Sökning: "nonlinear lattice models"

Visar resultat 1 - 5 av 7 avhandlingar innehållade orden nonlinear lattice models.

1. 1. 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

3. 2. Models for coupled active-passive population dynamics : Mathematical analysis and simulation

   Författare :Thi Kim Thoa Thieu; Adrian Muntean; Matteo Colangeli; Grigorios A. Pavliotis; Karlstads universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; pedestrian dynamics; simple exclusion process; Forchheimer flows; Skorohod equations; nonlinear coupling; heterogenous domain; homogenization; drafting; evacuation; Matematik; Mathematics;

   Sammanfattning : In this dissertation, we study models for coupled active--passive pedestrian dynamics from mathematical analysis and simulation perspectives. The general aim is to contribute to a better understanding of complex pedestrian flows. 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. Stability and Mobility of Localized and Extended Excitations in Nonlinear Schrödinger Models

   Författare :Michael Öster; Magnus Johansson; Sergej Flach; Linköpings universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Non-linear dynamics; chaos; Icke-linjär dynamik; kaos;

   Sammanfattning : This thesis is mainly concerned with the properties of some discrete nonlinear Schrödinger equations. These naturally arise in many different physical contexts as the limiting form of general dynamical lattice equations that incorporate nonlinearity and coupling. LÄS MER

7. 5. A periodically Ordered Structures in One Dimension

   Författare :Michael Hörnquist; Mads Peter Sørensen; Linköpings universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

   Sammanfattning : This thesis deals with different aspects of aperiodically ordered structures in one dimension. The approach is entirely theoretical, and the models used have various relevance for real systems. LÄS MER