Abstract
We consider the simplest nonintegrable model of the multistate Landau-Zener transition. In this model, two pairs of levels in two tunnel-coupled quantum dots are swept past each other by the gate voltage. Although this model is nonintegrable, it can be solved analytically in the limit when the interlevel energy distance is much smaller than their tunnel splitting. The result is contrasted to the similar model, in which one of the dots contains only one level. The latter model does not allow interference of the virtual transition amplitudes, and it is exactly solvable. In the model, the probability for a particle, residing at time in one dot, to remain in the same dot at , falls off exponentially with tunnel coupling. By contrast, in the model, this probability grows rapidly with tunnel coupling. The physical origin of this growth is the formation of the tunneling-induced collective states in the system of two dots. This can be viewed as a manifestation of the Dicke effect.
- Received 4 August 2017
- Revised 5 September 2017
DOI:https://doi.org/10.1103/PhysRevB.96.115437
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