Dispersive Readout of a Few-Electron Double Quantum Dot with Fast rf Gate-Sensors

ORAL

Abstract

We report the dispersive charge-state readout of a double quantum dot in the few-electron regime using the $in$ $situ$ gate electrodes as sensitive detectors. We benchmark this gate-sensing technique against the well established quantum point contact (QPC) charge detector and find comparable performance with a bandwidth of $\sim$ 10 MHz and an equivalent charge sensitivity of $\sim$ 6.3 $\times$ $10^{-3}$ e/$\sqrt{\mathrm{Hz}}$. Dispersive gate-sensing alleviates the burden of separate charge detectors for quantum dot systems and promises to enable readout of qubits in scaled-up arrays.

*We acknowledge funding from the U.S. Intelligence Advanced Research Projects Activity (IARPA), through the U.S. Army Research Office and the Australian Research Council Centre of Excellence Scheme (Grant No. EQuS CE110001013)

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Authors

  • Alice Mahoney

    • ARC Centre of Excellence for Engineered Quantum Systems, School of Physics, The University of Sydney, Sydney, NSW 2006, Australia.

  • James Colless

    • ARC Centre of Excellence for Engineered Quantum Systems, School of Physics, The University of Sydney, Sydney, NSW 2006, Australia.

  • John Hornibrook

    • ARC Centre of Excellence for Engineered Quantum Systems, School of Physics, The University of Sydney, Sydney, NSW 2006, Australia.

  • Andrew Doherty

    • ARC Centre of Excellence for Engineered Quantum Systems, School of Physics, The University of Sydney, Sydney, NSW 2006, Australia.

  • David Reilly

    • ARC Centre of Excellence for Engineered Quantum Systems, School of Physics, The University of Sydney, Sydney, NSW 2006, Australia.

  • Hong Lu

    • Materials Department, University of California, Santa Barbara, California 93106, USA.

  • Art Gossard

    • Materials Department, University of California, Santa Barbara, California 93106, USA.