Spin drag below the condensation temperature of an ultra-cold Bose gas

Abstract

In this thesis, an experiment involving spin drag between two clouds of sodium atoms (one with spin -1, one with spin 0) in a Bose-Einstein condensate is described and analyzed in two different ways. These analysis methods involve both the movement of domain walls of the two clouds, and the movement of the centers of mass of the two clouds. It turns out that the movement of the domain walls is significantly different than that of the centers of mass of the clouds. Also, a couple of possible parameterizations are given to analyze the center of mass method properly. Furthermore, analytical formulas for the calculation of a magnetic cloverleaf trap (as used in the setup for Bose-Einstein condensation) are derived and the characteristics of this trap are discussed. The parameters describing the shape of the trap, which are the radial and axial trap frequencies, are calculated as a function of the current through the coils, and the change in magnetic field of the trap after applying several gradients is investigated. Finally, a series of experiments involving both the fast and slow flux of particles, used for loading the trap, from the oven to the vacuum chamber are described and analyzed. The results of the fast flux are compared with calculations involving the vapor pressure. The behavior of the magnetic field of the Zeeman coils is also discussed.