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Flux-Tunable Hybridization in a Double Quantum Dot Interferometer

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Abstract

Tuning the hybridization between fermionic modes with magnetic flux to distinguish parity states is crucial for topological quantum computation [1,2]. We demonstrate tuning of the tunnel coupling between two such modes with flux, implemented in a phase-coherent loop comprising two quantum dots in an InSbAs two-dimensional electron gas. Using reflectometry at radio frequencies on the dots’ plunger gate electrodes, we extract the inter-dot tunnel coupling as a function of flux through the loop, observing oscillations of the coupling with a periodicity of a flux quantum across numerous inter-dot charge transitions. This is found to be consistent with reflectometry measurements of the Aharonov-Bohm effect in the open loop measured with the tunnel barriers lowered. Next, in different tunnel coupling regimes we benchmark the contrast of these hybridization oscillations, observing that they vary depending on the modes involved, but are generally not suppressed at their minima. These results establish the feasibility and contrast limitations of conducting parity readout of hybrid qubits with tunnel couplings tuned by flux.

[1] T. B. Smith, M. C. Cassidy, D. J. Reilly, S. D. Bartlett, and A. L. Grimsmo, Dispersive Readout of Majorana Qubits, PRX Quantum 1, 10.1103/prxquantum.1.020313 (2020).

[2] M. Leijnse and K. Flensberg, Parity qubits and poor man's Majorana bound states in double quantum dots, Physical Review B 86, 10.1103/PhysRevB.86.134528 (2012).

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Presenters

  • Christian G Prosko

    QuTech (Delft University of Technology), Delft University of Technology

Authors

  • Christian G Prosko

    QuTech (Delft University of Technology), Delft University of Technology

  • Ivan Kulesh

    QuTech (Delft University of Technology), Delft University of Technology

  • Michael Chan

    Delft University of Technology

  • Lin Han

    Delft University of Technology, QuTech, Delft University of Technology

  • Di Xiao

    Department of Physics and Astronomy, Purdue University, Purdue University

  • Candice Thomas

    Univ. Grenoble Alpes, CEA, Leti, Grenoble, France, CEA

  • Michael J Manfra

    Purdue University, Microsoft Quantum Purdue, Purdue University, Birck Nanotechnology Center, Purdue University, West Lafayette, IN, USA; Microsoft Quantum Lab, Purdue University, West Lafayette, IN, USA, Physics and Astronomy, Purdue University, Department of Physics and Astronomy, Birck Nanotechnology Center, School of Electrical and Computer Engineering and Microsoft Quantum Lab West Lafayette, Purdue University, Department of Physics and Astronomy and Nanotechnology Center Purdue University, Microsoft Quantum Lab West Lafayette, Department of Physics and Astronomy, Birck Nanotechnology Center, School of Materials Engineering and School of Electrical and Computer Engineering, Purdue University

  • Leo P Kouwenhoven

    Delft University of Technology, Qutech, Delft University of Technology

  • Srijit Goswami

    Delft University of Technology

  • Filip K Malinowski

    Delft University of Technology