AI 中文总结
本研究实现了一款采用集总元件谐振器耦合器的四连通性磁通量子比特量子处理器，其单、两量子比特门保真度优异，成功制备多量子比特纠缠态，为高连通性量子处理器及量子纠错架构提供了可行方案。
AI 中文摘要
基于磁通量子比特（fluxonium）的量子处理器面临的核心挑战是将量子比特的连通性扩展至适配量子纠错的二维晶格。本研究展示了一款采用集总元件谐振器耦合器的磁通量子比特量子处理器，首次实现了具有寄生相互作用抑制效果的四连通性单元晶胞。在同步随机基准测试实验中，我们实现了并行单量子比特门保真度超过99.9%，同时所有耦合量子比特对的残余静态ZZ相互作用低于1 kHz；我们还实现了谐振器诱导相位（RIP）门，通过交错随机基准测试测得两量子比特门保真度超过99%。为消除两量子比特操作中观测到的旁观误差，我们实现了重聚焦RIP门，在多量子比特连通性存在的情况下恢复了相干控制。此外，我们制备了最多五个量子比特的Greenberger-Horne-Zeilinger态，其层析保真度为90%，验证了单元晶胞内的多量子比特纠缠。这些结果确立了磁通量子比特-谐振器-磁通量子比特架构是实现高连通性磁通量子比特处理器的可行方案，并为构建适配量子纠错的可扩展处理器架构提供了路径。
英文摘要
A central challenge in fluxonium-based quantum processors is the extension of the qubit connectivity to two-dimensional lattices compatible with quantum code-error correction. Here, we present a fluxonium quantum processor that employs lumped-element resonator couplers which realizes, for the first time, a connectivity-four unit cell with suppressed parasitic interactions. We achieve parallel single-qubit gate fidelities exceeding 99.9 % in simultaneous randomized benchmarking experiments, while maintaining residual static ZZ interactions below 1 kHz across all coupled qubit pairs. We implement resonator-induced phase (RIP) gates and benchmark two-qubit gate fidelities exceeding 99 % using interleaved randomized benchmarking. To cancel spectator errors observed in two-qubit operations, we implement a refocused RIP gate, recovering coherent control in the presence of multi-qubit connectivity. Furthermore, we prepare Greenberger-Horne-Zeilinger states of up to five qubits with a tomographic fidelity of 90 %, verifying multi-qubit entanglement within the unit cell. These results establish the fluxonium-resonator-fluxonium architecture as a viable approach to realizing densely connected fluxonium processors and provide a scalable path toward quantum error-correction-compatible processor architectures.
Comments14 pages, 7 figures
