Ultracold bosons in the flat band of an optical kagome lattice*

The kagome lattice hosts a flat band resulting from extensive geometric frustration. For fermions, this makes the kagome antiferromagnet a candidate for studying the quantum spin liquid phase. But even for weakly interacting scalar bosons, the many-body physics in a flat band is complex and not fully understood. Stable loading of ultracold atoms into the flat band of an optical kagome is challenging, as it is not the ground band. For the first time, we load bosonic ³⁹K atoms into the flat band of the kagome lattice using a negative absolute temperature scheme. I will report on recent progress in identifying the many-body physics that comes into play as we melt a kagome Mott insulator into the flat band.