Understanding drive-induced state transitions in fluxonium: part 1/2

ORAL

Abstract

Fluxonium is a promising qubit platform with long coherence times. Systematically achieving fast, high-fidelity readout in fluxonium qubits is crucial to their scaling up. Stronger coupling and a stronger drive through the readout resonator dispersively coupled to the qubit typically improve the signal-to-noise ratio of the readout. However, recent work has shown that drives can induce undesired measurement-induced transitions, degrading the quantum non-demolition (QND) character of the readout.

In this presentation, we experimentally study dispersive readout of fluxonium qubits. We use Floquet calculations and multilevel branch analysis to model and understand the observed features. In part 1 of this two-part talk, we will discuss the loss of QND-ness when driving near the resonator frequency, as a function of resonator drive power and qubit flux.

**This work was supported by the Army Research Office under Grant No. W911NF2310101. Part of this work was performed at nano@stanford RRID:SCR_026695. Some devices used in this work were fabricated and packaged by the Superconducting Qubits at Lincoln Laboratory (SQUILL) Foundry at MIT Lincoln Laboratory, with funding from the Laboratory for Physical Sciences (LPS) Qubit Collaboratory. 

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Presenters

  • Paul R Varosy

    • Stanford University / SLAC National Accelerator Laboratory

Authors

  • Paul R Varosy

    • Stanford University / SLAC National Accelerator Laboratory

  • Chuyao Tong

    • Stanford University

  • Chunyang Ding

    • Stanford University

  • Nikitha Jain

    • Stanford University

  • Alex Arimoto Chapple

    • Universite de Sherbrooke

  • Boris Varbanov

    • University of Sherbrooke
    • Université de Sherbrooke
    • Universite de Sherbrooke

  • Alexander McDonald

    • Université de Sherbrooke

  • Sai Pavan Chitta

    • Northwestern University

  • Danyang Chen

    • Northwestern University

  • Tianpu Zhao

    • Northwestern University

  • Alexandre Blais

    • Université de Sherbrooke
    • University of Sherbrooke
    • Universite de Sherbrooke
    • Institut Quantique, Département de Physique, Université de Sherbrooke

  • Jens Koch

    • Northwestern University

  • David I Schuster

    • Stanford University / SLAC National Accelerator Laboratory
    • University of Chicago
    • Stanford