Ultracold rubidium molecules [Elektronische Ressource] / Thomas Volz

Technische Universit¨at Munc¨ henMax-Planck-Institut fur¨ QuantenoptikUltracold Rubidium MoleculesThomas VolzVollst¨andiger Abdruck der von der Fakult¨at fur¨ Physik der Techni-schen Universit¨at Munc¨ hen zur Erlangung des akademischen GradeseinesDoktors der Naturwissenschaften (Dr. rer. nat.)genehmigten Dissertation.Vorsitzender: Univ.-Prof. Dr. M. StutzmannPrufer¨ der Dissertation:1. Hon.-Prof. Dr. G. Rempe2. Univ.-Prof. Dr. H. FriedrichDieDissertationwurdeam13.03.2007beiderTechnischenUniversit¨atMunc¨ heneingereichtunddurchdieFakult¨atfur¨ Physikam11.04.2007angenommen.AbstractThis thesis describes experiments with diatomic molecules associated from ultra-87cold Rb atoms using magnetically-induced Feshbach resonances. The associa-tion method is based on a slow magnetic-field ramp across a Feshbach resonancewhich converts atom pairs into bound molecules. This constitutes a form of super-chemistry: The reaction is reversible and coherent. No latent heat is released, andasaconsequence, theFeshbachmoleculesareaboutascoldastheatomsfromwhichthey are associated.The first experiment introduced in this thesis, characterizes the broadest of the87known Feshbach resonances in Rb. To that end, the mean-field driven expansionof an atomic Bose-Einstein condensate near resonance is studied and the scatteringlength as a function of magnetic field is extracted. The position and magnetic-field width of the Feshbach resonance are determined to be 1007.