Effective Field Theory of Inflation and its Applicationin Calculating Primordial Non-Gaussianities

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Vakili, Mohammad Javad | 2011

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Type of Document: M.Sc. Thesis
Language: Farsi
Document No: 41957 (04)
University: Sharif University of Technology
Department: Physics
Advisor(s): Golshani, Mahdi; Firouzjahi, Hassan
Abstract:
In this thesis we perform the method for calculating primordial non- Gaussianity for a generic single-field inflationary model and compare the results of important models such as DBI inflation and slow roll inflation. Then, we will show how to extract potentially observable quantities from 3 point correlation functions of gauge invariant curvature perturbations, like the size and shape of non-Gaussianities. Then,we will review the effective field theory approach to inflation that allows us to unify all inflationary models and characterize high energy corrections to simple slow roll model. We use this approach to estimate the size of non-Gaussianities in various limit. Furthermore, we study one of the most important alternatives to slow-roll inflation called ghost inflation which is a limit of the effective theory and is inspired by a modification of gravity on large distances. Besides, we study the strong coupling problem for models with small speed of sound and large non-Gaussianity. Finally we explore the experimental bounds on the speed of sound from WMAP 5 year data
Keywords:
Inflation ; Primordial Non-Gaussianities ; Inflation Effective Field Theory ; Ghost Inflation