Towards Quantum Simulation of the 2D Fermi Hubbard Model - Development of a Local Probe of Density and Spin Ordering.

摘要

We report on the results obtained across the three-year AFOSR- supported project, whose purpose was to study ultracold lattice fermions. We built a ultrahigh vacuum system with exceptional optical access, used both to create an optical lattice and to imagine atoms in situ. We used 405-nm light to laser cool potassium-40, the fermionic isotope of interest. Our data provides an upper bound on the ionization cross section, which is sufficiently low that high-resolution imaging using this optical transition should be feasible. With ultracold rubidium-87, we observe a quantum phase transition between a lattice superfluid and a Mott insulator. We are also able to create a degenerate Fermi gas of potassium-40, and load it into the lowest band of an optical lattice.