Design of fluxonium coupling and readout via SQUID couplers

ORAL

Abstract

The superconducting fluxonium qubit has emerged as a promising alternative to the widely-studied transmon qubit due to increased coherence times at the half-flux quantum sweet-spot, large anharmonicity, and robust charge-noise insensitivity. Scaling to multi-qubit fluxonium systems requires implementation of fast, high-fidelity, and highly expressive quantum gates, with small residual coupling when the gate is off. In this work, we present the design of a 2D tunable coupler composed of a floating SQUID element achieving these requirements. We study the family of gates realizable with the phase coupling realized by the SQUID, and investigate their limits with regard to gate time, leakage, and drive-induced decoherence. We also study the element’s suitability for fast, high-fidelity readout for highly detuned fluxonium qubits retaining decoherence protection at half-flux quantum.

* Research was sponsored by the Army Research Office and was accomplished under Grant Number W911NF-23-1-0323. The views and conclusions contained in this document are those of the authors and should not be interpreted as representing the official policies, either expressed or implied, of the Army Research Office or the U.S. Government.

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Presenters

  • Noah J Stevenson

    University of California, Berkeley

Authors

  • Noah J Stevenson

    University of California, Berkeley

  • Zahra Pedramrazi

    Lawrence Berkeley National Laboratory

  • Noah Goss

    University of California Berkeley, University of California, Berkeley

  • Abhishek Chakraborty

    Chapman University, University of Rochester

  • Bibek Bhandari

    Institute for Quantum Studies, Chapman University, Chapman University

  • Daniel D Briseno-Colunga

    Chapman University

  • Chuan-Hong Liu

    University of California, Berkeley, University of Wisconsin - Madison, University of California Berkeley

  • Andrew N Jordan

    Chapman University

  • Justin G Dressel

    Chapman Univ, Chapman University

  • David I Santiago

    Lawrence Berkeley National Laboratory

  • Irfan Siddiqi

    University of California, Berkeley