Darmstadt 2008 – wissenschaftliches Programm

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Q: Fachverband Quantenoptik und Photonik

Q 27: Poster Quantengase

Q 27.25: Poster

Dienstag, 11. März 2008, 16:30–19:00, Poster C2

Kicked Bose-Hubbard systems and kicked tops – destruction and stimulation of tunneling — •Martin P. Strzys, Eva-Maria Graefe, and Hans Jürgen Korsch — TU Kaiserslautern, Germany

In a two-mode approximation, Bose-Einstein condensates (BEC) in a double-well potential can be described by a many particle Hamiltonian of Bose-Hubbard type. We focus on such a BEC whose interatomic interaction strength is modulated periodically by δ-kicks which represents a realization of a kicked top. In the (classical) mean-field approximation it provides a rich mixed phase space dynamics with regular and chaotic regions. By increasing the kick-strength a bifurcation leads to the appearance of self-trapping states localized on regular islands. This self-trapping is also found for the many particle system, however in general suppressed by coherent many particle tunneling oscillations. By varying the kick-strength and the coupling between the two wells the quasi-energy levels undergo both avoided and even actual crossings. Therefore stimulation or complete destruction of tunneling can be observed for this many particle system. Thus real self-trapping is possible for the full quantum system and the system can be tuned from enforced tunneling to this regime. This yields the possibility of a systematic and accurate population transfer between the two potential wells.