Universal behavior in the static and dynamic properties of the $\alpha$-XY model

Abstract

The $\alpha$-XY model generalizes, through the introduction of a power-law decaying potential, a well studied mean-field hamiltonian model with attractive long-range interactions. In the $\alpha$-model, the interaction between classical rotators on a lattice is gauged by the exponent $\alpha$ in the couplings decaying as $r^{\alpha }$, where $r$ are distances between sites. We review and comment here a few recent results on the static and dynamic properties of the $\alpha$-model. We discuss the appropriate $\alpha$ dependent rescalings that map the canonical thermodynamics of the $\alpha$-model into that of the mean field model. We also show that the chaotic properties of the model, studied as a function of $\alpha$ display an universal behaviour.

23 pages, REVTEX 9 eps figures included. Talk presented at the Int. Conf. on "Classical and Quantum Complexity and Nonextensive Thermodynamics", Denton (Texas) April 3-6 2000 Revised version, accepted for publication in Chaos Solitons and Fractals