Sökning: "Institutionen för astronomi och teoretisk fysik"
Visar resultat 1 - 5 av 145 avhandlingar innehållade orden Institutionen för astronomi och teoretisk fysik.
1. Gravitational perturbations in plasmas and cosmology
Sammanfattning : Gravitational perturbations can be in the form of scalars, vectors or tensors. This thesis focuses on the evolution of scalar perturbations in cosmology, and interactions between tensor perturbations, in the form of gravitational waves, and plasma waves. LÄS MER
2. Theoretical Atomic Spectroscopy of Earthbound and Stellar Plasma
Sammanfattning : Motivated by spectroscopic analysis of astrophysical and laboratory plasma, this thesis concerns the fundamental structure and spectral properties of atoms and their ions. The multiconfiguration Dirac-Hartree-Fock (MCDHF) method is used to predict the emission or absorption of radiation, by atomic systems in general, and of heavy and highly charged ions in particular. LÄS MER
3. The Electronic Structure of Organic Molecular Materials : Theoretical and Spectroscopic Investigations
Sammanfattning : In the present thesis the electronic properties of two organic molecules were studied by means of density functional theory (DFT) in connection to their possible applications in organic photovoltaics and molecular spintronics respectively.The first analysed system is the C60 derivative PCBM extensively used in polymer solar cells for the charge separation process. LÄS MER
4. A Study of Grain Drift in C Stars : Theoretical Modeling of Dust-Driven Winds in Carbon-Rich Pulsating Giant Stars
Sammanfattning : A major fraction of stars will pass through a short period of dramatic events in their final evolutionary stage. Low- to intermediate-mass stars, studied here, are stripped of their outer parts in a slow massive wind. This mass loss reshapes both the star and the surrounding medium. LÄS MER
5. Aspects of the Duality between Supersymmetric Yang-Mills Theory and String Theory
Sammanfattning : This thesis deals with three topics related to the Ads/CFT correspondence. In Paper I, solutions describing the geometry of fractional D1-branes of Type IIB string theory are presented. The running coupling constant is computed on the gauge theory side. LÄS MER