LATTRICS · Efimov trimers of ultracold cesium in optical lattices

Few-body physics with ultracold atoms has emerged as an exciting new research field, following experimental breakthroughs in the last few years. The universal behavior of few-body systems links areas of physics at vastly different energy scales, also bringing together scientific communities that are tradionally not connected. Efimov trimer states, very weakly bound quantum states of three particles, represent the paradigm of the field. The basic idea of the proposed project is to introduce tight external confinement into few-body physics with ultracold atoms, and to study Efimov trimers in situations of reduced dimensionality. This can be realized in one, two, or three dimensions using the powerful techniques of optical lattices. Such lattices are created in the standing-wave fields of different laser beams and represent a special expertise of the applicant. Ultracold ensembles cesium atoms near quantum-degeneracy, used by the host group for pioneering experiments on Efimov states, will serve as the model system. The project has three specific goals, which can be considered essential steps in few-body physics in systems with reduced dimensionality. First, a quasi-two-dimensional environment will be realized where the crossover from 3D to 2D will be studied. Second, Efimov trimers will be studied for systems of three atoms tighly confined to a single lattice site. Third, the new possibility to exploit three-body interactions to realize strongly correlated many-body systems in a three-dimensional lattice will be explored.