Capacitative measurement of an Andreev bound state in a quantum dot coupled to a floating superconducting island

ORAL

Abstract

We study the response of a resonator attached to a gate of a floating quantum dot coupled to a superconducting island, defined in an InAs nanowire with an epitaxial Al shell. The reflectometry signal distinguishes between the superconducting island hosting no subgap states and discrete subgap states. In the case of the superconducting island hosting no subgap states, we vary the applied magnetic field and tunnel coupling. The resonance frequency shift and changes in the quality factor at the charge transitions are simulated using a projected numerical renormalization group method, and show good quantitative agreement with the experiment. The established measurement method, as well as the simulation framework, are suitable for the study of devices consisting of multiple superconducting islands and quantum dots, such as Andreev molecules or a Kitaev chain.

*This work was supported the Netherlands Organization for Scientific Research (NWO) and Microsoft Corporation Station Q. FKM acknowledges support from NWO under Veni grant (VI.Veni.202.034).

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Presenters

  • Filip K Malinowski

    • Delft University of Technology

Authors

  • Filip K Malinowski

    • Delft University of Technology

  • Rok Zitko

    • University of Ljubljana
    • Jozef Stefan Institute

  • Damaz De Jong

    • Delft University of Technology

  • Christian G Prosko

    • Delft University of Technology

  • Zoltan Guba

    • Budapest University of Technology and Economics

  • R. K. Rupesh

    • University of Hyderabad

  • Luka Pavesic

    • University of Ljubljana
    • Jozef Stefan Institute

  • Lin Han

    • Delft University of Technology

  • Michael Chan

    • Delft University of Technology

  • Yu Liu

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

  • Peter Krogstrup

    • Microsoft Quantum Materials Lab Copenhagen
    • University of Copenhagen and Microsoft Quantum Materials Lab Copenhagen
    • ekrogst@microsoft.com
    • Quantum Materials Lab Copenhagen, Microsoft
    • Microsoft Quantum Materials Lab
    • Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen

  • Andras Palyi

    • Budapest University of Technology and Economics

  • Jonne V Koski

    • Microsoft Corp