Title:Demonstrating beam splitters for reaction pathways in the field of cold chemistry

Speaker:Johannes Hecker Denschlag, Institut für Quantenmaterie, Universität Ulm

Time:10:00am, 2024-11-06 

Venue:Room C302,  New Science Building

Abstract:Our group studies chemical reactions of ultracold Rb atoms in a state-to-state resolved fashion, where we prepare reactants in well defined quantum states and measure the quantum states of the molecular products. In particular, we focus on three-body recombination where three atoms collide, forming a diatomic molecule. The third atom carries away part of the binding energy. We are currently investigating methods to gain control over this chemical reaction. By making use of either a magnetically tunable Feshbach resonance or an avoided crossing of molecular levels we can effectively construct different kinds of beam splitters for the reaction pathways. The idea is to resonantly admix at specific points of the reaction coordinate additional quantum states to the original collision complex. This opens up an additional pathway that the reaction can take. By tuning the magnetic field in our experiments, we can control these beam splitters and can redirect a sizeable fraction of the reaction flux between different product channels. These beam splitters are fully coherent and, in the future, it should be possible to use them also in interferometric schemes for controlling the reaction.

Bio:Professor Johannes Hecker Denschlag obtained his Ph.D. at the Institute for Experimental Physics from University of Innsbruck. He worked as a Associate Professor at University of Innsbruck in 2006-2009. He has been a professor and Head of the Institute of Quantum Matter at University of Ulm since 2009. He has been recognized with several honors, including the Rudolf-Kaiser-Preis (2007) and a Fellowship from the American Physical Society (APS) in 2018.