KINETIC LATTICE MODELS OF DISORDER

We study a class of stochastic Ising (or interacting particle) systems that exhibit a spatial distribution of impurities that change with ti me. it may model, for instance, steady nonequilibrium conditions of th e kind that may be induced by diffusion in some disordered materials. Different assumptions for the degree of coupling between the spin and the impurity configurations are considered. Two interesting well-defin ed limits for impurities that behave autonomously are (i) the standard (i.e., quenched) bond-diluted, random-field, random-exchange, and spi n-glass Ising models, and (ii) kinetic variations of these standard ca ses in which conflicting kinetics simulate fast and random diffusion o f impurities. A generalization of the Mattis model with disorder that describes a crossover from the equilibrium case (i) to the nonequilibr ium case (ii) and the microscopic structure of a generalized heat bath are explicitly worked out as specific realizations of our class of mo dels. We sketch a simple classification of transition rates for the ti me evolution of the spin configuration based on the critical behavior that is exhibited by the models in case (ii). The latter are shown to have an exact solution for any lattice dimension for some special choi ce of rates.