Constraining inflationary scalar field models with CMB spectral distortions

The Cosmic Microwave Background (CMB) demonstrates extreme uniformity, with only small temperature anisotropies of the order of 10^(-5). These anisotropies are believed to originate from primordial density perturbations, caused by quantum fluctuations of scalar fields during the cosmic inflation. In...

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Main Author: Leskinen, Juuso
Other Authors: Faculty of Sciences, Matemaattis-luonnontieteellinen tiedekunta, Fysiikan laitos, Department of Physics, University of Jyväskylä, Jyväskylän yliopisto
Format: Licentiate thesis
Language:eng
Published: 2020
Subjects:
Online Access: https://jyx.jyu.fi/handle/123456789/69925
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author Leskinen, Juuso
author2 Faculty of Sciences Matemaattis-luonnontieteellinen tiedekunta Fysiikan laitos Department of Physics University of Jyväskylä Jyväskylän yliopisto
author_facet Leskinen, Juuso Faculty of Sciences Matemaattis-luonnontieteellinen tiedekunta Fysiikan laitos Department of Physics University of Jyväskylä Jyväskylän yliopisto Leskinen, Juuso Faculty of Sciences Matemaattis-luonnontieteellinen tiedekunta Fysiikan laitos Department of Physics University of Jyväskylä Jyväskylän yliopisto
author_sort Leskinen, Juuso
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description The Cosmic Microwave Background (CMB) demonstrates extreme uniformity, with only small temperature anisotropies of the order of 10^(-5). These anisotropies are believed to originate from primordial density perturbations, caused by quantum fluctuations of scalar fields during the cosmic inflation. In the canonical scenario, the single-field slow-roll inflation, these perturbations are assumed to be sourced by one field, the inflaton. However, it is possible that there are multiple fields present during inflation, that give contribution to the perturbations. In addition to the temperature anisotropies, the CMB spectrum encodes a wealth of information on the thermal history of the early universe. The measured frequency spectrum of the CMB is remarkably close to a black-body spectrum, meaning that the photons and electrons in the early universe plasma were extremely close to a thermal equilibrium. However, in the concordance model of cosmology, Lambda-CDM, there are mechanisms present that lead to unavoidable deviations from the black-body, dubbed as spectral distortions. The diffusion of the acoustic oscillations, that are created due to the initial perturbations, leads to mixing of photons of different temperatures, creating of spectral distortions, which are expected to be below the current observational sensitivity. In the literature, this mechanism is dubbed as the Silk damping. In this thesis we study the formation of mu-type spectral distortions due to the Silk damping in models, where the primordial perturbations are sourced by multiple scalar fields. Our main task is to investigate the spectral distortion signal of inflationary two-field models. We find that generally, the mu-signal can be greatly enhanced compared to the single-field model value. We further show that in a specific two-field model, the mixed inflaton-curvaton model, the mu-distortion testable by future CMB surveys in conjunction with bounds on the tensor-to-scalar ratio r, can efficiently constrain the curvaton model parameter space.
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spellingShingle Leskinen, Juuso Constraining inflationary scalar field models with CMB spectral distortions inflation many field models curvaton primordial perturbations cosmic microwave background spectral distortions mu-distortion Teoreettinen fysiikka Theoretical Physics 4024 fysiikka kosmologia physics cosmology
title Constraining inflationary scalar field models with CMB spectral distortions
title_full Constraining inflationary scalar field models with CMB spectral distortions
title_fullStr Constraining inflationary scalar field models with CMB spectral distortions Constraining inflationary scalar field models with CMB spectral distortions
title_full_unstemmed Constraining inflationary scalar field models with CMB spectral distortions Constraining inflationary scalar field models with CMB spectral distortions
title_short Constraining inflationary scalar field models with CMB spectral distortions
title_sort constraining inflationary scalar field models with cmb spectral distortions
title_txtP Constraining inflationary scalar field models with CMB spectral distortions
topic inflation many field models curvaton primordial perturbations cosmic microwave background spectral distortions mu-distortion Teoreettinen fysiikka Theoretical Physics 4024 fysiikka kosmologia physics cosmology
topic_facet 4024 Teoreettinen fysiikka Theoretical Physics cosmic microwave background cosmology curvaton fysiikka inflation kosmologia many field models mu-distortion physics primordial perturbations spectral distortions
url https://jyx.jyu.fi/handle/123456789/69925 http://www.urn.fi/URN:NBN:fi:jyu-202006154169
work_keys_str_mv AT leskinenjuuso constraininginflationaryscalarfieldmodelswithcmbspectraldistortions