Search for dissertations about: "lattice models"

Showing result 1 - 5 of 139 swedish dissertations containing the words lattice models.

2. 1. Correlated materials : models and methods

   Author : Hugo Strand; Göteborgs universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; correlated electrons; Hubbard model; multiband Hubbard model; dynamical mean field theory; exact diagonalization; Landau theory; Mott metal-insulator transition; Gutzwiller method; many-body point group symmetry; ironchalcogenides; Kanamori interaction; Slater-Condon interaction;

   Abstract : This thesis encompass a series of studies on methods and models for electron systems with local interactions, relevant for correlated materials. The first study focus on the canonical model for local correlation, the Hubbard model. READ MORE

4. 2. Topological band theory and Majorana fermions : With focus on self-consistent lattice models

   Author : Kristofer Björnson; Annica M. Black-Schaffer; Jonas Fransson; Olle Eriksson; Andrei Bernevig; Uppsala universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Topology; Majorana; superconductivity; material physics; numerical calculations; tight-binding; mean-field;

   Abstract : One of the most central concepts in condensed matter physics is the electronic band structure. Although band theory was established more than 80 years ago, recent developments have led to new insights that are formulated in the framework of topological band theory. READ MORE

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

   Author : Peter Jason; Magnus Johansson; Jonas Larson; Linköpings universitet; []
   Keywords : 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;

   Abstract : 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. READ MORE

6. 4. Roughening in dimer models : Random matrix statistics and surface fluctuations

   Author : Scott Mason; Kurt Johansson; Alexey Bufetov; KTH; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Matematik; Mathematics;

   Abstract : The field of mathematical statistical mechanics sits at the intersection of probability theory and mathematical physics. It consists of the rigorous analysis of models in statistical mechanics, such as dimer and lattice models - of which the Ising model is a classical example. READ MORE

7. 5. Combinatorics of solvable lattice models with a reflecting end

   Author : Linnea Hietala; Göteborgs universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; mathematics; mathematical physics; six-vertex model; eight-vertex SOS model; three-color model; reflecting end; domain wall boundary conditions; partition function; determinant formula; XYZ spin chain; alternating sign matrices; special polynomials; positive coefficients;

   Abstract : I den här avhandlingen studerar vi några exakt lösbara, kvantintegrerbara gittermodeller. Izergin bevisade en determinantformel för partitionsfunktionen till sexvertexmodellen på ett gitter av storlek n × n med Korepins domänväggrandvillkor (domain wall boundary conditions – DWBC). READ MORE