| Summary: | We present Monte Carlo simulations of the lattice gas with nearest-neighbor exclusion and Kawasaki (hopping) dynamics (hard square lattice gas), under the influence of a nonuniform drive, on the square lattice. The drive, which favors motion along the +x axis and inhibits motion in the opposite direction, varies linearly in the y direction. Our lattice has rigid walls at the end points in the y direction and periodic boundaries along the drive. We find that this model has transition to a sublattice-ordered phase at a density of about 0.298, lower than in equilibrium (rhoc <FONT FACE=Symbol>@</FONT> 0.37), but somewhat higher than in the uniformly driven case at maximal bias (rhoc <FONT FACE=Symbol>@</FONT> 0.272). For smaller global densities (r < 0.33), the ordering occurs with particle accumulation in the low-drive region. Above this density we observe a surprising reversal in the density profile, with particles migrating to the high-drive region.
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