The vortex nucleation and the emergence of quantum turbulence induced by oscillating magnetic fields, introduced by [1,2], left a few open questions concerning the basic mechanisms causing those interesting phenomema. Here, we report the experimental observation of the slosh dynamics of a magnetically trapped 87 Rb Bose-Einstein condensate (BEC) under the influence of a time-varying magnetic field. We observed a clear relative displacement in between the condensed and the thermal fraction center-of-mass. We have identified this relative counter move as an out-of-phase oscillation mode, which is able to produce ripples on the condensed/thermal fractions interface. The out-ofphase mode provides good evidences of a mechanism involved in the vortex nucleation and evolution when excited by time dependent magnetic fields.

We present a compact and versatile experimental system for producing Bose-Bose superfluid mixtures composed of sodium and potassium atoms. The compact design combines the necessary ultra-high vacuum enviroment for ultracold atom experiments with efficient atomic fluxes by using two-dimensional magneto-optical traps as independent source of atoms. We demonstrate the performance of this new machine by producing a Bose-Einstein condensate of 23 Na with ∼ 1 × 10 6 atoms. The tunability of Na-K bosonic mixtures is particularly interesting for studies regarding the nucleation of vortices and quantum turbulence. In this direction, the large optical access of the science chamber along the vertical direction provides the conditions to implement high resolution optical setups for imaging and rotating the condensate with a stirring beam. We show the nucleation of a vortex lattice with up to 14 vortices in the 23 Na BEC, attesting the efficiency of the experimental apparatus in studying the dynamics of vortices. * patricia.castilho@usp.br; Current address: Laboratoire Kastler Brossel, Collège

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The atom source is a relevant component in many atomic molecular optics experiments. The compactness and efficiency of the source are fundamental issues, acquiring more importance as the complexity of the experiments increases. Characterizing new techniques to produce high atom flux is necessary to know the efficiency and peculiarities of each one. This allows choosing the most suitable source for a specific experiment. In this work, we show a direct comparison between a two-dimensional magneto-optical trap (2D-MOT) and a Zeeman slower (ZS) as source of cold sodium atoms to load a standard three-dimensional magneto-optical trap. The optimum parameters for each case are obtained by observing the loading rate and the final number of atoms in the 3D-MOT. We conclude that the 2D-MOT provides a high flux of atoms comparable with that produced by the ZS, but with an enormous advantage with respect to the size of the apparatus.