Using Wang–Landau entropic sampling we study the Ising model in the framework of microcanonical ensemble (fixed magnetization). We are working for lattice size up to 1500×1500 in two dimensions and 100×100×100 in three dimensions. As we approach the coexistence curve from inside, varying...

The Ising model in the presence of a random field is investigated within the mean field approximation based on Landau expansion. The random field is drawn from the trimodal probability distribution P(hi)=pδ(hi−h0)+qδ(hi+h0)+rδ(hi), where the probabilities p,q,r take on values within the...

The Ising model, in the presence of a random field, is investigated within the mean-field approximation based on Landau expansion. The random field is drawn from the bimodal probability distribution P(h)=pδ(h−h0)+(1−p)δ(h+h0), where the probability p assumes any value within the interval...

We use a recently developed cluster algorithm for the Baxter–Wu model to study characteristic features of its behavior. Magnetic scaling properties of the model are investigated for second-order phase transitions. We improve significantly the accuracy of Monte Carlo simulation results and we...