Mainz 2017 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 6: Quantum Gases: Bosons I
Q 6.4: Vortrag
Montag, 6. März 2017, 15:15–15:30, P 204
Driven Bose-Hubbard Model with a Parametrically Modulated Harmonic Trap — Niklas Mann1, •M. Reza Bakhtiari1, Francesco Massel2, Axel Pelster3, and Michael Thorwart1,4 — 1I. Institut für Theoretische Physik, Universität Hamburg, Germany — 2Department of Physics and Nanoscience Center, University of Jyväkylä, Finland — 3Fachbereich Physik und Forschungszentrum OPTIMAS, Technische Universität Kaiserslautern, Germany — 4The Hamburg Centre for Ultrafast Imaging, Germany
We investigate a periodically driven one-dimensional Bose-Hubbard model, where the global harmonic trap is parametrically modulated. The delicate interplay of both the local atom interaction and the global driving allows to control the dynamical stability of the trapped quantum many-body state. This mechanism is illustrated for weak atom interaction by solving the discretized version of the Gross-Pitaevskii equation within a Gaussian variational ansatz, yielding to a Mathieu equation for the condensate width. With this it turns out that the parametric resonance condition can be tuned with the atom interaction strength. For stronger interactions, this mechanism is confirmed by applying the numerically exact time-evolving block decimation scheme. Furthermore, we show that the global periodic modulation induces for large enough driving frequencies an effective time-independent local hopping strength for the atom gas.