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

D. K. Weiss, Helin Zhang, Chunyang Ding, Yuwei Ma, David I. Schuster, Jens Koch

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


Long coherence times, large anharmonicity, and robust charge-noise insensitivity render fluxonium qubits an interesting alternative to transmons. Recent experiments have demonstrated record coherence times for low-frequency fluxonium qubits. Here, we propose a galvanic coupling scheme with flux-Tunable XX coupling. To implement a high-fidelity entangling iSWAP gate, we modulate the strength of this coupling and devise variable-Time identity gates to synchronize required single-qubit operations. Both types of gates are implemented using strong ac flux drives, lasting for only a few drive periods. We employ a theoretical framework capable of capturing qubit dynamics beyond the rotating-wave approximation as required for such strong drives. We predict an open-system fidelity of F>0.999 for the iSWAP gate under realistic conditions.

Original languageEnglish (US)
Article number040336
JournalPRX Quantum
Issue number4
StatePublished - Oct 2022

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Computer Science(all)
  • Applied Mathematics
  • Mathematical Physics
  • Electronic, Optical and Magnetic Materials
  • Electrical and Electronic Engineering


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