|dc.description.abstract||The aim of this thesis is to investigate the possible implications of quantum anomalies in the early universe. We first consider a new class of natural inflation models based on scale invariance, imposed by the dilaton. In the classical limit, the general scalar potential necessarily contains a flat direction; this is lifted by quantum corrections. The effective potential is found to be linear in the inflaton field, yielding inflationary predictions consistent with observation.
A new mechanism for cogenesis during inflation is presented, in which a new anomalous U(1)_X gauge group in introduced. Anomaly terms source CP and X violating processes during inflation, producing a non-zero CS number density that is distributed into baryonic and dark matter. The two U(1)_X extensions considered in this general framework, gauged B and B-L each containing an additional dark matter candidate, successfully reproduce the observed parameters.
We propose a reheating Baryogenesis scenario that utilises the Ratchet Mechanism. The model contains two scalars that interact via a derivative coupling; an inflaton consistent with the Starobinsky model, and a complex scalar baryon with a symmetric potential. The inflaton-scalar baryon system is found to act analogously to a forced pendulum, with driven motion near the end of reheating generating an \eta_B consistent with observation.
Finally, we argue that a lepton asymmetric CvB develops gravitational instabilities related to the mixed gravity-lepton number anomaly. In the presence of this background, an effective CS term is induced which we investigate through two possible effects. Namely, birefringent propagation of gravitational waves, and the inducement of negative energy graviton modes in the high frequency regime. These lead to constraints on the allowed size of the lepton asymmetry.
These models demonstrate that a concerted approach in cosmology and particle physics is the way forward in exploring the mysteries of our universe.||en_AU|
|dc.publisher||University of Sydney||en_AU|
|dc.publisher||Faculty of Science||en_AU|
|dc.publisher||School of Physics||en_AU|
|dc.rights||The author retains copyright of this thesis. It may only be used for the purposes of research and study. It must not be used for any other purposes and may not be transmitted or shared with others without prior permission.||en_AU|
|dc.subject||Cosmic Neutrins Background||en_AU|
|dc.title||Cosmological Implications of Quantum Anomalies||en_AU|
|dc.type.pubtype||Doctor of Philosophy Ph.D.||en_AU|
|Appears in Collections:||Sydney Digital Theses (Open Access)|