Collisions of cold ions and Bose?Einstein condensates

AJ Ard-Jan Moerdijk

David Alexander Anderson, Andrew T. Cadotte, Rachel Sapiro +1 more

T. Dieterle, Moritz Berngruber, Christian Hölzl +4 more

We investigate inelastic collision dynamics of a single cold ion in a Bose-Einstein condensate. We observe rapid ion-atom-atom three-body recombination leading to the formation of weakly bound molecular ions followed by secondary two-body molecule-atom collisions quenching the rovibrational states towards deeper binding energies. In contrast to previous studies exploiting hybrid ion traps, we work in an effectively field-free environment and generate a free low-energy ionic impurity directly from the atomic ensemble via Rydberg excitation and ionization. This allows us to implement an energy-resolved field-dissociation technique to trace the relaxation dynamics of the recombination products. Our observations are in good agreement with numerical simulations based on Langevin capture dynamics and provide a complementary means to study stability and reaction dynamics of ionic impurities in ultracold quantum gases.

Stefan Schmid, Arne Härter, Johannes Hecker Denschlag

We investigate the interaction of a laser-cooled trapped ion (Ba+ or Rb+) with an optically confined ⁸⁷Rb Bose-Einstein condensate. The system features interesting dynamics of the ion and the atom cloud as determined by their collisions and their motion in their respective traps. Elastic as well as inelastic processes are observed and their respective cross sections are determined. We demonstrate that a single ion can be used to probe the density profile of an ultracold atom cloud.

Fabio Lingua, Luca Lepori, F. Minardi +2 more