We explore the "Roulette Inflation" model, a variety of two-field Kahler moduli inflation scenario with a nonstandard kinetic term derived from Type IIB string theory in the large-volume compactification. We provide an overview of the model and the cosmological tools used to compute observables. Our calculations show that entropy perturbations can account for up to 90% of Ps(k) at COBE scales. We further show that the effective single-field result over-estimates the scalar spectral index; a full calculation predicts a slightly red-shifted spectrum 0.92 < ns < 0.98. Calculation of nongaussianity from the superhorizon evolution of adiabatic modes shows that for most trajectories examined, Roulette inflation predicts small, positive fNL, which would be unmeasurable by the upcoming 9-year WMAP data and the Planck mission. Should they be detectable, momentum-dependent bispectra would provide a good discriminator between models and inflationary trajectories within models. / Nous etudions le modele d'inflation de type "Roulette", un modele base sur la relaxation de modules de Kahler sur une variete Calabi-Yau, ayant un terme cinetique non-trivial et provenant de la theorie des cordes de Type IIB, dans le contexte de la compactification a grand volume. Nous demontrons que l'influence des perturbations d'entropie peuvent compter pour jusqu'a 90% de Ps(k) a l'echelle de COBE. Nous demontrons que le resultat effectif provenant de la theorie a un seul champ surestime ns; un calcul complet predit un spectre decale vers le rouge 0.92 < ns < 0.98. Nous calculons finalement la non-gaussianite des perturbations adiabatiques resultant de leur evolution a l'exterieur du rayon de Hubble, et arrivons a des predictions de fNL ≪ 1, ce qui ne serait pas mesurable par les observations des prochaines annees. Toutefois, s'il s'avere possible de detecter un bispectre dependant du nombre d'onde k, ceci servirait d'excellent moyen de diff´erentier divers modeles d'inflation.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.21998 |
| Date | January 2008 |
| Creators | Vincent, Aaron |
| Contributors | James M Cline (Internal/Supervisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Science (Department of Physics) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | Electronically-submitted theses. |
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