CRITICAL PROPERTIES OF 3D ISING SYSTEMS WITH NON-HAMILTONIAN DYNAMICS

We investigate two three-dimensional Ising models with non-Hamiltonian Glauber dynamics. The transition probabilities of these models can, j ust as in the case of equilibrium models, be expressed in terms of Bol tzmann factors depending only on the interacting spins and the bond st rengths. However, the bond strength associated with each lattice edge assumes different values for the two spins involved. The first model h as cubic symmetry and consists of two sublattices at different tempera tures. In the second model a preferred direction is present. These two models are investigated by Monte Carlo simulations on the Delft Ising System Processor. Both models undergo a phase transition between an o rdered and a disordered state. Their critical properties agree with Is ing universality. The second model displays magnetization bistability.