Düsseldorf 2007 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

Q: Fachverband Quantenoptik und Photonik

Q 5: Quantengase (Bose-Einstein-Kondensation)

Q 5.1: Gruppenbericht

Montag, 19. März 2007, 14:00–14:30, 6J

Coherence in two dimensional Bose gases — •Peter Krüger, Zoran Hadzibabic, Marc Cheneau, Baptiste Battelier, Patrick Rath, and Jean Dalibard — Laboratoire Kastler Brossel, Ecole Normale Superieure, Paris, France

Dimensionality can drastically affect the properties of cold degenerate quantum gases. In three dimensions bosonic clouds can form Bose-Einstein condensates in which full phase coherence, i.e. true long range order, extends over the entire system. This is no longer true in reduced dimensions. Two dimensional systems are special as correlations in a quasi-ordered phase decay only algebraicly and not exponentially, so that order phenomena such as superfluidity can persist.

We implement a two dimensional bosonic system with Rb-87 atoms confined in a combined magnetic and optical potential and study coherence properties by a matter wave heterodyning technique. Interference experiments between two uncoupled flat clouds allow us to study phase correlations and the superfluid to normal phase crossover known as the Berizinskii Kosterlitz Thouless crossover.