Coherence and chiral order in higher bands of an optical lattice
Prof. Dr. Andreas Hemmerich (Institut für Laserphysik, Universität Hamburg)

Atoms trapped in optical lattices have been used successfully to study many-body phenomena. But the shape that bosonic ground-state wavefunctions can take is limited, compromising the usefulness of this approach. Such limitations, however, do not apply to excited states of bosons. Atomic superfluids realized in higher-energy bands, where orbital degrees of freedom are essential, promise to provide insight into a wider range of many-body effects. I will discuss our observations of chiral order parameters in the P and F-bands, which break the lattice symmetry and time-reversal symmetry.