Darmstadt 2008 – wissenschaftliches Programm

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A: Fachverband Atomphysik

A 26: Posters: BECs, ultracold gases and plasmas

A 26.8: Poster

Donnerstag, 13. März 2008, 16:30–18:30, Poster C3

Bose-Einstein Condensates in Superconducting Microtraps — •Brian Kasch, Daniel Cano, Helge Hattermann, Reinhold Kleiner, Dieter Kölle, Claus Zimmermann, and József Fortágh — Physikalisches Institut, Universität Tübingen, Auf der Morgenstelle 14, D-72076 Tübingen

We present progress toward producing Bose-Einstein condensation in a superconducting magnetic microtrap. The scientific objective is the coupling of cold atoms to superconducting devices. An experimental system consisting of a BEC apparatus, and a Helium flow cryostat has been set up. A gas of Rb-87 atoms has been loaded into a magneto-optical trap. This cloud will be cooled by forced evaporation, and subsequently translated 5cm by means of optical tweezers to a magnetic microtrap generated on a niobium chip at 4,2 K.

We developed numerical methods for calculating magnetic fields in the vicinity of superconducting surfaces. Inhomogeneous current densities within the superconductor have been calculated using an energy-minimization procedure that relies on the London equations. Corresponding superconducting chips have been produced using optical lithography and lift-off techniques.

In a first experiment, we plan to measure the coherence time of a spin-polarized atomic cloud near a superconducting surface. Theoretical predictions show the spin-flip lifetime should be increased by several orders of magnitude as compared to the normal conducting state of the same wire. The current state of the experiment will be presented.