In the framework of the Fermi-Pasta-Ulam (FPU) model, we show a simple method to give an accurate analytical estimation of the maximal Lyapunov exponent at high energy density. The method is based on the computation of the mean value of the modulational instability growth rates associated to unstable modes. Moreover, we show that the strong stochasticity threshold found in the [Formula Presented] system is closely related to a transition in tangent space, the Lyapunov eigenvector being more localized in space at high energy. © 1997 The American Physical Society.
Modulational estimate for the maximal Lyapunov exponent in Fermi-Pasta-Ulam chains / Dauxois, T.; Ruffo, S.; Torcini, A.. - In: PHYSICAL REVIEW E. - ISSN 1063-651X. - 56:6(1997), pp. R6229-R6232. [10.1103/PhysRevE.56.R6229]
Modulational estimate for the maximal Lyapunov exponent in Fermi-Pasta-Ulam chains
Ruffo S.;
1997-01-01
Abstract
In the framework of the Fermi-Pasta-Ulam (FPU) model, we show a simple method to give an accurate analytical estimation of the maximal Lyapunov exponent at high energy density. The method is based on the computation of the mean value of the modulational instability growth rates associated to unstable modes. Moreover, we show that the strong stochasticity threshold found in the [Formula Presented] system is closely related to a transition in tangent space, the Lyapunov eigenvector being more localized in space at high energy. © 1997 The American Physical Society.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
