Lundi 01 octobre 2012 à 10h15
Salle 234, Ecole de Physique

Super fluid drag of two-species Bose-Einstein condensates in optical lattices

Patrick Hofer, University of Basel

Ultracold atomic gases in optical lattices constitute a tool for probing a variety of many-body phenomena such as the superfluid drag in two-component Bose-Einstein condensates (BECs). This non-dissipative drag effect, first studied by Andreev and Bashkin in the context of 3He-4He, couples the superflows of two interacting superfluids. We have derived an expression for the superfluid drag which holds for an arbitrary lattice geometry. Based on the numerically exact Bloch and Wannier functions we have quantified the drag for quasi two-dimensional lattice geometries, with focus on optical lattices created by three laser beams. Unlike previous findings, our results show a non-monotonic dependence on the lattice depth owing to the interplay between interaction and kinetic energy effects.