Direct Measurements of Collisional Dynamics in Ultracold Atom Triads
In this thesis, I present experimental methodology and results for direct measurements of ultracold few-atom collision dynamics, which allows quantum processes to be observed at the single event level. Three individual 85 Rb atoms are prepared in a specific quantum state and near-deterministically loaded into separate far-off resonance optical tweezers. The three trapping potentials are then merged, allowing the atoms to interact. By controlling the parameters of this interaction – duration and density of the atom triad – time-dependent atom loss from the trap due to two- and three-body inelastic collisions is observed. The loss rate from two-body collisions, K 2, is found to show a dependence on the trap beam intensity, which suggests that off-resonant photoassociative processes play a significant role in the system. In addition, the three-body recombination event rate constant, K 3 , is extracted from these loss measurements. The determination of K 3 in this manner marks a novel experimental measurement, as previous investigations have deduced the rate constant only by observing atom loss from a many-body sample. The measured few-body value for K3 shows consistency with its prediction from established theory illuminating a promising path for future experiments to take in the field of few-atom studies.
Advisor: Andersen, Mikkel
Degree Name: Master of Science
Degree Discipline: Physics
Publisher: University of Otago
Keywords: cold atoms; three atom; three body; recombination; three body recombination; ultracold; Rb; 85; Rb85; collisional dynamics; collisional; triad
Research Type: Thesis