Cole, Philippa S..pdf (2.87 MB)
Small-scale probes of the early universe
thesis
posted on 2023-06-09, 22:45 authored by Philippa ColeLarge-scale observations of the Cosmic Microwave Background have provided the most substantial evidence for how the Universe expanded rapidly in the first fraction of a second after the Big Bang. This phase of rapid expansion known as inflation provided the seeds for all of the structure that we see in the Universe today, and therefore understanding its dynamics will provide explanations for why the Universe is the way it is, in both the visible and dark sectors. Constraining the dynamics of inflation is best done with the primordial power spectrum, which measures the overdensities and underdensities left over at the end of inflation. This thesis investigates different probes for measuring and constraining the primordial power spectrum on small scales, where constraints are currently much weaker than those deduced from large-scale measurements. The existence or lack of primordial black holes is primarily investigated as a means for both constraining the primordial power spectrum and hence inflation, as well as due to their interest as a dark matter candidate. Large-amplitude scalar perturbations are usually required for the production of primordial black holes, and therefore observational signatures of such perturbations including spectral distortions, stochastic gravitational waves, and the 21cm signal will be explored as means of detecting them. Constraints and signatures from these observations will be compared with classes of inflationary models so as to understand the inflationary dynamics that would be necessary to produce the results and predictions of multiple current and future experiments.
History
File Version
- Published version
Pages
162.0Department affiliated with
- Physics and Astronomy Theses
Qualification level
- doctoral
Qualification name
- phd
Language
- eng
Institution
University of SussexFull text available
- Yes
Legacy Posted Date
2021-01-13Usage metrics
Categories
No categories selectedKeywords
Licence
Exports
RefWorks
BibTeX
Ref. manager
Endnote
DataCite
NLM
DC