We study combinatorial indicators related to the characteristic phase transitions associated with the optimization problems of coloring the nodes of a graph with the minimum number of colors and of finding an independent set of maximum cardinality in a graph. In particular, we investigate the...

Properties of semi-infinite (S=1) Heisenberg ferromagnet with biquadratic exchange were studied in terms of surface exchange (ε=IS/I) and biquadratic coupling (a). It was shown that a strict correlation exists, depending on ε, between the type of surface spin waves (acoustic or optical) and...

We implement the cellular automata model proposed by Stauffer and Weisbuch in 1992 to describe the response of the immune system to antigens in the presence of medications. The model contains two thresholds, θ1 and θ2, suggested by de Boer, Segel, and Perelson to present the minimum field...

Due to delays in the adaptation of production or delivery rates, supply chains can be dynamically unstable with respect to perturbations in the consumption rate, which is known as “bull-whip effect”. Here, we study several conceivable production strategies to stabilize supply chains, which...

Suppose that, in the thermodynamic limit, a single-component particle system exhibits a standard first-order transition marked by a jump in the density, ρ, at a chemical potential μσ(T). In grand canonical simulations of model fluids that realize such a transition when L→∞ (where L is the...

The problem of order–order and order–disorder transitions in the system described by the 2D antiferromagnetic Blume–Capel model in the presence of a magnetic field is studied by the Wang and Landau flat-histogram simulation method and by the classical Monte Carlo. Anomalous thermodynamic...

Two-dimensional Biham–Middleton–Levine traffic model on a N×N square lattice embedded on a Klein bottle and a projective plane is investigated by computer simulations. The behavior of the model with these boundary conditions is compared with the model under toroidal boundary conditions. Our...

Based on a recently developed algorithm for the exploration of ground states in bond-diluted lattice spin glasses, we determine the scaling of defect energies with system size for Ising spin glasses at the bond percolation threshold pc. The results can be related by well-known scaling relations...

Phase transitions of the mixed spin- 1/2 and spin-S (S≥1/2) Ising model on a three-dimensional (3D) decorated lattice with a layered magnetic structure are investigated within the framework of a precise mapping relationship to the simple spin- 1/2 Ising model on a tetragonal lattice. This...

Condensation phase transitions in polydisperse colloids are studied theoretically. For maximal simplification of calculations, a bidisperse model of the system, consisting of relatively big and small particles, is considered. Direct van der Waals interactions between big particles as well as...