Optimized Backgate Design for Enhancing Coherence Times in Graphene Gatemons

ORAL

Abstract

Gate-tunable Josephson junction-based qubits (gatemons) have emerged as a promising approach to mitigate some of the key challenges in standard, flux-tunable transmon superconducting qubits, such as qubit sensitivity to flux noise, crosstalk, and power dissipation. Unlike SQUIDs, gatemons do not rely on flux biases and can be controlled via an electrostatic gate. While gatemons have been realized in various systems, including semiconducting nanowires [1], two-dimensional electron gases [2], and graphene [3], their coherence times remain a limiting factor for achieving high-fidelity multi-qubit operations. Here, we present a graphene-based differential (floating) qubit design in which two capacitor pads are symmetrically coupled to the back gate line with equal strength. This geometry is expected to significantly inhibit energy decay through this channel, which is suspected to be the primary source of dissipation limiting prior work [3]. We explore these improvements in the context of device design, fabrication, and microwave measurements.

[1] Larsen et al. PRL (2015)

[2] Casparis et al. Nat. Nanotech. (2018)

[3] Wang*, Rodan-Legrain* et al. Nat. Nanotech. (2019)

* * This research was funded in part by the US Army Research Office grant no. W911NF-2210023, by the National Science Foundation QII-TAQS grant no. OMA-1936263, and by the Under Secretary of Defense for Research and Engineering under Air Force Contract No. FA8702-15-D-0001. D R-L acknowledges support from the Fundación Rafael del Pino. 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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Presenters

  • Daniel Rodan Legrain

    Massachusetts Institute of Technology - MIT

Authors

  • Daniel Rodan Legrain

    Massachusetts Institute of Technology - MIT

  • Joel I Wang

    Massachusetts Institute of Technology MI, Massachusetts Institute of Technology

  • Pablo M Mercader-Pérez

    Massachusetts Institute of Technology, MIT

  • Réouven Assouly

    Massachussets Institute of Technology

  • 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

  • Aranya Goswami

    Massachusetts Institute of Technology, MIT

  • Sameia Zaman

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

  • Beatriz S Yankelevich

    Massachusetts Institute of Technology, Rigetti Quantum Computing; Massachusetts Institute of Technology

  • Aziza Almanakly

    Massachusetts Institute of Technology

  • Thomas M Hazard

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

  • Michael A Gingras

    MIT Lincoln Laboratory

  • Bethany M Niedzielski

    MIT Lincoln Lab, MIT Lincoln Laboratory

  • Hannah M Stickler

    MIT Lincoln Laboratory

  • Mollie E Schwartz

    MIT Lincoln Laboratory

  • Jonilyn L Yoder

    MIT Lincoln Lab, MIT Lincoln Laboratory

  • Kenji Watanabe

    National Institute for Materials Science, NIMS, Research Center for Electronic and Optical Materials, National Institute for Materials Science, Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan, National Institute for Material Science

  • Takashi Taniguchi

    Kyoto Univ, National Institute for Materials Science, Research Center for Materials Nanoarchitectonics, Research Center for Materials Nanoarchitectonics, National Institute for Materials Science, National Institute for Materials Sciences, NIMS, International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan, National Institute for Material Science, International Center for Materials Nanoarchitectonics, NIMS, Japan, International Center for Materials Nanoarchitectonics, Tsukuba, National Institue for Materials Science, Kyoto University, National Institute of Materials Science, International Center for Materials Nanoarchitectonics and National Institute for Materials Science

  • 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

  • Pablo Jarillo-Herrero

    Massachusetts Institute of Technology MI, Massachusetts Institute of Technology MIT, Massachusetts Institute of Technology

  • William D Oliver

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