Models and probes of the early and dark Universe : inflation and 21-cm radiation in cosmology
department or school: Science, Faculty of
department or school: Physics and Astronomy, Department of
data provider: DSpace
degree campus: UBCV
creator: Sitwell, Michael
issued: 2014-11-19T15:44:20Z
issued: 2014
related degree: Doctor of Philosophy - PhD
degree grantor: University of British Columbia
description: The prevailing model of modern cosmology stipulates the existence of exotic substances such as dark matter and dark energy and events such as inflation. However, their underlying nature is not currently known. In this thesis, we explore new models and measurement techniques that may be used to characterize their cosmological effects and shed light on their inner workings. A model of inflation driven by a substance that may be described macroscopically as a cosmological elastic solid is studied. The proper techniques for the quantization of perturbations within the elastic solid are presented. We find that a sufficiently rigid elastic solid with slowly varying sound speeds can produce an inflationary period. Interestingly, we find models where the elastic solid has an equation of state significantly greater than -1 that nevertheless produces nearly scale-invariant scalar and tensor spectra. The remaining chapters of this thesis concern the use of 21-cm radiation as a probe of the physics of dark matter and dark energy. The effects of warm dark matter on the highly-redshifted 21-cm signal is examined. If dark matter is warm instead of cold, its non-negligible velocities may inhibit the formation of low-mass halos, thereby delaying star-formation, which may delay the emission and absorption signals expected in the mean 21-cm signal. The effects of warm dark matter on both the mean 21-cm signal, as well as on its power spectrum, are described and degeneracies between the effects of warm dark matter and other astrophysical parameters are quantified. One of the primary goals of 21-cm radiation intensity mapping is to measure baryon acoustic oscillations over a wide range of redshifts to constrain the properties of dark energy from the expansion history of the late-time Universe. We forecast the constraining power of the CHIME radio telescope on the matter power spectrum and dark energy parameters. Lastly, we devise new calibration algorithms for the gains of an interferom…
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/51117
note: Models and Probes of the Early andDark UniverseInflation and 21-cm Radiation in CosmologybyMichael SitwellB.Sc., Queen’s University, 2008A THESIS SUBMITTED IN PARTIAL FULFILLMENT OFTHE REQUIREMENTS FOR THE DEGREE OFDOCTOR OF PHILOSOPHYinThe Faculty of Graduate and Postdoctoral Studies(Physics)THE UNIVERSITY OF BRITISH COLUMBIA(Vancouver)November 2014c Michael Sitwell 2014AbstractThe prevailing model of modern cosmology stipulates the existence of exoticsubstances such as dark matter and dark energy and events such as inflation.However, their underlying nature is not currently known. In this thesis,we explore new models and measurement techniques that may be used tocharacterize their cosmological e↵ects and shed light on their inner workings.A model of inflation driven by a substance that may be described macro-scopically as a cosmological elastic solid is studied. The proper techniquesfor the quantization of perturbations within the elastic solid are presented.We find that a suciently rigid elastic solid with slowly varying sound speedscan produce an inflationary period. Interestingly, we find models where theelastic solid has an equation of state significantly greater than 1 that nev-ertheless produces nearly scale-invariant scalar and tensor spectra.The remaining chapters of this thesis concern the use of 21-cm radiationas a probe of the physics of dark matter and dark energy.The e↵ects of warm dark matter on the highly-redshifted 21-cm signalis examined. If dark matter is warm instead of cold, its non-negligible ve-locities may inhibit the formation of low-mass halos, thereby delaying star-formation, which may delay the emission and absorption signals expectedin the mean 21-cm signal. The e↵ects of warm dark matter on both themean 21-cm signal, as well as on its power spectrum, are described and de-generacies between the e↵ects of warm dark matter and other astrophysicalparameters are quantified.One of the primary goals of 21-cm radiation intensity mapping is to …
has type: Thesis/Dissertation
date issued: 2015-02
is shown at: 10.14288/1.0167036
language: eng
degree discipline: Physics
provider: Vancouver : University of British Columbia Library
publisher: University of British Columbia
rights: Attribution-NonCommercial-NoDerivs 2.5 Canada
rights URI: http://creativecommons.org/licenses/by-nc-nd/2.5/ca/
scholar level: Graduate
type: Text
identifier URI: http://hdl.handle.net/2429/51117