Computer simulation of driven diffusive systems with exchanges

The field-driven Kawasaki model with a fraction p admixture of Glauber dynamics is studied by computer simulation:p=0 corresponds to the order-parameter-onserving driven diffusive system, while p=1 is the equilibrium Ising model. For p=0.1 our best estimates of critical exponents based on a system of size 4096×128 are β≈0.22, η^RS≈0.45, and v_{{norm of matrix}}≈v_⊥≈1. These exponents differ from both the values predicted by a field-theoretic method for p=0 and those of the equilibrium Ising model. Anisotropic finite-size scaling analyses are carried out, both for subsystems of the large system and for fully periodic systems. The results of the latter, however, are inconsistent, probably due to the complexity of the size effects. This leaves open the possibility that we are in a crossover regime from p=0 to p≠0 and that our critical exponents are "effective ones." For p=0 our results are consistent with the predictions v_{{norm of matrix}}>v_⊥.