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Entanglement of fluxonium qubits without leaving the computational space

ORAL

Abstract

The superconducting fluxonium circuit in its flux sweet spot possesses unique spectral properties. Its main qubit transition has low frequency and exceptionally long lifetime reaching 500 us [1], while the transition between its first and second excited states has an order of magnitude higher frequency and stronger coupling to a microwave field, which has been utilized in a fast controlled-Z gate [2, 3]. On the other hand, strong anharmonicity of the fluxonium also simplifies qubit control by driving transitions in the computational subspace to perform two-qubit gates. The first example discussed here is a controlled-X gate reminiscent of the cross-resonance gate in transmons [4]. It is activated by driving at the frequency of the target qubit and requires two independent controls. The second example is a swapping gate operation in the 00-11 subspace activated by a high-power drive at half the frequency of the 00-11 two-photon transition, which can be compared to bSWAP gate with transmons [5].

[1] L. B. Nguyen, et. al., Phys. Rev. X 9, 041041 (2019).
[2] K. N. Nesterov, et. al., Phys. Rev. A 98, 030301 (2018).
[3] Q. Ficheux, et.al., arXiv:2011.02634 (2020).
[4] J. M. Chow, et. al., Phys. Rev. Lett. 107, 080502 (2011).
[5] S. Poletto, et. al., Phys. Rev. Lett. 109, 240505 (2012).

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Presenters

  • Konstantin Nesterov

    University of Wisconsin-Madison, University of Wisconsin - Madison, University of Wisconsin - Madison, Madison, University of Wisconsin, Madison

Authors

  • Konstantin Nesterov

    University of Wisconsin-Madison, University of Wisconsin - Madison, University of Wisconsin - Madison, Madison, University of Wisconsin, Madison

  • Quentin Ficheux

    University of Maryland, College Park, University of Maryland, Ecole Normale Superieure de Lyon, Univ Lyon, ENS de Lyon, Univ Claude Bernard, CNRS, Laboratoire de Physique,F-69342 Lyon,France

  • Chen Wang

    University of Massachusetts Amherst, University of Massachusetts - Amherst, Physics, University of Massachusetts Amherst

  • Vladimir Manucharyan

    University of Maryland, College Park, Department of Physics, University of Maryland, University of Maryland

  • Maxim G Vavilov

    University of Wisconsin-Madison, Department of Physics and Wisconsin Quantum Institute, University of Wisconsin - Madison, University of Wisconsin - Madison, University of Wisconsin - Madison, Madison, Department of Physics, University of Wisconsin-Madison, University of Wisconsin, Madison