Enlarging and cooling the Néel state in an optical lattice

We propose an experimental scheme to favor both the realization and the detection of the Néel state in a two-component gas of ultracold fermions in a three-dimensional simple-cubic optical lattice. By adding three compensating Gaussian laser beams to the standard three pairs of retroreflected lattice beams, and adjusting the relative waists and intensities of the beams, one can significantly enhance the size of the Néel state in the trap, thus increasing the signal of optical Bragg scattering. Furthermore, the additional beams provide for adjustment of the local chemical potential and the possibility to evaporatively cool the gas while in the lattice. Our proposals are also relevant to efforts to realize other many-body quantum phases in optical lattices.