Hannover 2010 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 38: Quantum Gases: Bosons III / Lattices I
Q 38.1: Vortrag
Mittwoch, 10. März 2010, 16:30–16:45, E 001
Dipolar Bose-Einstein condensates: stability properties and physics in deep optical lattices. — •Kazimierz Łakomy1, Rejish Nath1,2, and Luis Santos1 — 1Institut für Theoretische Physik , Leibniz Universität, Hannover, Appelstrasse 2, D-30167, Hannover, Germany — 2Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Strasse 38, D-01187 Dresden, Germany
Due to their partially attractive character, dipole-dipole interactions may drive instability in dipolar gases. In this presentation we analyze in detail the instability of pancake-like condensates both against phonon- and the roton-instability as a function of the dipole strength and the strength of short-range interactions. After briefly reviewing the different types of instabilities in dipolar condensates, we show that the boundary between stability and roton instability presents a re-entrant shape, which allows for scenarios where the system is only stable for a window of dipole strengths, i.e. the system is photon- or roton-unstable for small and large dipole-strengths. We determine as well the universal critical short-range interaction below which the gas is always unstable. In the last part of the talk we shall discuss recent results on the properties of solitons in dipolar condensates in deep optical lattices.