Observation of Kinematic Reversibility in Magneto-optically Trapped Atom Clouds

With the ever increasing importance of the magneto-optical trap (MOT) in experimental atomic physics, it has become necessary to work toward a more comprehensive understanding of the nonlinear behavior of trapped atoms, which limits the quality and size of MOTs. In an effort to further our understanding of these nonlinearities, we have developed a fluid model of the trapped atom clouds and endeavor to study the similarities between the behavior of the atoms in the MOT and low Reynolds number fluids. A key feature of low Reynolds number fluids is that they exhibit kinematic reversibility: a phenomenon that occurs when, independent of time, a system acted on by a force returns to it's original state when those forces are applied reciprocally. We report on the first experimental observation of kinematic reversibility of a magneto-optically trapped atomic cloud. We highlight how reversibility in the MOT is, in general, very robust and discuss the cases under which the reversibility fails.