Quantifying Entanglement with a Joint Readout of Superconducting Qubits

ORAL

Abstract

We employ a single channel as a joint readout of highly-entangled two-qubit states in a circuit quantum electrodynamics architecture. The measurement model for the readout is fully characterized using a set of Rabi experiments demonstrating a large sensitivity to two-qubit correlations. We quantify the high degree of entanglement by measuring the violation of a Clauser-Horne-Shimony-Holt inequality with a value of $2.61\pm0.04$, without any optimization for the target state. In its present form, this joint readout will be capable of resolving improvements to the fidelity of two-qubit operations and will be extendable to systems of three or four qubits.

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Authors

  • Jerry Chow

    • Yale University

  • Leo DiCarlo

    • Yale University

  • Jay Gambetta

    • University of Waterloo
    • Institute for Quantum Computing
    • Institute of Quantum Computing, University of Waterloo
    • Institute for Quantum Computing and Department of Physics and Astronomy, University of Waterloo

  • Andreas Nunnenkamp

    • Yale University

  • Lev Bishop

    • Yale University

  • Luigi Frunzio

    • Yale University
    • Dept. of Applied Physics, Yale University

  • Michel H. Devoret

    • Yale Applied Physics
    • Yale University
    • Departments of Physics and Applied Physics, Yale University

  • S.M. Girvin

    • Yale University

  • Robert Schoelkopf

    • Yale University