Дата и время публикации : 1998-02-28T10:53:07Z
Авторы публикации и институты :
Thierry Dauxois
Stefano Ruffo
Alessandro Torcini
Ссылка на журнал-издание: J. de Physique IV, 8 (1998) Pr6-147
Коментарии к cтатье: Latex, 10 pages, 5 Figs – Contribution to the Conference “Disorder and Chaos” held in memory of Giovanni Paladin (Sept. 1997 – Rome) – submitted to J. de Physique
Первичная категория: cond-mat.stat-mech
Все категории : cond-mat.stat-mech, chao-dyn, cond-mat.dis-nn, nlin.CD, nlin.SI, solv-int
Краткий обзор статьи: An analytical expression for the maximal Lyapunov exponent $lambda_1$ in generalized Fermi-Pasta-Ulam oscillator chains is obtained. The derivation is based on the calculation of modulational instability growth rates for some unstable periodic orbits. The result is compared with numerical simulations and the agreement is good over a wide range of energy densities $epsilon$. At very high energy density the power law scaling of $lambda_1$ with $epsilon$ can be also obtained by simple dimensional arguments, assuming that the system is ruled by a single time scale. Finally, we argue that for repulsive and hard core potentials in one dimension $lambda_1 sim sqrt{epsilon}$ at large $epsilon$.