Search for dissertations about: "two-dimensional models"

Showing result 1 - 5 of 242 swedish dissertations containing the words two-dimensional models.

2. 1. Improvement and Assessment of Two-Dimensional Resistivity Models Derived from Radiomagnetotelluric and Direct-Current Resistivity Data

   Author : Thomas Kalscheuer; Laust B. Pedersen; Christopher Juhlin; Roland Roberts; Heinrich Brasse; Uppsala universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Electromagnetic geophysics; radiomagnetotellurics; direct-current resistivity; displacement currents; dielectric effect; non-linearity; inversion; regularization; two-dimensional model; model variance; model resolution; data resolution; Geophysics; Geofysik;

   Abstract : Two-dimensional (2-D) models of electrical resistivity are improved by jointly inverting radiomagnetotelluric (RMT) and direct-current resistivity (DCR) data or by allowing for displacement currents in the inversion of RMT data collected on highly resistive bedrock. Uniqueness and stability of the 2-D models are assessed with a model variance and resolution analysis that allows for the non-linearity of the inverse problem. READ MORE

4. 2. Light scattering in two-dimensional inhomogeneous paper : Analysis using general radiative transfer theory

   Author : Madhuri Nukala; Egmont Porten; Jana Mendrok; Mittuniversitetet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES;

   Abstract : Modeling light scattering is important in diverse reasearch fields such as paper and print, optical tomography, remote sensing and also in computer rendering of im­ages. Particularly in paper and printing industry light scattering simulations play a significant role in understanding the optical response of paper in relation to its properties. READ MORE

5. 3. Theoretical Studies of Two-Dimensional Magnetism and Chemical Bonding

   Author : Oleksiy Grechnyev; Olle Eriksson; Alexander Lichtenstein; Uppsala universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Physics; spin Hamiltonians; quantized spin models; Heisenberg model; spin waves; self-consistent spin-wave theory; dipolar interaction; density functional theory; chemical bonding; overlap population; MAX phases; metal hydrides; Fysik; Physics; Fysik;

   Abstract : This thesis is divided into two parts. In the first part we study thermodynamics of the two-dimensional Heisenberg ferromagnet with dipolar interaction. This interaction breaks the conditions of the Mermin-Wagner theorem, resulting in a finite transition temperature. READ MORE

6. 4. Microscopic Theory of Exciton Dynamics in Two-Dimensional Materials

   Author : Samuel Brem; Chalmers tekniska högskola; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; exciton-phonon interaction; van der Waals materials; relaxation dynamics; excitons; 2D materials; density matrix formalism;

   Abstract : Transition Metal Dichalcogenides (TMDs) present a giant leap forward towards the realization of nanometer-sized quantum devices. As a direct consequence of their truly two-dimensional character, TMDs exhibit a strong Coulomb-interaction, leading to the formation of stable electron-hole pairs, so-called excitons. READ MORE

7. 5. On string integrability : A journey through the two-dimensional hidden symmetries in the AdS/CFT dualities

   Author : Valentina Giangreco Marotta Puletti; Konstantin Zarembo; Gleb Arutyunov; Uppsala universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; String Theory; AdS-CFT correspondence; Integrable Field theory; Sigma models; S-matrix; Factorized Scattering; Physics; Fysik; Mathematical physics; Matematisk fysik; Theoretical Physics; teoretisk fysik;

   Abstract : One of the main topics in the modern String Theory are the conjectured string/gauge (AdS/CFT) dualities. Proving such conjectures is extremely difficult since the gauge and string theory perturbative regimes do not overlap. In this perspective, the discovery of infinitely many conserved charges, i.e. READ MORE