A collaboration between German and American scientists successfully measured chemical processes with an unparalleled resolution at the quantum level. For the first time, the scientists are able to determine the product state distribution across all quantum states immediately after the molecule formation. The research results deepen the understanding of ultracold chemical processes and can facilitate targeted reaction control at the quantum level. The scientific article of the researchers from the universities in Ulm and Hannover as well as the research institutions in the USA was published in the renowned journal 'Science'.
The researchers combined theory with experiment and focused on one of the most fundamental chemical reactions, the three-body recombination. In this process, three atoms react with each other to form a diatomic molecule and the third carries away a portion of the released energy. Hitherto, the exact states of the molecular end products were unknown. Now, however, the researchers around Professor Johannes Hecker Denschlag, Director of the Institute of Quantum Matter, are able to determine the molecular state in every detail right after the three-particle collision.
The experimental measurements took place at Ulm University: the gas of rubidium atoms is confined in a trap within an ultra-high vacuum apparatus, where a laser beam cools it to a temperature of a millionth of a degree Kelvin. This cold gas represents a very well defined starting condition at which the three-body recombination occurs. Based on the measured product distributions, the researchers were able to derive new rules for chemical reaction paths. 'Despite the supercomputer, the exact simulation of such reactions cannot be realised yet. Based on the identified reaction rules, however, the colleagues in the USA were able to develop a comparatively simple model with which some of the measurements from experiments can be explained,' elaborates Hecker Denschlag.
The results of the research team's experimental and theoretical works might be game-changing for the investigation of other ultracold chemical processes. 'In many laboratories the required infrastructure for such experiments is already in place, allowing other research groups to build on our work. The experimental results, in turn, challenge theorists to continuously refine their models and theories,' explains Denschlag. The new technique will help the understanding of increasingly complex chemical reactions, which might be utilised in the future to control the reaction process at the quantum level.
The researchers at Ulm University received funding from the German Research Foundation (DFG) and others to conduct their scientific work.
Background
Ulm University is one of the leaders in the field in quantum technology. In collaboration with scientists from the University of Stuttgart and Stuttgart's Max Planck Institute for Solid State Research, an interdisciplinary group of researchers at the Center (Eigenname!) for Integrated Quantum Science and Technology IQST strive to transfer findings of quantum research into technical application. The Collaborative Research Centre/Transregio21 'Control of Quantum Correlations in Tailored Matter' (Ulm, Stuttgart, Tübingen) and an ERC Synergy Grant worth € 10.3 million are further attest to Ulm's the exceptional research performance in quantum science. Ulm University was also invited to submit a full proposal in the field of quantum technology.