Ultracold thermal atoms and Bose-Einstein condensates interacting with a single carbon nanofiber [Elektronische Ressource] / vorgelegt von Philipp Schneeweiß

Ultracold Thermal Atoms andBose-Einstein Condensates Interactingwith a Single Carbon Nano berDissertationzur Erlangung des Grades eines Doktorsder Naturwissenschaftender Mathematisch-Naturwissenschaftlichen Fakult atder Eberhard Karls Universit at Tubingenvorgelegt vonPhilipp Schneeweiaus Potsdam2011.Tag der mundlic hen Prufung: 27. Januar 2011Dekan: Prof. Dr. Wolfgang Rosenstiel1. Berichterstatter: Prof. Dr. J ozsef Fort agh2. Berichr: Prof. Dr. Claus ZimmermannAbstractThe present thesis investigates the decay of ultracold atoms from a magnetic trap dueto the interaction with a single carbon nano ber. The latter is spatially overlappingwith the atomic cloud. For both an ultracold thermal cloud and a Bose-Einsteincondensate, the atomic loss has been measured for di erent interaction times anddegrees of cloud-nano ber overlap. Relevant theoretical concepts to analyze themeasurements are derived and applied to the experimental results. For the thermalas well as the degenerate gas case, the atom loss is signi cantly faster than expectedfrom the geometry of the nano ber. The experimental data is consistent with anenhanced atom loss due to an attractive Casimir-Polder force between the nano berand the ultracold atoms. Using a power-law approximation, the Casimir-Polderpotential of the nano ber is quantitatively obtained by tting the experimentaldata.