Abstract
We numerically investigate the characteristics of chaos evolution during wave-packet spreading in two typical one-dimensional nonlinear disordered lattices: the Klein-Gordon system and the discrete nonlinear Schrödinger equation model. Completing previous investigations [Ch. Skokos et al., Phys. Rev. Lett. 111, 064101 (2013)], we verify that chaotic dynamics is slowing down for both the so-called weak and strong chaos dynamical regimes encountered in these systems, without showing any signs of a crossover to regular dynamics. The value of the finite-time maximum Lyapunov exponent decays in time as , with being different from the value observed in cases of regular motion. In particular, (weak chaos) and (strong chaos) for both models, indicating the dynamical differences of the two regimes and the generality of the underlying chaotic mechanisms. The spatiotemporal evolution of the deviation vector associated with reveals the meandering of chaotic seeds inside the wave packet, which is needed for obtaining the chaotization of the lattice's excited part.
3 More- Received 9 September 2018
DOI:https://doi.org/10.1103/PhysRevE.98.052229
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