%0 Generic
%A Wenz, Andre Niklas
%C Heidelberg, Deutschland
%D 2013
%F heidok:16025
%R 10.11588/heidok.00016025
%T From Few to Many: Ultracold Atoms in Reduced Dimensions
%U https://archiv.ub.uni-heidelberg.de/volltextserver/16025/
%X This thesis reports on experimental studies exploring few and many-body physics of ultracold  Bose and Fermi gases with reduced dimensionality. These experiments illustrate the versatility  and great amount of control over the particle number, the interaction and other degrees of  freedom, like the spin, that these generic quantum systems offer. In the first part of this  thesis, we use quasi one-dimensional few-particle systems of one to ten fermionic atoms to  investigate the crossover from few to many-body physics. This is achieved by measuring the  interaction energy between a single impurity atom in a state |down> which repulsively interacts  with an increasing number of majority atoms in a state  |up>. We find that the system quickly  approaches the results from the many-body theory, which describes the behavior of a single  impurity immersed in a Fermi sea of an infinite number of majority particles. The second  part of this thesis presents studies of the time evolution of a bosonic F=1 spinor BEC of 87Rb  atoms. In this system, we investigate the emergence and coarsening of ferromagnetic spin  textures from initially unmagnetized samples. While the ferromagnetic domains grow, we  observe the development of a spin space anisotropy which is in agreement with the predicted  phase-diagram. The last part of this thesis presents our first steps towards the investigation  of phase coherence of quasi two-dimensional quantum gases in the crossover from bosonic  molecules to fermionic atoms.