A Closer Look at Fermions in Optical Lattices

Quantum gases of interacting fermionic atoms in optical lattices promise to shed new light on the low-temperature phases of Hubbard-type models, such as spin-ordered phases or, in particular, on possible $d$-wave superconductivity. However, reaching the very low temperatures required necessitates the implementation of novel cooling schemes. As a first step towards this goal, we employ high-resolution imaging together with radio-frequency spectroscopy in order to spatially resolve the in-trap distributions of singly and doubly-occupied lattice sites after having loaded a quantum degenerate two-component Fermi gas of $^{40}$K atoms into a three-dimensional optical lattice geometry. Here, I will report on our recent progress towards the observation and characterization of a fermionic Mott insulator, together with an outlook on future steps towards lowering the temperature in the lattice.