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.

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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