Nonlinear Lattice Waves in Random Potentials

Abstract

Localization of waves by disorder is a fundamental physical problem encompassing a diverse spectrum of theoretical, experimental and numerical studies in the context of metal-insulator transition, quantum Hall effect, light propagation in photonic crystals, and dynamics of ultra-cold atoms in optical arrays. Large intensity light can induce nonlinear response, ultracold atomic gases can be tuned into an interacting regime, which leads again to nonlinear wave equations on a mean field level. The interplay between disorder and nonlinearity, their localizing and delocalizing effects is currently an intriguing and challenging issue in the field. We will discuss recent advances in the dynamics of nonlinear lattice waves in random potentials. In the absence of nonlinear terms in the wave equations, Anderson localization is leading to a halt of wave packet spreading. Nonlinearity couples localized eigenstates and, potentially, enables spreading and destruction of Anderson localization due to nonintegrability, chaos and decoherence. The spreading process is characterized by universal subdiffusive laws due to nonlinear diffusion. We review extensive computational studies for one- and two-dimensional systems with tunable nonlinearity power. We also briefly discuss extensions to other cases where the linear wave equation features localization: Aubry-Andre localization with quasiperiodic potentials, Wannier-Stark localization with dc fields, and dynamical localization in momentum space with kicked rotors.

45 pages, 19 figures

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Cited by in corpus (9)

• Nonlinear Coherent Structures in Granular Crystals
• Characteristics of chaos evolution in one-dimensional disordered nonlinear lattices
• Superdiffusive Transport and Energy Localization in Disordered Granular Crystals
• Nanoptera in a Period-2 Toda Chain
• Scattering of Waves by Impurities in Precompressed Granular Chains
• Interaction-induced connectivity of disordered two-particle states
• Spreading, Nonergodicity, and Selftrapping: a puzzle of interacting disordered lattice waves
• Nonlinear dynamics and chaos in multidimensional disordered Hamiltonian systems
• Energy spreading, equipartition and chaos in lattices with non-central forces