Sökning: "Discrete Breathers"

Visar resultat 1 - 5 av 7 avhandlingar innehållade orden Discrete Breathers.

  1. 1. Effects of aperiodic order for Josephson junction arrays and discrete breathers

    Författare :Erik Lennholm; Linköpings universitet; []
    Nyckelord :Aperiodic order; Josephson junction array; Discrete breather;

    Sammanfattning : Effects of the combination of nonlinearities and aperiodic order is studied in this thesis. The nonlinear systems considered are Josephson junction arrays (JJA) and Fermi-Pasta-Ulam (FPU) lattices. Both systems are discrete and one-dimensional. The traveling waves in a JJA are solitons, i. LÄS MER

  3. 2. Nonlinear localization in discrete and continuum systems : applications for optical waveguide arrays

    Författare :Michael Öster; Linköpings universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP;

    Sammanfattning : An introcludion to the formation of coherent structures in spatially discrete and continuous systems is given. Of special interest is the phenomenon of nonlinear localization, where the self-focusing of an excitation is balanced by a dispersive process. LÄS MER

  4. 3. Theoretical studies of Bose-Hubbard and discrete nonlinear Schrödinger models : Localization, vortices, and quantum-classical correspondence

    Författare :Peter Jason; Magnus Johansson; Irina Yakimenko; Vladimir Konotop; Linköpings universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : This thesis is mainly concerned with theoretical studies of two types of models:  quantum mechanical Bose-Hubbard models and (semi-)classical discrete nonlinear Schrödinger (DNLS) models.Bose-Hubbard models have in the last few decades been widely used to describe Bose-Einstein condensates placed in periodic optical potentials, a hot research topic with promising future applications within quantum computations and quantum simulations. LÄS MER

  5. 4. Physical effects of nonlinearity in discrete onedimensional systems with spatial variations

    Författare :Erik Lennholm; Luis Mario Floria; Linköpings universitet; []
    Nyckelord :;

    Sammanfattning : Physical properties of a solid are affected, to a very high degree, by the spatial structure of the material at hand. This thesis is concerned with such effects in nonlinear systems. In itself, nonlinearity is a subject on the move, and more and more areas of physics tend to take nonlinear effects into account. LÄS MER

  7. 5. Comparisons between classical and quantum mechanical nonlinear lattice models

    Författare :Peter Jason; Magnus Johansson; Jonas Larson; Linköpings universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Discrete Breathers; Bose-Einstein-Condensation; Instabilities; Oscillatory Instabilities; Classical-Quantum correspondence; Bose-Hubbard model; DNLS; discrete nonlinear Schrödinger equation; nonlinear; nonlinear lattice models; compacton;

    Sammanfattning : In the mid-1920s, the great Albert Einstein proposed that at extremely low temperatures, a gas of bosonic particles will enter a new phase where a large fraction of them occupy the same quantum state. This state would bring many of the peculiar features of quantum mechanics, previously reserved for small samples consisting only of a few atoms or molecules, up to a macroscopic scale. LÄS MER