NONEQUILIBRIUM CRITICAL RELAXATION IN DILUTE ISING SYSTEMS

We investigate the critical relaxation of dilute Ising systems starting from a macroscopically prepared initial state with short-range correlations. Using the methods of renormalized field theory we calculate the exponent theta' which describes the initial increase of the magnetization to second order in root epsilon, where epsilon = 4 - d. Since computer simulations of the dilute Ising model have shown that a large part of the critical region is governed by crossover phenomena, we also discuss the influence of the slow crossover on the relaxation.