Verifying the analogy between transversely coupled spin-1/2 systems and inductively-coupled fluxoniums

We report a detailed characterization of two inductively coupled superconducting fluxonium qubits for implementing high-fidelity cross-resonance gates. Our circuit stands out because it behaves very closely to the case of two transversely coupled spin- $1/2$ systems. In particular, the generally unw...

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Bibliographic Details
Main Authors: Wei-Ju Lin, Hyunheung Cho, Yinqi Chen, Maxim G Vavilov, Chen Wang, Vladimir E Manucharyan
Format: Article
Language:English
Published: IOP Publishing 2025-01-01
Series:New Journal of Physics
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Online Access:https://doi.org/10.1088/1367-2630/adb77b
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Summary:We report a detailed characterization of two inductively coupled superconducting fluxonium qubits for implementing high-fidelity cross-resonance gates. Our circuit stands out because it behaves very closely to the case of two transversely coupled spin- $1/2$ systems. In particular, the generally unwanted static ZZ -term due to the non-computational transitions is nearly absent despite a strong qubit–qubit hybridization. Spectroscopy of the non-computational transitions reveals a spurious LC -mode arising from the combination of the coupling inductance and the capacitive links between the terminals of the two-qubit circuit. Such a mode has a minor effect on the present device, but it must be carefully considered for optimizing future multi-qubit designs.
ISSN:1367-2630