Stuttgart 2012 – scientific programme
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A: Fachverband Atomphysik
A 40: Poster: Ultra-cold atoms, ions and BEC
A 40.27: Poster
Thursday, March 15, 2012, 16:30–19:00, Poster.V
Non-linear and metastable dynamics of a Bose-Einstein condensate — •Holger Hauptmann1, Sigmund Heller1, Patrick Navez1, Holger Kantz2, and Walter Strunz1 — 1Technische Universität Dresden — 2Max-Planck-Institut für Physik komplexer Systeme, Dresden
We examine the non-linear dynamics associated to the lowest breathing mode of a self-interacting repulsive Bose-Einstein condensate at zero temperature with the Gross-Pitaevskii equation in a three-dimensional harmonic trap under external time-periodic stretching and squeezing. This perturbation leads to collective excitations of this many-body system und we observe a resonance-like behavior. To understand this phenomenon qualitatively, we derive an approximative system of equations, which resembles equations of motion for a classical particle in an electromagnetic field and external potential. This analogy allows us to identify the resonance as emerging from a saddle point.
Furthermore we investigate the metastability of the relative motion between a Bose-Einstein condensate und its thermal cloud at finite temperature in a harmonic trap. Stirring the system at low frequencies leads to a rotation of the thermal cloud with a resting condensate. We are looking for the critical angular velocity between condensate and thermal cloud for which the system becomes unstable.