In this paper we compute exactly the ground state energy and entropy of the dilute ferromagnetic Ising model. The two thermodynamic quantities are also computed when a magnetic field with random locations is present. The result is reached in the replica approach frame by a class of replica order...

In this paper, we analyze an evolving model with local information which can generate a class of networks by choosing different values of the parameter p. The model introduced exhibits the transition from unweighted networks to weighted networks because the distribution of the edge weight can be...

We present here a conjecture about the equivalence between the noise density of states of a system governed by a generalized Langevin equation and the fluctuation in the energy density of states in a Hamiltonian system. We present evidence of this for a disordered Heisenberg system.

The Internet infrastructure is not virtual: its distribution is dictated by social, geographical, economical, or political constraints. However, the infrastructure's design does not determine entirely the information traffic and different sources of complexity such as the intrinsic heterogeneity...

We present a comparative study of the effects of random and aperiodically distributed interactions on the critical behavior of a model for two interacting polymers on a diamond hierarchical lattice. The problem is formulated in terms of exact renormalization-group (RG) recursion relations. In...

We investigate the adaptation of random boolean networks that are a model for regulatory gene networks. The model considers a general genetic algorithm and a fitness function that takes into account the full network dynamical behavior. We propose a mathematical function to quantify the...

The world-wide web forms a large directed graph, whose vertices are documents and edges are links pointing from one document to another. Here we demonstrate that despite its apparent random character, the topology of this graph has a number of universal scale-free characteristics. We introduce a...

In a discrete disordered system one is interested in computing the averaged Green's function 〈Gij〉. Using the supersymmetry formulation as a starting point, we derive a renormalization group flow equation for the effective probability distribution of a subsystem of fixed size, which...

We study chaotic functions that are exact solutions to nonlinear maps. A generalization of these functions (which cannot be expressed as a recursive procedure anymore) can produce truly random sequences. Even if the initial conditions are known exactly, the next values are in principle...

We analyse the influence of diagonal disorder (random site energy) on charge density wave (CDW) and superconductivity (SS) in local pair systems which are described by the model of hard core charged bosons on a lattice. This problem was previously studied within the mean field approximation for...