Dresden 2011 – scientific programme
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DY: Fachverband Dynamik und Statistische Physik
DY 23: Nonlinear Waves/ Nonlinear Lattices
DY 23.2: Talk
Wednesday, March 16, 2011, 14:30–14:45, ZEU 255
Strong and weak chaos regimes of wave spreading in nonlinear disordered media — •Tetyana Laptyeva, Joshua Bodyfelt, Dmitry Krimer, Charalampos Skokos, and Sergej Flach — Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Straße 38, D-01187 Dresden, Germany
The spreading behavior of multiple-site excitations was analyzed for anharmonic disordered 1-D lattices with cubic nonlinearity, where all linear modes are exponentially localized by disorder. Due to chaotic nonlinear interaction, the initial localization is destroyed and a finite part of the wave packet spreads subdiffusively [1]. In addition to our previous results [1], we find a qualitatively new dynamical regime, where the second moment m2 of the wave packet grows as t1/2, with a crossover to an asymptotic t1/3 law at larger times [2]. This novel effect is attributed to the strong chaos regime, in contrast to the previously observed weak chaos. The crossover between the regimes is controlled by the ratio of the nonlinear frequency shift and the average eigenvalue spacing of the linear problem eigenstates within one localization volume. The details of these spreading regimes were analyzed using extensive numerical simulations over large times with ensemble averaging [2].
[1] S Flach DO Krimer Ch Skokos, Phys. Rev. Lett. 102, 024101 (2009); Ch. Skokos DO Krimer S Komineas S Flach, Phys. Rev. E 79, 056211 (2009)
[2] TV Laptyeva JD Bodyfelt DO Krimer Ch Skokos S Flach, EPL 91, 30001 (2010)