Processors: Challenges and Solutions
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- Speaker: Lijing Jin (Quantum Science Center of Guangdong-Hong Kong-Macao Greater Bay Area, China)
- Event: Quantum Technology Workshop 2026
Fluxonium qubits combine long coherence times with strong anharmonicity, making them a promising platform for scalable superconducting quantum processors. While recent experiments have demonstrated high-fidelity operations in multi-qubit fluxonium–transmon–fluxonium (FTF) architectures, extending these systems to highly connected two-dimensional (2D) architectures remains challenging. Key obstacles include the trade-offs between coupling strength, crosstalk suppression, and qubit spacing required for scalable wiring, as well as capacitive loading that fundamentally limits achievable qubit–coupler interactions.
This talk presents a quantitative design framework for scalable 2D fluxonium quantum processors. We develop a system-level design methodology based on double-transmon couplers (DTCs) that establishes quantitative relationships between circuit design parameters and processor-level performance [1]. In parallel, an analytical framework identifies the parasitic capacitances of Josephson junctions and Josephson junction arrays as the dominant origin of capacitive loading, while revealing that optimized qubit-pad geometries can effectively mitigate this limitation [2]. Together, these results establish practical design principles for realizing ultrafast, high-fidelity two-qubit gates in highly connected 2D architectures and provide a systematic pathway toward scalable fluxonium quantum processors.
[1] Guo Xuan Chan, Wangwei Lan, Tenghui Wang, Xizheng Ma, Chunqing Deng*, Lijing Jin*. "System-Level Design of Scalable Fluxonium Quantum Processors with Double-Transmon Couplers." arXiv:2604.26373 (2026).
[2] Quan Guan, Guo Xuan Chan, Xu Dou, Chunqing Deng*, Lijing Jin*. "Capacitive Loading in Two-dimensional Fluxonium Quantum Processors." arXiv:2607.22138 (2026).