Continuous measurement of two spatially separated superconducting qubits: Quantum trajectories and feedback

ORAL

Abstract

Measurement can be harnessed to probabilistically generate entanglement in the absence of local interactions, for example between spatially separated quantum objects. Continuous weak measurement allows us to observe the dynamics associated with this process. In particular, we perform joint dispersive readout of two superconducting transmon qubits separated by one meter of coaxial cable. We track the evolution of a joint quantum state under the influence of measurement, both as an ensemble and as a set of individual quantum trajectories. We analyze the statistics of such quantum trajectories and find good agreement with a Bayesian formalism for a two-body quantum system. Such tracking opens the door to continuous feedback-stabilized remote entanglement.

*This work was supported by the Army Research Office and by the Fannie and John Hertz Foundation

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Authors

  • M.E. Schwartz

    • QNL, University of California, Berkeley

  • N. Roch

    • QNL, University of California, Berkeley

  • Felix Motzoi

    • Department of Chemistry, University of California, Berkeley
    • UC Berkeley

  • Birgitta Whaley

    • Department of Chemistry, University of California, Berkeley
    • Univeristy of California at Berkeley
    • UC Berkeley

  • Alexander N. Korotkov

    • Univ of California - Riverside
    • Department of Electrical Engineering, University of California, Riverside
    • UC Riverside, USA

  • Mohan Sarovar

    • Sandia National Laboratories, Livermore
    • Sandia National Laboratories

  • Irfan Siddiqi

    • QNL, University of California, Berkeley
    • University of California, Berkeley
    • QNL, UC Berkeley
    • Quantum Nanoelectronics Laboratory, Department of Physics, University of California, Berkeley