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Q: Quantenoptik und Photonik

Q 49: Quantengase V

Q 49.4: Vortrag

Mittwoch, 15. März 2006, 15:45–16:00, HVI

Dynamics and coherent control of a nonlinear three-level quantum system: Nonlinear eigenstates, Landau-Zener models and STIRAP — •Eva-Maria Graefe, Dirk Witthaut, and Hans-Jürgen Korsch — Technische Universität Kaiserslautern, Fachbereich Physik, Erwin-Schroedingerstr., D-67653 Kaiserslautern

We investigate the eigenstates and the dynamics of a Bose-Einstein condensate (BEC) in a triple-well trap in a three-level mean-field approximation. New nonlinear eigenstates emerge and disappear when the parameters are varied. This can lead to a breakdown of adiabaticity. The dynamical implications of this loss of adiabaticity are analyzed for various Landau-Zener-type models. We study the resulting novel crossing scenarios such as (self-intersecting) loops and beak-to-beak crossings, the corresponding catastrophe sets and the effects on the nonlinear Zener tunneling probability. Furthermore we generalize the STIRAP scheme for adiabatic coherent population transfer between atomic states to the nonlinear case. It is shown that STIRAP breaks down if the nonlinearity exceeds the detuning.