Frankfurt 2006 – wissenschaftliches Programm

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A: Atomphysik

A 9: Poster I: Ultrakalte Atome und BEC

A 9.9: Poster

Dienstag, 14. März 2006, 16:30–18:30, Labsaal

Transition from a BEC to a Tonks-Girardeau Gas: An Exact Diagonalization Study — •Frank Deuretzbacher¹, Kai Bongs², Klaus Sengstock², and Daniela Pfannkuche¹ — ¹I. Institut für Theoretische Physik, Universität Hamburg, Jungiusstr. 9, 20355 Hamburg, Germany — ²Institut für Laserphysik, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany

We study ground state properties of a quasi 1D system consisting of spinless bosons which are confined in a harmonic trap and interact via a repulsive delta potential. Using the exact diagonalization method we analyze various quantities in the weak, intermediate and strong coupling regime. In particular the kinetic and interaction energy show a rich, unexpected behavior which cannot be explained within a mean-field approximation. Correlation effects - induced by the repulsive, short ranged force - start to dominate the system at rather low coupling strengths. It is known that the bosons behave very similar to non-interacting fermions in the strong coupling regime. We show the evolution from a BEC-like density to a density of non-interacting fermions. However, other quantities like the momentum distribution or the mean occupation of the oscillator eigenfunctions do not show fermionic behavior.