Cosmic Inflation with Serrated Effective Potentials and Primordial Black Holes

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Hejazi, Mohammad Amin | 2021

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Type of Document: M.Sc. Thesis
Language: Farsi
Document No: 54611 (04)
University: Sharif University of Technology
Department: Physics
Advisor(s): Abolhasani, Ali Akbar
Abstract:
A variety of early universe models predict the formation of primordial black holes. Primordial black holes can be a candidate for a fraction or total dark matter in the universe. Moreover, mergers of these black holes can produce gravitational waves. After re-entering the horizon, having a sufficiently large amplitude, the initial fluctuations of cosmic matter can collapse to primordial black holes. This thesis studies an inflationary potential that can amplify the power spectrum of curvature perturbations up to several orders of magnitude via imposing some features on the potential. This power amplification on small scales can lead to the formation of primordial black holes. For simplicity, we first focus on models of inflation with a periodic feature in the effective potential. We use Floquet’s theorem to study the growth exponent of the perturbations in semi-analytical and numerical methods. Finally, we obtain an approximate effective Floquet exponent for inflation models with stochastic features.
Keywords:
Cosmology ; Early Universe ; Primordial Black Holes ; Cosmological Perturbations ; Dark Matter