INHOMOGENEOUS GLAUBER DYNAMICS AND THE PROCESS OF CRYSTALLIZATION OF A LATTICE-GAS

The model under consideration is a hard-core lattice gas in an externa l potential on a Bethe lattice with nonequilibrium time evolution gove rned by Glauber dynamics. A hierarchical decoupling of nonequilibrium correlations, motivated by and asymptotically providing the exact form of equilibrium multisite correlations in the inhomogeneous potential regime, is proposed. Application is made to the process of lattice gas crystallization, at high activity, from a spatially homogeneous fluid phase to an equilibrium crystal phase with unequal sublattice densiti es. The first few levels of the hierarchical decoupling give a consist ent picture of two kinds of nonequilibrium instabilities-one leading t o a sublattice density bifurcation, the other associated with an abrup t increase in densities and correlations in time.