Hamburg 2009 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 41: Quantengase: Dipolare Gase

Q 41.2: Talk

Thursday, March 5, 2009, 10:45–11:00, Audi-A

Roton instability in dipolar Bose-Einstein condensates in an 1D optical lattice — •Michael Klawunn and Luis Santos — Institut für Theoretische Physik, Leibniz Universität Hannover, Appelstr. 2,D-30167 Hannover, Germany

The non-local nonlinearity introduced by Dipole-Dipole interaction plays a crucial role in the physics of dipolar Bose-Einstein condensates. In a sufficiently strong one-dimensional periodic potential we have a stack of strongly confined pancake condensates, which shows under certain conditions a roton minimum in the dispersion law of collective excitations. We have analyzed these roton-instabilities for the cases of transversal excitations of a straight vortex-line created in the direction of the optical lattice [1,2] or homogeneous in-plane excitations in all layers.

[1] M. Klawunn, R. Nath, P. Pedri, L. Santos, Phys. Rev. Lett. 100, 240403 (2008); [2] M. Klawunn, L. Santos, submitted to New J. Phys.