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All-electronic coherent population trapping in quantum dots

B. Michaelis·C. Emary·C. W. J. Beenakker
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Abstract

We present a fully electronic analogue of coherent population trapping in quantum optics, based on destructive interference of single-electron tunneling between three quantum dots. A large bias voltage plays the role of the laser illumination. The trapped state is a coherent superposition of the electronic charge in two of these quantum dots, so it is destabilized as a result of decoherence by coupling to external charges. The resulting current I through the device depends on the ratio of the decoherence rate Gamma_phi and the tunneling rates. For Gamma_phi --> 0 one has simply I=e Gamma_phi. With increasing Gamma_phi the current peaks at the inverse trapping time. The direct relation between I and Gamma_phi can serve as a means of measuring the coherence time of a charge qubit in a transport experiment.

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B. Michaelis, C. Emary, C. W. J. Beenakker. 2006-01-10. All-electronic coherent population trapping in quantum dots. https://doi.org/10.1209/epl%2Fi2005-10458-6

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