Düsseldorf 2007 – wissenschaftliches Programm

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A: Fachverband Atomphysik

A 27: Ultracold collisions (jointly with Q)

A 27.4: Vortrag

Freitag, 23. März 2007, 11:30–11:45, 6G

Magnetic noise in atom chips: impact of finite wire size — •Bo Zhang and Carsten Henkel — Institute fuer Physik, Universitaet Potsdam,Germany

We provide a detailed analysis of spin-flip transitions in atom chips, taking into account complex geometries. We focus on metallic wires of different shapes and cross-sections deposited on dielectric substrates. Our results show that the finite thickness and width of a metallic wire have an obvious impact on the atom trap lifetime. The spin orientation makes a big difference for magnetic noise above finite wires, in striking contrast to infinitely extended planar structures. Different interpolation formulas and approximations for magnetic field fluctuations in the near field of the wire are compared to exact numerical calculations. We work with surface integral equations and the boundary element method. Comparing to the surface impedance approximation familiar from microwave engineering, we find significant differences when the distance between the atom and the metallic surface is smaller than the skin depth.