Abstract
Fermionic ytterbium as an alkaline-earth-like atom features a metastable "clock" state, which opens up the possibility of exploring interacting two-orbital many-body systems. The resulting strong interorbital spin-exchange interaction of ytterbium-173 leads to nuclear spin coupling dynamics between the orbitals, as well as to a novel type of Feshbach resonance due to the orbital and nuclear spin degree of freedom. This recently observed orbital Feshbach resonance allows to tune the interaction strength in an external magnetic field. In our experiment, we probe the effect of reduced dimensions using optical lattices in conjunction with the strongly interacting two-orbital gas, to explore the many-body physics of this Fermi gas using high-resolution spectroscopy, and to control the interaction of the orbital degree of freedom in this system.