Studying magnetism with cold atoms

J. Wu, Frank A. Moscatelli, E. Oh

We present a novel configuration of a magneto-optical trap for cold atoms. The trap is very simple in design, employing only a small permanent magnet and an external Helmholtz bias coil. The trap's principal advantage is that the entire volume of the overlapping laser beams can be used for atom guiding and manipulation. An especially interesting effect is the rotation of the trapped atoms in circular motion as the permanent magnet is rotated. Clouds containing on the order of 2*10(6) atoms are rotated up to 60Hz forming a 5 mm diameter ring. This rotation can potentially be used in studying the behavior of cold atoms in 2-dimensional potential as well as applications for rotational sensors. We also present a classical theoretical model to simulate the experiment.

A. Kasper, Sophie Schneider, Ch. vom Hagen +7 more

We describe an experiment to create a sizable 87 Rb Bose–Einstein condensate (BEC) in a simple magnetic microtrap, created by a current through a Z-shaped wire and a homogeneous bias field. The BEC is created close to a reflecting surface. It is an ideal coherent source for experiments with cold atoms close to surfaces, be it small-volume microtraps or directly studying the interactions between cold atoms and a warm surface.

B. Laburthe-Tolra

Edward A. Hinds, Ifan G. Hughes

For the last decade it has been possible to cool atoms to microkelvin temperatures (~1 cm s -1 ) using a variety of optical techniques. Light beams provide the very strong frictional forces required to slow atoms from room temperature (~500 m s -1 ). However, once the atoms are cold, the relatively weak conservative forces of static electric and magnetic fields play an important role. In our group we have been studying the interaction of cold rubidium atoms with periodically magnetized data storage media. Here we review the underlying principles of the forces acting on atoms above a suitably magnetized substrate or near current-carrying wires. We also summarize the status of experiments. These structures can be used as smooth or corrugated reflectors for controlling the trajectories of cold atoms. Alternatively, they may be used to confine atoms to a plane, a line, or a dot and in some cases to reach the quantum limit of confinement. Atoms levitated above a magnetized surface can be guided electrostatically by wires deposited on the surface. The flow and interaction of atoms in such a structure may form the basis of a new technology, `integrated atom optics' which might ultimately be capable of realizing a quantum computer.