aiqbench analysis
This study demonstrates a significant architectural breakthrough for fluxonium quantum processors by achieving high-fidelity connectivity-four unit cells essential for scalable error correction. By suppressing parasitic interactions and maintaining gate fidelities above 99%, the research validates a viable path toward densely connected, fault-tolerant quantum architectures. These results directly advance the practical implementation of multi-qubit entanglement required for complex quantum algorithms.
High-Fidelity Entangled States in a Connectivity-Four Fluxonium Quantum Processor
arXiv:2608.25503v1 Announce Type: new Abstract: 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.
Authors:J. Schirk, N. Bruckmoser, S. M. Taubenberger, F. Wallner, N. J. Glaser, M. Zetzl, L. Huang, I. Tsitsilin, M. Werninghaus, L. Södergren, K. Liegener, C. M. F. Schneider, Stefan Filipp
Abstract: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.
arXiv:2608.25503 [quant-ph]
(or arXiv:2608.25503v1 [quant-ph] for this version)
https://doi.org/10.48550/arXiv.2608.25503 arXiv-issued DOI via DataCite (pending registration)
Full text under the publisher's open licence · 212 words
