Interplay between Photogenerated Charges and Microwave Losses in Quantum Dot Hybrid Systems

ORAL

Abstract

Quantum processing units (QPUs) based on quantum dots are currently limited in qubit scalability due to the inherent number of control gates and fabrication inconsistencies. Photogenerated charges trapped inside gate-defined quantum dots offer a promising platform for spin qubits, addressing those two limitations. However, this technique introduces new challenges, particularly in hybrid systems with superconducting coplanar waveguide resonators, where photogenerated charges can act as loss channels due to their uncontrolled creation throughout the semiconductor.

To address this, we combine two strategies to confine charge generation exclusively to the quantum dot region. First, the heterostructure is selectively etched away, leaving the active region only under the control gates. Second, a GRIN lens mounted on a piezo stack delivers light with 2-micron precision, ensuring targeted charge generation.

This talk will discuss the effectiveness of these techniques and their implications for future photopopulated quantum dot development.

*This research was partially funded by the Canada First Research Excellence Fund, the Government of Canada's Quantum Sensors Challenge program, and the Université de Sherbrooke Excellence Scholarship Program.

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Publication: Pierre Lefloic, Zhiren Wang and Michel Pioro-Ladrière. 2024. Method and system for preparing quantum dots for quantum computation. PCT Worldwide application Patent WO2024098134A1

Presenters

  • Pierre Lefloic

    • Université de Sherbrooke

Authors

  • Pierre Lefloic

    • Université de Sherbrooke

  • Steve Lamoureux

    • Université de Sherbrooke

  • Lucas Duhem

    • ENS Paris-Saclay

  • Yasmine Faraj

    • Université de Sherbrooke

  • Zhiren Wang

    • CEA-Saclay

  • Michel Pioro-Ladriere

    • Nord Quantique

  • Louis Gaudreau

    • Natl Res Council
    • National Research Council Canada

  • Alicia Kam

    • National Research Council Canada

  • Mathieu L Juan

    • Université de Sherbrooke
    • Universite de Sherbrooke