Quantum-degenerate dipolar gases of bialkali molecules

At very low temperatures, matter enters a new regime where its properties are fully quantum-mechanical. Such quantum matter is very precisely controllable and offers many new properties that are likely to form the basis of future technologies. The EuroQUAM Programme is a EUROCORES Programme coordinated by the European Science Foundation to develop European research in Cold Quantum Matter. This proposal is part of the QuDipMol Collaborative Research Proposal, which brings together five experimental groups (Innsbruck, Freiburg, Firenze/Pisa, Durham and Hannover) and four theory groups (Durham, Orsay, Prague, Innsbruck). QuDipMol aims to form a quantum gas of polar (heteronuclear) alkali metal dimers. The molecules will be formed in traps containing mixed ultracold gases of two different alkali metal atoms, both by photoassociation and magnetic tuning through Feshbach resonances. Methods will be developed to increase the rate of formation and the density of the polar molecules. The Durham experimental group will work to create polar molecules using ultracold atomic gases of rubidium and caesium. This mixture is particularly attractive due to the unique nature of the interatomic collisions for these species, which should provide a means to manipulate the properties of the atomic mixture in order to make the molecule production more favourable.A major problem along the way is that the molecules may be destroyed (or lost from the trap) because of collisions with atoms or other molecules. It is important to understand these collisions, both to work around them during the formation of the molecules and to control the resulting polar quantum gas. The Durham theory group will work to achieve the necessary understanding by developing potential energy surfaces for the systems of interest and carrying out quantum-mechanical reactive scattering calculations.