Experimental study of flux noise in nanowire transmons subject to an applied magnetic field

ORAL

Abstract

Flux noise is generally the dominant dephasing mechanism in transmon qubits using SQUID loops as a tunable inductive element. Continuing experimental research ambitions to elucidate the microscopic origin and mitigation of flux noise. In this work, we experimentally investigate flux noise using an unconventional knob for circuit QED: an applied in-plane magnetic field. We first present various changes introduced to our circuit QED system and setup to further extend the field compatibility of resonators and nanowire transmons beyond 70 mT and to reduce extrinsic noise. Next, we use standard coherence measurements and sensitivity analysis on and off flux sweetspots to investigate the dependence of flux noise on field applied along the axis of the two constituent nanowire junctions.

*Research funded by the ERC Synergy Grant QC-lab, Microsoft Corporation, and the Danish National Research Foundation.

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Presenters

  • Thijs Stavenga

    • QuTech and Kavli Institute of Nanoscience, Delft University of Technology

Authors

  • Thijs Stavenga

    • QuTech and Kavli Institute of Nanoscience, Delft University of Technology

  • Florian Luthi

    • QuTech and Kavli Institute of Nanoscience, Delft University of Technology

  • Joep Assendelft

    • QuTech and Kavli Institute of Nanoscience, Delft University of Technology

  • David Thoen

    • Department of Microelectronics and Kavli Institute of Nanoscience, Delft University of Technology

  • Akira Endo

    • Department of Microelectronics and Kavli Institute of Nanoscience, Delft University of Technology

  • Peter Krogstrup

    • Niels Bohr Institute, University of Copenhagen
    • Center for Quantum Devices and Station Q Copenhagen, University of Copenhagen
    • Center for Quantum Devices
    • Center for Quantum Devices, Station Q Copenhagen, Niels Bohr Institute, University of Copenhagen
    • Center for Quantum Devices and Microsoft Quantum Lab Copenhagen, Niels Bohr Institute, University of Copenhagen

  • Leonardo DiCarlo

    • QuTech and Kavli Institute of Nanoscience, Delft University of Technology
    • QuTech and Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
    • QuTech and Kavli Institute of Nanoscience Delft, Delft University of Technology