Berlin 2005 – wissenschaftliches Programm

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Q: Quantenoptik und Photonik

Q 20: Poster Fallen & Kühlung

Q 20.10: Poster

Montag, 7. März 2005, 11:00–12:30, Poster HU

Atom Chips in the real World: The role of wire corrugation — •Thorsten Schumm, Jérôme Esteve, Jean-Baptiste Trebbia, Hai Nguyen, Isabelle Bouchoule, Chris Westbrook, and Alain Aspect — Laboratoire Charles Fabry de l’Institut d’Optique, UMR 8501 du CNRS, 91403 Orsay Cedex, France

Atom chips have proven to be a powerfull tool in atom optics. They combine robusteness, simplicity and low power consumption with strong confinement and high flexibility in the design of the trapping geometry. "Real world" limitations of this system are therefore of special interest: losses and heating of atoms close to room temperature metallic surfaces have been theoretically predicted and experimentally observed soon after the first realization of atom chips. An unpredicted phenomenon was the fragmentation of trapped cold atomic clouds or Bose condensates in magnetic microtraps. It has been shown, that this fragmentation is due to static distortions of the curent flow inside the wires, creating a coresponding roughness in the trapping potential. In our work, we present a quantitative analysis of the potential roughness created by micro wires. The trapping potential of a chip trap was probed using cold atoms. We analized the trapping wire and its geometrical edge and surface defects using SEM and AFM techniques. A theoretical model allows us to calculate the potential expected from such a wire. We find good aggreement between the potential rougness measured with atoms and the one calculated from the wire shape, explaining the fragmentation observed in our experimental system by geometrical wire deformations.