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A: Atomphysik
A 18: Atom–/Ion–Oberflächen Wechselwirkungen
A 18.8: Vortrag
Donnerstag, 6. April 2000, 16:15–16:30, HS IV
Van der Waals Interactions of Cold Atoms with Hot Surfaces — •Alexander Chenet, Björn Hessmo, Eugen Hartungen, and Jörg Schmiedmayer — Institut für Experimentalphysik, Technikerstrasse 25, Universität Innsbruck, Austria
In recent Atom Optical experiments cold atoms are brought close to nanostructured surfaces. Two major effects are of interest: the Van der Waals interactions and the heating of cold atoms close to the warm surfaces. Here we present a study of Van der Waals interactions of cold atoms with
objects with a size which is in at least one dimension comparable to the range of the Van der Waals interaction. A possible experimental realization to measure the Van der Waals interaction of small objects is to study the interaction of an electrically charged wire and to study the decay of the atomic cloud close to this wire. Within the electric field of a charged wire (Vint=−2α q2/r2, with α the polarizability of the atoms, q the charge per length and r the distance atom-wire) there exist no stable orbits and the atoms either fall onto the wire and get absorbed or escape, depending on their velocity. When q=0 one is left with two effects, the geometrical size of the wire and the Van der Waals attraction between the atoms and the wire which increases the apparent size of the wire. To study the heating of the cold atoms close to hot surfaces, the atoms can be brought and magnetically held close to the surface of an atom chip which is discussed elsewhere. This work has been supported by the FWF Project 13369.