Design and fabrication of a granular aluminum fluxonium qubit

ORAL

Abstract

Superconducting materials with low microwave losses and high kinetic inductance are a valuable resource in quantum circuit design, enabling the design of so-called superinductors, which can provide electromagnetic environments with characteristic impedance larger than the resistance quantum RQ = 6.5 kΩ. To implement superinductors, a promising alternative to the predominantly used mesoscopic Josephson junction arrays is granular aluminum (grAl) [1]. Its microstructure consists of pure aluminum grains embedded in an AlOx matrix, effectively forming a compact self-assembled Josephson junction network [2]. We present a superconducting fluxonium qubit employing a superinductor with impedance Z > RQ, fabricated from a grAl thin film, in-situ integrated with a conventional Al/AlOx/Al Josephson junction. The measured qubit spectrum is in good agreement with the fluxonium Hamiltonian [3].

[1] L. Grünhaupt et al., Phys. Rev. Lett. 121, 117001 (2018)
[2] N. Maleeva et al., Nat. Commun. 9, 3889 (2018)
[3] L. Grünhaupt and M. Spiecker et al., arXiv:1809.10646 (2018)

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Presenters

  • Lukas Gruenhaupt

    Physikalisches Institut, Karlsruhe Institute of Technology, Karlsruhe Institute of Technology

Authors

  • Lukas Gruenhaupt

    Physikalisches Institut, Karlsruhe Institute of Technology, Karlsruhe Institute of Technology

  • Martin Spiecker

    Physikalisches Institut, Karlsruhe Institute of Technology, Karlsruhe Institute of Technology

  • Daria Gusenkova

    Karlsruhe Institute of Technology

  • Nataliya Maleeva

    Physikalisches Institut, Karlsruhe Institute of Technology, Karlsruhe Institute of Technology

  • Sebastian T. Skacel

    Karlsruhe Institute of Technology

  • Ivan Takmakov

    Karlsruhe Institute of Technology

  • Francesco Valenti

    Karlsruhe Institute of Technology

  • Patrick Winkel

    Physikalisches Institut, Karlsruhe Institute of Technology, Karlsruhe Institute of Technology

  • Hannes Rotzinger

    Karlsruhe Institute of Technology

  • Alexey Ustinov

    Karlsruhe Institute of Technology, Institute of Physics, Karlsruhe Institute of Technology

  • Ioan-Mihai Pop

    Karlsruhe Institute of Technology, Physikalisches Institut, Karlsruhe Institute of Technology, Physics, Karlsruhe Institute of Technology, Physikalisches Institut, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany