Darmstadt 2008 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 27: Poster Quantengase
Q 27.20: Poster
Tuesday, March 11, 2008, 16:30–19:00, Poster C2
Interaction-induced dephasing of Bloch oscillations - experiments and simulations — •Manfred Mark, Matthias Gustavsson, Elmar Haller, Johann Danzl, and Hanns-Christoph Nägerl — Institut für Experimentalphysik und Forschungszentrum für Quantenphysik, Universität Innsbruck, 6020 Innsbruck, Austria
A BEC in an optical lattice undergoes Bloch oscillations when subject to an external force. However, interactions lead to dephasing, limiting the number of oscillations one can observe.
We quantitatively characterize this dephasing by tuning the interaction strength using a Feshbach resonance. For non-zero interaction strength, structure on a scale much smaller than the Bloch momentum can be observed in the momentum distribution of a dephased condensate.
For vanishing interaction strength, we are able to follow more than 20000 oscillations over 12 s. Also a measurement of the Ramsauer-Townsend minimum with a precision of 10−5 was performed. In this regime breakdown and revival phenomena in the presence of an additional harmonic potential can be observed.
The performed measurements are compared to numerical simulations of discrete and non-discrete 1D Gross-Pitaevskii equations.