Hamburg 2009 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 11: Quantengase: Bosonen im Gitter II
Q 11.4: Talk
Monday, March 2, 2009, 17:15–17:30, VMP 6 HS-A
Quantitative measurement of the downshift of the critical temperature for Bose-Einstein condensation in an optical lattice — •Trotzky Stefan, Schnorrberger Ute, Thompson Jeff, and Bloch Immanuel — Universität Mainz
In the last years, experiments with ultracold quantum gases in optical lattices have developed in many directions, while various theoretical and numerical approaches have been proposed. The variety of Hamiltonians realizable in the experiments shows a large overlap with condensed matter systems. Therefore, the possibility to simulate large-scale quantum systems in the laboratory and to extract observables relevant for condensed matter physics provides a strong motivation for the work in this field. Full quantitative understanding of the usually inhomogeneous experimental systems, however, is extremely demanding for realistic system sizes.
Here, we present a quantitative measurement of the critical temperature Tc for Bose-Einstein condensation in a periodic potential and reveal the downshift of Tc upon approaching the critical interaction strenght for the transition from a superfluid to a Mott insulator. A direct comparison to ab initio quantum Monte-Carlo simulations for our trap parameters and particle numbers is used to verify the evaluation method. This comparison also enables us to check the adiabaticity of the loading process and to quantify non-adiabatic heating in the experimental system.