Seminar
Tuesday, 08 June, 2010
Group Seminar MPQ: Exploring Exotic Quantum Matter in Innsbruck: Ultracold Erbium Atoms and Efimov States
Tuesday, 8.06.2010 10 a.m. (s.t.) in Herbert-Walther-lecture room, MPQ Garching
Dr. Francesca Ferlaino, Institut für Experimentalphysik, Universität Innsbruck, Austria
In the first part of the talk, I will present the newborn experiment in Innsbruck operating with erbium atoms. Over the last years, the frontiers of ultracold quantum gases have been enlarged to new non-alkali atomic species, opening up intriguing possibilities for a variety of new applications. Erbium is a very interesting species, being an extremely heavy (166 a. u.) and strongly magnetic (7 \mu_B) rare-earth atom with a rich isotopic variety and a complex energy level structure. The unique combination of interesting properties allows studies of dipolar effects where the anisotropic and long-range dipole-dipole interactions dominating over the simple isotropic contact interaction. With erbium Feshbach molecules a more extreme situation can be achieved where the strength of the dipole-dipole interaction even gets close to the one between ground-state polar molecules.
In the second part of the talk, I will present our latest results on Efimov physics, obtained in an experiment operating with cesium atoms and molecules. I will first give an overview of the previous observations in this system for purely atomic samples, atom-dimer mixtures, and pure dimer samples. I will then report on a fundamental step beyond the Efimov scenario by investigating universal four-body processes. Our findings provide a strong evidence for the existence of a pair of four-body states, which is strictly connected to Efimov trimers via universal relations.