title: Wave-packet spreading dynamics under a noninstantaneous nonlinearity: self-trapping, defocusing, and focusing.
abstract: Special localized wave modes show up in several physical scenarios including BEC in optical lattices, nonlinear photonic crystals, and systems with strong electron-phonon interaction. These result from an underlying nonlinear contribution to the wave equation that is usually assumed to be instantaneous. Here we demonstrate that the relaxation process of the nonlinearity has a profound impact in the wave-packet dynamics and in the formation of localized modes. We illustrate this phenomenology by considering the one-electron wave packet spreading in a C60 buckball structure whose dynamics is governed by a discrete nonlinear Schrödinger equation with a Debye relaxation of the nonlinearity. We report the full phase diagram related to the spacial extension of the asymptotic wave packet and unveil a complex wave-packet dynamical behavior.
authors.affiliation: Instituto de Física, Universidade Federal de Alagoas, Maceió, Brazil.
authors.forename: Marcelo L
authors.initials: ML
authors.lastname: Lyra
authors.forename: Rodrigo P A
authors.initials: RP
authors.lastname: Lima