Towards ultracold atoms in a kagome optical lattice with single-site-resolved imaging*

We are building an ultracold-atom setup implementing an optical kagome lattice. This lattice displays strong geometric frustration, which results in a flat band. For fermions, this makes the kagome antiferromagnet a candidate for studying the quantum spin liquid phase. For bosons, frustration has been predicted to e.g. give rise to interaction-driven condensation and a supersolid state. Since the flat band is the highest-lying subband, we plan to access it by creating a negative absolute temperature state. Our experiment is capable of cooling bosonic ⁸⁷Rb and ³⁹K and fermionic ⁴⁰K to quantum degeneracy, thus enabling studies of strongly correlated physics in bosons, fermions, and mixtures.

 

We implement the kagome lattice by superimposing a triangular lattice of 532 nm light and a honeycomb lattice of 1064 nm light, which effectively cancels out every fourth lattice site of the triangular lattice. Our quantum simulator is therefore capable of performing experiments with the triangular and honeycomb lattices as well. In addition to momentum-resolved imaging via time-of-flight, the apparatus includes a quantum gas microscope (QGM), which will enable access to local observables. I will report on our progress towards bosons in a flat band and towards single-site-resolved imaging with our quantum gas microscope.