Reinforcement learning for optimization of fluxonium two-qubit gates

ORAL

Abstract

Among superconducting qubits, the fluxonium is a promising alternative to the transmon for gate-based quantum information processing. Here we will discuss our recent demonstration (arXiv:2304.06087) of an architecture for fluxonium-fluxonium two-qubit gates mediated by transmon couplers (FTF, for fluxonium-transmon-fluxonium). Relative to architectures that exclusively rely on a direct coupling between fluxonium qubits, FTF enables stronger couplings for gates using non-computational states while simultaneously suppressing the static controlled-phase entangling rate (ZZ) down to kHz levels, all without requiring strict parameter matching. We implemented FTF with a flux-tunable transmon coupler and demonstrated a microwave-activated controlled-Z (CZ) gate whose operation frequency could be tuned over a 2 GHz range, adding frequency allocation freedom for FTF in larger systems. To optimize this gate, we implemented model-free reinforcement learning of the pulse parameters to boost the mean gate fidelity up to 99.922±0.009%, averaged over roughly an hour between scheduled training runs. In this talk, we will discuss the details of this calibration procedure and opportunities for improvements.

* This research was supported by an appointment to the Intelligence Community Postdoctoral Research Fellowship Program at MIT, administered by Oak Ridge Institute for Science and Education through an interagency agreement between the U.S. Department of Energy and the Office of the Director of National Intelligence. This research is funded by the U.S. Army Research Office under Award No. W911NF-23-1-0045 and by the Under Secretary of Defense for Research and Engineering under Air Force Contract No. FA8702-15-D-0001. L.D. acknowledges support by an IBM PhD Fellowship. 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 U.S. Government.

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Publication: High-Fidelity, Frequency-Flexible Two-Qubit Fluxonium Gates with a Transmon Coupler

Presenters

  • Max Hays

    MIT, Massachusetts Institute of Technology (MIT), Massachusetts Institute of Technology MI, Massachusetts Institute of Technology, Massachussets Institute of Technology, Massachusetts Institute of Technology MIT

Authors

  • Max Hays

    MIT, Massachusetts Institute of Technology (MIT), Massachusetts Institute of Technology MI, Massachusetts Institute of Technology, Massachussets Institute of Technology, Massachusetts Institute of Technology MIT

  • Leon Ding

    Massachusetts Institute of Technology MI, Massachusetts Institute of Technology

  • Youngkyu Sung

    Massachusetts Institute of Technology, Massachusetts Institute of Technology MIT

  • Bharath Kannan

    Massachusetts Institute of Technology MI

  • Junyoung An

    Massachusetts Institute of Technology MI, Massachusetts Institute of Technology

  • Agustin Di Paolo

    MIT, Massachusetts Institute of Technology

  • Amir H Karamlou

    Massachusetts Institute of Technology MI

  • Thomas M Hazard

    Lincoln Laboratory, Massachusetts Institute of Technology, MIT Lincoln Lab, MIT Lincoln Laboratory

  • Kate Azar

    MIT Lincoln Laboratory, Wellesley Coll

  • David K Kim

    MIT Lincoln Lab, MIT Lincoln Laboratory

  • Bethany M Niedzielski

    MIT Lincoln Lab, MIT Lincoln Laboratory

  • Alexander Melville

    MIT Lincoln Laboratory

  • Mollie E Schwartz

    MIT Lincoln Laboratory

  • Jonilyn L Yoder

    MIT Lincoln Lab, MIT Lincoln Laboratory

  • Terry P Orlando

    Massachusetts Institute of Technology MIT, Massachusetts Institute of Technology

  • Simon Gustavsson

    Massachusetts Institute of Technology MIT, Massachusetts Institute of Technology

  • Jeffrey A Grover

    Massachusetts Institute of Technology, Massachusetts Institute of Technology (MIT), Massachusetts Institute of Technology MIT

  • Kyle Serniak

    MIT Lincoln Laboratory & MIT RLE, MIT Lincoln Laboratory, MIT Lincoln Laboratory, MIT RLE

  • William D Oliver

    Massachusetts Institute of Technology MI, Massachusetts Institute of Technology, Massachusetts Institute of Technology (MIT), Massachusetts Institute of Technology MIT