A new preprint from our experiment has just been published:

Twin-atom beams
Robert Bücker, Julian Grond, Stephanie Manz, Tarik Berrada, Thomas Betz, Christian Koller, Ulrich Hohenester, Thorsten Schumm, Aurélien Perrin, Jörg Schmiedmayer
arXiv:1012.2348v1

We present highly efficient emission of twin-atom beams into a single transverse mode. As a source, we use a one-dimensional degenerate Bose gas in the first excited state of a tight waveguide potential. We observe the fluctuations in the population imbalance between the beams and find a suppression by one order of magnitude below the classical shot noise limit. The necessary excitation of the source is achieved by optimal control of the external wave function. Fundamental conservation laws ensure relaxation into the correlated modes, which is enhanced by bosonic amplification, analogous to an optical parametric oscillator for light.