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Tracking Non-Markovian Quantum Trajectories of a Superconducting Qubit from a Finite-Memory Bath

ORAL

Abstract

High-fidelity quantum control of superconducting qubits requires determining the time-dependent Hamiltonian of the applied control and environmental coupling. While continuous state tracking has proven effective for determining Markovian qubit time-evolution, coupling to non-computational subspaces or a finite-memory bath can result in non-Markovian dynamics. We use quantum state tracking with continuous weak measurement to experimentally investigate non-Markovianity in a transmon qubit strongly coupled to an unmonitored bath qubit via a cross-resonance interaction. We measure state decay and revival, a signature of non-Markovianity, and train a recurrent neural network to reconstruct quantum trajectories for dynamics that are difficult to describe with single-qubit trajectory theory.

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Presenters

  • Noah Stevenson

    Univ of California – Berkeley, University of California, Berkeley, Univ of California - Berkeley

Authors

  • Noah Stevenson

    Univ of California – Berkeley, University of California, Berkeley, Univ of California - Berkeley

  • Gerwin Koolstra

    Lawrence Berkeley National Laboratory, University of California, Berkeley

  • Karthik Siva

    University of California, Berkeley, Univ of California – Berkeley, Univ of California - Berkeley

  • Ravi K. Naik

    University of California, Berkeley, Univ of California – Berkeley, Physics, University of California, Berkeley, University of California Berkeley, Univ of California - Berkeley, Quantum Nanoelectronics Laboratory, Dept. of Physics, University of California, Berkeley, University of California - Berkeley

  • William Livingston

    University of California, Berkeley, Univ of California – Berkeley, Univ of California - Berkeley

  • Shiva Lotfallahzadeh Barzili

    Chapman Univ, Chapman University

  • Justin G. Dressel

    Chapman Univ, Chapman University

  • Irfan Siddiqi

    Lawrence Berkeley National Laboratory, University of California, Berkeley, Univ of California - Berkeley, Univ of California – Berkeley, Quantum Nanoelectronics Lab, UC Berkeley, Physics, University of California, Berkeley, Quantum Nanoelectronics Laboratory, Dept. of Physics, University of California, Berkeley