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Q: Fachverband Quantenoptik und Photonik

Q 41: Quantengase: Dipolare Gase

Q 41.8: Talk

Thursday, March 5, 2009, 12:15–12:30, Audi-A

Classical and semiclassical dynamics of dipolar Bose-Einstein condensates — •Torsten Schwidder, Jörg Main, Holger Cartarius, and Günter Wunner — 1. Institut für Theoretische Physik, Universität Stuttgart, 70550 Stuttgart

Using a time-dependent Gaussian ansatz we convert the Gross-Pitaevskii equation for dipolar Bose-Einstein condensates into a two-dimensional nonintegrable Hamiltonian system. This opens the possibility to apply the powerful methods known from classical nonlinear dynamics to the motion of the condensate. We find periodic orbits of the classical system, describing periodic oscillations of the condensate, surrounded by quasi-periodic and chaotic trajectories. The stability of the periodic orbits is investigated in dependence of the physical parameters of the condensate and the existence of bifurcations is demonstrated.

Furthermore, we address the topic of macroscopic quantum tunnelling, which means a tunnelling from the metastable ground state of the condensate into collapse, in a semiclassical approach. The “bounce trajectory” is used to calculate the corresponding decay rates.