Hannover 2010 – scientific programme

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A: Fachverband Atomphysik

A 29: Atomic Systems in External Fields II

A 29.3: Talk

Friday, March 12, 2010, 14:30–14:45, B 302

Sub-Poissonian atom number fluctuations by three-body loss in mesoscopic ensembles — •Shannon Whitlock, Caspar Ockeloen, and Robert Spreeuw — Van der Waals-Zeeman Institute, University of Amsterdam, The Netherlands

We show that three-body loss of trapped atoms leads to sub-Poissonian atom number fluctuations. We prepare hundreds of dense ultracold ensembles in an array of magnetic microtraps on a permanent-magnet atom chip. We observe rapid losses due to three-body recombination. The resulting shot-to-shot fluctuations of the number of atoms per trap are sub-Poissonian, for ensembles comprising 50–300 atoms. The measured relative variance or Fano factor F=0.53± 0.22 agrees very well with the prediction by an analytic theory (F=3/5) and numerical calculations. Density dependent loss such as three-body recombination can thus be used to prepare small and well-defined numbers of atoms in each microtrap. These results will facilitate studies of quantum information science with mesoscopic ensembles.