ISBN 9783843948814

978-3-8439-4881-4, Reihe Physik

Thomas Dieterle
A single, cold ion immersed in a Bose-Einstein condensate - Transport and inelastic collision dynamics

144 Seiten, Dissertation Universität Stuttgart (2021), Softcover, A5

Zusammenfassung / Abstract

This thesis studies the interaction of a single, cold Rubidium ion immersed in a Bose-Einstein condensate with neutral Rubidium atoms from the host gas. The single ion itself is generated from a precursor Rydberg atom incorporating a novel pulsed field ionization sequence to create the ionic impurity from the Rydberg atom. Strong Rydberg blockade guarantees the creation of a single impurity only. In particular, two main results are presented. First, transport dynamics of the ion through the Bose-Einstein condensate are investigated by applying small bias electric fields to guide the ion through the dense gas. Indications for diffusive transport are found and the mobility of the ion in the quantum gas is extracted and compared to numerical simulations based on sequential Langevin collisions.

Second, inelastic collision dynamics of the ion are studied. Rapid atom-atom-ion three-body recombination leading to the formation of weakly bound molecular ions followed by secondary molecule-atom quenching collisions is observed. The experimental conditions allow for the implementation of an energy-resolved field-dissociation technique to study the relaxation dynamics of the recombination products in detail. The results are compared to a numerical model based on pure Langevin capture dynamics and provide new means to examine the reaction dynamics of ionic impurities in ultracold quantum gases.