Characterizing the antiferromagnetic ordering of fermions in a compensated optical lattice*

We realize the Fermi-Hubbard model with fermionic $^{6}$Li atoms in a three-dimensional, red-detuned optical lattice. The lattice is compensated by the addition of three blue-detuned gaussian beams which overlap each of the lattice laser beams, but are not retro-reflected. Using the compensated lattice potential, we have reached temperatures low enough to produce antiferromagnetic (AF) spin correlations, which we detect via Bragg scattering of light. The variation of the measured AF correlations as a function of the Hubbard interaction strength, $U/t$, provides a way to determine the temperature of the atoms in the lattice by comparison with quantum Monte Carlo calculations. This method suggests our temperature is in the range of 2-3 times the N\'{e}el ordering temperature. In this poster we present our Bragg scattering results along with our studies of the effect of the compensating potential in helping us cool the atoms in the lattice and also enlarge the size of the AF phase.\footnote{C. J. M. Mathy et al., Phys. Rev. A \textbf{86}, 023606 (2011)}