Phonon-Mediated Population Inversion in a Driven Double Quantum Dot

ORAL

Abstract

We examine phonon emission processes in a double quantum dot, configured as either a single or two-electron charge qubit and driven with resonant microwave excitation. Fast readout using a proximal rf quantum point contact (rf-QPC) enables charge sensing with high resolution and allows fine phonon-related features to be observed in microwave spectroscopy data. Spontaneous phonon emission is observed to produce level broadening and population inversion of a two-level system, a phenomena predicted theoretically but previously unreported. For the two-electron configuration, microwave transitions are shown to be spin-dependent, consistent with the well-understood mechanism of Pauli-blockade in double quantum dots.

*We acknowledge funding from IARPA, through ARO and the Australian Research Council CoE Scheme (Grant No. EQuS CE110001013).

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Authors

  • Xanthe Croot

    • 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

  • Andrew Doherty

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

  • Tom Stace

    • ARC Centre of Excellence for Engineered Quantum Systems, School of Mathematics and Physics, University of Queensland, Brisbane, QLD 4072, Australia.

  • Sean Barrett

    • Blackett Laboratory and Institute for Mathematical Sciences, Imperial College London, London SW7 2PG, United Kingdom

  • Hong Lu

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

  • Art Gossard

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

  • David Reilly

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