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 asymmetric and anisotropic bimodal probability distribution P(hi)=pδ(hi−h0)+qδ(hi+λ∗h0), where the site probabilities p,q...

A generalization of the pure site and pure bond percolation problems called site–bond percolation on a triangular lattice is studied. Motivated by considerations of cluster connectivity, two distinct schemes (denoted as S∩B and S∪B) for site–bond percolation are used. In S∩B (S∪B),...

We present results of theoretical study of quasielastic behavior of ferrofluid filling a thin flat gap, placed into perpendicular magnetic field. When the field exceeds a certain critical magnitude, magnetic particles form dense discrete domains, elongated along the field, and linking the gap...

We study the damage spreading phenomena in two different ways in an opinion dynamics model introduced recently. This kinetic exchange type model is characterized by a fraction q of negative interactions and shows the presence of an order–disorder transition at qc. In the traditional method,...

We study the effects of including a distribution of valuable or attractive sites in a two-dimensional lattice in self-organizing social hierarchies. Agents move aleatorily except in the case where an attractive site is located in their neighborhood. We find that the transition between an...

The Pirogov–Sinai theory of phase transitions is used to prove the existence of ordered molecular phases at low temperatures in statistical mechanical models for several types of molecular systems. A three-dimensional lattice gas containing two molecular mirror images (enantiomers) was proved...

We examine some aspects of the recent results by Binder [Physica A 319 (2003) 99]. The equilibrium formation/dissolution of droplets in finite systems is discussed in the context of the canonical and the grand canonical distributions.

The zeros of the partition function of the ferromagnetic q-state Potts model with long-range interactions in the complex-q plane are studied in the mean-field case, while preliminary numerical results are reported for the finite 1d chains with power-law decaying interactions. In both cases, at...

In this article, the density profiles in the totally asymmetric simple exclusion processes (TASEPs) with both Langmuir kinetics and the local inhomogeneity, have been investigated by Monte Carlo simulations and a mean-field theory. The model is relevant for the understanding of the biological...

When confining vacuum fluctuations between two identical walls, the Casimir force manifests itself as a mutual attraction of the walls. When confining concentration fluctuations of a binary liquid mixture, an analogous force should exist near the critical temperature TC; it is called the critical...