Sökning: "Kosmologi"

Visar resultat 1 - 5 av 475 avhandlingar innehållade ordet Kosmologi.

1. 1. Supersymmetry vis-à-vis Observation : Dark Matter Constraints, Global Fits and Statistical Issues

   Författare :Yashar Akrami; Joakim Edsjö; Lars Bergström; Roberto Trotta; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; supersymmetry; cosmology of theories beyond the Standard Model; dark matter; gamma rays; dwarf galaxies; direct detection; statistical techniques; scanning algorithms; genetic algorithms; statistical coverage; Astroparticle physics; Astropartikelfysik; Cosmology; Kosmologi; Astroparticle physics; Astropartikelfysik; teoretisk fysik; Theoretical Physics;

   Sammanfattning : Weak-scale supersymmetry is one of the most favoured theories beyond the Standard Model of particle physics that elegantly solves various theoretical and observational problems in both particle physics and cosmology. In this thesis, I describe the theoretical foundations of supersymmetry, issues that it can address and concrete supersymmetric models that are widely used in phenomenological studies. LÄS MER

3. 2. Observations of distant supernovae and cosmological implications

   Författare :Rahman Amanullah; Ariel Goobar; Adam Riess; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; cosmological parameters; cosmology; astro physics; supernovae; type Ia supernova; Cosmology; Kosmologi;

   Sammanfattning : Type Ia supernovae can be used as distance indicators for probing the expansion history of the Universe. The method has proved to be an efficient tool in cosmology and played a decisive role in the discovery of a yet unknown energy form, dark energy, that drives the accelerated expansion of the Universe. LÄS MER

4. 3. Inhomogeneous cosmologies with clustered dark energy or a local matter void

   Författare :Michael Blomqvist; Edvard Mörtsell; Pedro Ferreira; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; dark energy; type Ia supernova; inhomogeneous; Cosmology; Kosmologi; Astronomy; astronomi;

   Sammanfattning : In the standard model of cosmology, the universe is currently dominated by dark energy in the form of the cosmological constant that drives the expansion to accelerate. While the cosmological constant hypothesis is consistent with all current data, models with dynamical behaviour of dark energy are still allowed by observations. LÄS MER

5. 4. Cosmological aspects of universal extra dimensions

   Författare :Torsten Bringmann; Lars Bergström; Pierre Binetruy; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Cosmology; dark matter; extra dimensions; Cosmology; Kosmologi;

   Sammanfattning : It is an intriguing possibility that our world may consist of more than three spatial dimensions, compactified on such a small scale that they so far have escaped detection. In this thesis, a particular realization of this idea -- the scenario of so-called 'universal extra dimensions' (UED) -- is studied in some detail, with a focus on cosmological consequences and appplications. LÄS MER

7. 5. Gravitational perturbations in plasmas and cosmology

   Författare :Mats Forsberg; Gert Brodin; Michael Bradley; Christopher Clarkson; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; general relativity; cosmology; gravitational waves; plasma; electromagnetic waves; nonlinear waves; Plasma physics; Plasmafysik; Theory of relativity; gravitation; Relativitetsteori; gravitation; Cosmology; Kosmologi; teoretisk fysik; Theoretical Physics;

   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