Francisco A. Tamarit

Rotators with long-range interactions: connection with the mean-field approximation

We analyze the equilibrium properties of a chain of ferromagnetically coupled rotators which interact through a force that decays as r(-alpha) where r is the interparticle distance and alpha>/=0. By integrating the equations of motion we obtain the microcanonical time averages of both the magnetization and the kinetic energy. We detect three different regimes depending on whether alpha belongs to the intervals [0,1), (1,2), or (2,infinity). For 0<alpha<1, the microcanonical averages agree, after a scaling, with those obtained in the canonical ensemble for the mean-field case (alpha = 0). This correspondence offers a mathematically tractable way of dealing with systems governed by slowly decaying long-range interactions.

Long-range interactions and nonextensivity in ferromagnetic spin models

The Ising model with ferromagnetic interactions that decay as

Aging in an infinite-range Hamiltonian system of coupled rotators.

\frac{1}{{r}^{\ensuremath{\alpha}}}

Evidence of exactness of the mean-field theory in the nonextensive regime of long-range classical spin models

is analyzed in the nonextensive regime

Emergent self-organized complex network topology out of stability constraints.

0l~\ensuremath{\alpha}l~d

Spin reorientation transition and phase diagram of ultrathin ferromagnetic films

, where the thermodynamic limit is not defined. In order to study the asymptotic properties of the model in the

Dynamics of ferromagnetic spherical spin models with power law interactions: exact solution

N\ensuremath{\rightarrow}\ensuremath{\infty}

Stripe-tetragonal first-order phase transition in ultrathin magnetic films

limit (

Self-organized criticality in a model of biological evolution with long-range interactions

N

Ising nematic phase in ultrathin magnetic films : a Monte Carlo study

being the number of spins) we propose a generalization of the Curie-Weiss model, for which the