A prey–predator system with intelligent pursuit and evasion is studied by means of computer simulations. It is found that the model exhibits a coexistence state between prey and predators. In this state and depending on the parameters, the system may evolve toward two different regimes,...

We consider a three-component model of rodlike molecules AA, BB, and AB, confined to the bonds of the honeycomb or three-coordinated Bethe lattice, and with three-body interactions between the molecular ends near a common lattice site. The model is equivalent to an Ising model on an associated...

The work deals with the theoretical study of domain structures in a ferrofluid, filling a thin flat gap with hard non-magnetic walls, placed into magnetic field, perpendicular to the gap plane. Two experimentally observed types of these structures are considered. The first one is the direct...

A new notion of matrix order indices which relates the matrix norm and its trace is introduced. These indices can be defined for any given matrix. They are especially important for matrices describing many-body systems, equilibrium as well as nonequilibrium, for which the indices present a...

A surprising physical interpretation of the replica number n was unveiled in the study of the equilibrium properties of the coupled dynamics of fast Ising spins and slow interactions: n is the ratio of the characteristic temperatures of the spin and the interaction systems and can take on any...

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...

In the present work we study the critical properties of the ferromagnetic three-color Ashkin–Teller model (3AT) by means of a Migdal–Kadanoff renormalization group approach on a diamond-like hierarchical lattice. The analysis of the fixed points and flux diagram of the recursion relations is...

When DNA molecules are heated they undergo a denaturation transition by which the two strands of the molecule are separated and become unbound. Experimental studies strongly indicate that the denaturation transition is first order. The main theoretical approach to study this transition,...

First-order phase transitions in finite systems can be defined through the bimodality of the distribution of the order parameter. This definition is equivalent to the one based on the inverted curvature of the thermodynamic potential. Moreover we show that it is in a one-to-one correspondence...

The relation between thermodynamic phase transitions in classical systems and topology changes in their state space is discussed for systems in which equivalence of statistical ensembles does not hold. As an example, the spherical model with mean field-type interactions is considered. Exact...