The critical behaviour of the quenched bond-diluted Z(4) ferromagnetic model on the square lattice is investigated within a real-space renormalization-group scheme. The phase diagram as well as the correlation-length and crossover critical exponents are obtained, and the universality classes of...

The quenched site-diluted Ising ferromagnet on a square lattice, for which each site is occupied or empty with probabilities p and 1 − p, respectively, is studied numerically through damage-spreading procedures. By making use of the Glauber dynamics, the percolation threshold pc is estimated....

In this paper we study the spin wave transmission spectra of quasiperiodic magnetic multilayers following Fibonacci, double period and Thue–Morse sequences. We consider multilayers that are composed of two simple cubic ferromagnetic materials surrounded by two semi-infinite slabs of a third...

We study the spreading of damage D(t) in the antiferromagnetic Ising model on a triangular lattice in the presence of a magnetic field by using Glauber dynamics. Although the damage spreads (chaotic behavior) for all finite values of the field and temperature, there are two distinct...

We have studied the time dependence of the damage-spreading in a 2-dimensional Ising Model using time series analysis. We have found that the signal has a Hurst exponent 0.5 in high temperatures, and it approaches 1 near the temperature TD where the damage goes to zero. We have also measured the...

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...

We propose a method to characterize quasi-periodic chains, based on the transmission probabilities. We consider finite layers which are building up following the Fibonaci, Thue-Morse and Cantor sequences. The spectra show an undoubtedly fractal behavior, with a distinct appearence for each...

The two-dimensional ferromagnetic anisotropic Ashkin–Teller model is investigated through a real-space renormalization-group approach. The critical frontier, separating five distinct phases, recovers all the known exact results for the square lattice. The correlation length (νT) and crossover...

Given an arbitrary probability distribution and a nondegenerate energy spectrum, so that a mean energy U can be computed, we derive the partition function Z and the entropic functional S that satisfy the basic relation dU=TdS. The procedure is illustrated by considering examples of typical...

The dynamics of the approach to equilibrium of the hydrogen atom is investigated numerically through a Monte Carlo procedure. We show that, before approaching ionization, the hydrogen atom may live in a quasi-equilibrium state, characterized by aging, whose duration increases exponentially as...