Fast High-Fidelity Gates for Galvanically-Coupled Fluxonium Qubits Using Strong Flux Modulation

Long coherence times, large anharmonicity, and robust charge-noise insensitivity render fluxonium qubits an interesting alternative to transmons. Recent experiments have demonstrated record times for low-frequency qubits. Here, we propose a galvanic coupling scheme with flux-tunable XX coupling. To implement high-fidelity entangling iSWAP gate, modulate the strength of this devise variable-time identity gates synchronize required single-qubit operations. Both types are implemented using strong ac flux drives, lasting only few drive periods. We employ theoretical framework capable capturing qubit dynamics beyond rotating-wave approximation as such drives. predict open-system fidelity F>0.999 gate under realistic conditions.3 MoreReceived 14 July 2022Accepted 18 November 2022DOI:https://doi.org/10.1103/PRXQuantum.3.040336Published by American Physical Society terms Creative Commons Attribution 4.0 International license. Further distribution work must maintain attribution author(s) published article's title, journal citation, DOI.Published SocietyPhysics Subject Headings (PhySH)Research AreasQuantum controlQuantum gatesQuantum information solid state qubitsPhysical SystemsSuperconducting qubitsQuantum InformationCondensed Matter, Materials & Applied Physics