We present a quantitative study of roughness in the magnitude of the magnetic field produced by a current carrying microwire, i.e. in the trapping potential for paramagnetic atoms. We show that this potential roughness arises from deviations in the wire current flow due to geometric fluctuations of the edges of the wire : a measurement of the potential using cold trapped atoms agrees with the potential computed from the measurement of the wire edge roughness by a scanning electron microscope.

We present the experimental realization of a pumped atom laser. We demonstrate the pumping through measurements of the source and laser-mode atom numbers, making a rate equation study of the pumping process.Comment: Version 2 contains 18 pages and 4 figures. We have significantly rewritten the introduction, as well as including a discussion of Rayleigh and Raman superradiant scattering and how these relate to continuous pumping of an atom laser. Five new references were adde

We present a detailed model describing the effects of wire corrugation on the trapping potential experienced by a cloud of atoms above a current carrying micro wire. We calculate the distortion of the current distribution due to corrugation and then derive the corresponding roughness in the magnetic field above the wire. Scaling laws are derived for the roughness as a function of height above a ribbon shaped wire. We also present experimental data on micro wire traps using cold atoms which complement some previously published measurements [11] and which demonstrate that wire corrugation can satisfactorily explain our observations of atom cloud fragmentation above electroplated gold wires. Finally, we present measurements of the corrugation of new wires fabricated by electron beam lithography and evaporation of gold. These wires appear to be substantially smoother than electroplated wires.PACS. 39.25.+k Atom manipulation (scanning probe microscopy, laser cooling, etc.) -03.75.Be Atom and neutron optics