Leiden University Scholarly Publications

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Iarygina, O. (2021)

Enlightening the primordial dark ages

Doctoral Thesis
This thesis is dedicated to the exploration of the primordial dark ages: unknown physics during the earliest stages of the Universe’s expansion that have not yet been directly probed by observations. Cosmic inflation is a burst of exponential expansion of space after the “Big Bang”. The energy that drives inflation must be transferred to elementary particles and radiation. This process is called reheating. The unknown expansion history of the universe during the reheating era connects the cosmic microwave background (CMB) observations to inflationary physics. CMB is a relic radiation that provides us a snapshot of the primordial universe. Both the inflationary and reheating eras generate signatures to be seen via upcoming gravitational waves and CMB polarization experiments. In this thesis we show analytically a scaling behaviour that allows for an easy estimate of the reheating efficiency for one broad family of multi-field models of inflation that is called α-attractors. We show...Show moreThis thesis is dedicated to the exploration of the primordial dark ages: unknown physics during the earliest stages of the Universe’s expansion that have not yet been directly probed by observations. Cosmic inflation is a burst of exponential expansion of space after the “Big Bang”. The energy that drives inflation must be transferred to elementary particles and radiation. This process is called reheating. The unknown expansion history of the universe during the reheating era connects the cosmic microwave background (CMB) observations to inflationary physics. CMB is a relic radiation that provides us a snapshot of the primordial universe. Both the inflationary and reheating eras generate signatures to be seen via upcoming gravitational waves and CMB polarization experiments. In this thesis we show analytically a scaling behaviour that allows for an easy estimate of the reheating efficiency for one broad family of multi-field models of inflation that is called α-attractors. We show the influence of the asymmetry around the minimum of potential on the reheating efficiency. Moreover, we study the predictions for chiral gravitational waves production by a spectator gauge field sector in scalar single-field inflation. Finally, we present a new class of inflationary models that is called “shift-symmetric orbital inflation”.
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Cosmology
Physics of the early universe
Cosmic inflation
Reheating
Primordial gravitational waves
Cosmological perturbation theory
Primordial power spectrum
Multi-field inflation
Effective field theory
Theoretical high energy physics
All authors
Iarygina, O.
Supervisor
Achúcarro, A.
Co-supervisor
Sfakianakis, E.I.
Committee
Copeland, E.J.; Vilchinskiy, S.I.; Bezrukov, F.; Maleknejad, A.; Aarts, J.; Schalm, K.E.
Qualification
Doctor (dr.)
Awarding Institution
Leiden Institute of Physics (LION), Faculty of Science, Leiden University
Date
2021-11-03
Title of host publication
Casimir PhD Series
ISBN (print)
9789085934950

Publication Series

Name
2021-29

Funding

Sponsorship
The work in this thesis is funded by the Gravity program of the Netherlands Or- ganization for Scientific Research (NWO) and the Ministry of Education, Culture and Science (OCW).