Raman phonon emission in a driven double quantum dot.
The compound semiconductor gallium-arsenide (GaAs) provides an ultra-clean platform for storing and manipulating quantum information, encoded in the charge or spin states of electrons confined in nanostructures. The absence of inversion symmetry in the zinc-blende crystal structure of GaAs however, results in a strong piezoelectric interaction between lattice acoustic phonons and qubit states with an electric dipole, a potential source of decoherence during charge-sensitive operations. Here we report phonon generation in a GaAs double quantum dot, configured as a single- or two-electron charge qubit, and driven by the application of microwaves via surface gates. In a process that is a microwave analogue of the Raman effect, phonon emission produces population inversion of the two-level system and leads to rapid decoherence of the qubit when the microwave energy exceeds the level splitting. Comparing data with a theoretical model suggests that phonon emission is a sensitive function of the device geometry.
1] ARC Centre of Excellence for Engineered Quantum Systems, School of Physics, The University of Sydney, Sydney, New South Wales 2006, Australia [2].
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Colless
1] ARC Centre of Excellence for Engineered Quantum Systems, School of Physics, The University of Sydney, Sydney, New South Wales 2006, Australia [2].
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XG
Croot
ARC Centre of Excellence for Engineered Quantum Systems, School of Mathematics and Physics, University of Queensland, Brisbane, Queensland 4072, Australia.
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Stace
ARC Centre of Excellence for Engineered Quantum Systems, School of Physics, The University of Sydney, Sydney, New South Wales 2006, Australia.
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Doherty
Blackett Laboratory and Institute for Mathematical Sciences, Imperial College London, London SW7 2PG, UK.
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Barrett
Materials Department, University of California, Santa Barbara, California 93106, USA.
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Lu
Materials Department, University of California, Santa Barbara, California 93106, USA.
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AC
Gossard
ARC Centre of Excellence for Engineered Quantum Systems, School of Physics, The University of Sydney, Sydney, New South Wales 2006, Australia.
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Reilly