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A: Fachverband Atomphysik

A 24: Ultra-Cold Atoms, Ions and BEC II (with Q)

A 24.5: Talk

Thursday, March 5, 2009, 11:45–12:00, VMP 6 HS-C

Ultracold Atoms in Superconducting Microtraps — •Helge Hattermann, Daniel Cano, Brian Kasch, Florian Jessen, Max Kahmann, Dieter Kölle, Reinhold Kleiner, Claus Zimmermann, and József Fortágh — Center for Collective Quantum Phenomena and their Applications, Universität Tübingen, Auf der Morgenstelle 14, D-72076 Tübingen

We present recent measurements on ultracold atoms in a superconducting magnetic mictrotrap. It is shown that the Meissner effect plays a critical role in determining the near field trap shape. Our experimental setup consists of a ⁸⁷Rb BEC apparatus and an optical tweezers for transporting an ultracold atom cloud 44mm to the surface of a helium flow cryostat at 4 K. Here, the atoms are loaded into a magnetic microtrap formed by a 125 micron diameter superconducting niobium wire. The influence of the Meissner effect on the trap geometry has been evaluated both theoretically [1] and experimentally [2]. The Meissner effect shortens the distance between the trap and the superconductor, reduces the magnetic field gradients and lowers the trap depth. We also observed a temperature dependence of the magnetic field exclusion from the superconducting wire. Based on our measurements, we discuss future strategies for the manipulation of ultracold atoms in superconducting traps.

[1] D. Cano et al., Phys. Rev. A 77, 063408 (2008)

[2] D. Cano et al., Phys. Rev. Lett. 101, 183006 (2008)