Lindblad Tomography of a Superconducting Quantum Processor

ORAL

Abstract

As progress is made towards the first generation of error-corrected quantum computers, careful characterization of a processor's noise environment will be crucial to designing tailored, low-overhead error correction protocols. While standard coherence metrics and characterization protocols such as T1 and T2, process tomography, and randomized benchmarking are now ubiquitous, these techniques provide only partial information about the dynamic multi-qubit loss channels responsible for processor errors, which can be described more fully by a Lindblad operator in the master equation formalism. In this talk, we outline and present the first experimental demonstration of Lindblad Tomography, a hardware-agnostic characterization protocol for tomographically reconstructing the Hamiltonian and Lindblad operators of a quantum channel from an ensemble of time-domain measurements. Performing Lindblad Tomography on a small superconducting quantum processor, we show that this technique characterizes and accounts for state-preparation and measurement (SPAM) errors and allows one to place strong bounds on the degree of non-Markovianity in the channels of interest. Comparing the results of single- and two-qubit measurements on a superconducting quantum processor, we demonstrate that Lindblad Tomography can also be used to identify and quantify sources of crosstalk on quantum processors, such as the presence of always-on qubit-qubit interactions.

*This research was funded in part by the U.S. Army Research Office Grant W911NF-18-1-0411 and by the Under Secretary of Defense for Research and Engineering under Air Force Contract No. FA8702-15-D-0001. The views and conclusions contained herein are those of the authors and should not be interpreted as necessarily representing the official policies or endorsements, either expressed or implied, of the US Government.

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Publication: arXiv:2105.02338 [quant-ph]

Presenters

  • Gabriel O Samach

    • Massachusetts Institute of Technology MIT
    • MIT

Authors

  • Gabriel O Samach

    • Massachusetts Institute of Technology MIT
    • MIT

  • Amy Greene

    • Massachusetts Institute of Technology MI
    • Massachusetts Institute of Technology MIT

  • Johannes Borregaard

    • Delft University of Technology

  • Matthias Christandl

    • University of Copenhagen

  • David K Kim

    • MIT Lincoln Lab
    • MIT Lincoln Laboratory

  • Christopher McNally

    • Massachusetts Institute of Technology MIT

  • Alexander Melville

    • MIT Lincoln Laboratory
    • MIT Lincoln Lab

  • Bethany M Niedzielski

    • MIT Lincoln Lab
    • MIT Lincoln Laboratory

  • Youngkyu Sung

    • Massachusetts Institute of Technology MIT

  • Danna Rosenberg

    • Massachusetts Institute of Technology MIT

  • Mollie E Schwartz

    • MIT Lincoln Lab
    • MIT Lincoln Laboratory

  • Jonilyn L Yoder

    • MIT Lincoln Lab
    • MIT Lincoln Laboratory

  • Terry P Orlando

    • Massachusetts Institute of Technology MIT

  • Joel I Wang

    • Massachusetts Institute of Technology MIT
    • Massachusetts Institute of Technology MI

  • Simon Gustavsson

    • Massachusetts Institute of Technology MIT
    • Massachusetts Institute of Technology

  • Morten Kjaergaard

    • Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, Copenhagen Denmark.
    • University of Copenhagen

  • William D Oliver

    • Massachusetts Institute of Technology MIT
    • Massachusetts Institute of Technology Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology Research Laboratory of Electronics
    • MIT Lincoln Laboratory and Department of Electrical Engineering & Computer Science and Department of Physics, Massachusetts Institute of Technology