Dresden 2011 – wissenschaftliches Programm

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Q: Fachverband Quantenoptik und Photonik

Q 2: Quantum Gases: Bosons 1

Q 2.1: Vortrag

Montag, 14. März 2011, 10:30–10:45, HÜL 386

Two-point density correlations of quasicondensates in free expansion — •Stephanie Manz, Robert Bücker, Thomas Betz, Christian Koller, Igor Mazets, Aurelién Perrin, Thorsten Schumm, and Jörg Schmiedmayer — Atominstitut, TU Wien

We measure the two-point density correlation function of freely expanding quasicondensates in the weakly interacting quasi-one-dimensional (1D) regime. While initially suppressed in the trap, density fluctuations emerge gradually during expansion as a result of initial phase fluctuations present in the trapped quasicondensate. Asymptotically, they are governed by the thermal coherence length of the system. Our measurements take place in an intermediate regime where density correlations are related to near-field diffraction effects and anomalous correlations play an important role. Comparison with a recent theoretical approaches yields good agreement with our experimental results and shows that density correlations can be used for thermometry of quasicondensates. New results testing this method on samples with low atom numbers will be presented as well.