Gravitational waves and gauge fields in the early Universe

Though precise measurements of the cosmic microwave background establish inflation as the leading paradigm of the early Universe, the exact microphysics that realize inflation are poorly constrained. Moreover, inflation generically leaves the Universe cold and empty. The fundamental physics underlying reheating, the dynamics that transition the post-inflationary Universe to a hot Big Bang, are entirely unknown. While uncovering the fundamental physics of the early Universe poses a tremendous theoretical and observational challenge, it also presents an opportunity to study energies far exceeding those that could ever be reproduced experimentally. This thesis explores the role that gravitational wave observations could play in constraining models of the early Universe. We first study the dynamics and signatures of reheating models that lead to the resonant production of Abelian and non-Abelian gauge bosons. We subsequently demonstrate that gravitational wave emission constrains a similar model invoked to resolve the discrepancy in measurements of the present-day expansion rate. Finally, we study gravitational waves induced by scalar metric fluctuations at second order in perturbation theory, performing a detailed study of the imprint of primordial non-Gaussianity on this background.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Physics

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2022

Author dc:creator

• Weiner, Zachary J

Contributors dc:contributor

• Adshead, Peter
• Holder, Gilbert
• Shelton, Jessie
• Filippini, Jeffrey
• Gammie, Charles

• inflation
• gravitational waves
• cosmology
• early Universe
• gauge fields
• reheating
• particle physics
• numerical simulations

Statement dc:rights

• Copyright 2021 Zachary J. Weiner

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/113170

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/113170