Renormalization effects in the early universe

Who: Ole Svendsen (CP3-Origins)
When: Thursday, June 23, 2016

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Ole Svendsen‘s advisor was Francesco Sannino.

Abstract:
In this thesis I address the topic of renormalization effects in the context of early time cosmology. In particular I will focus on the inflationary paradigm and the renormalization group flow of the inflaton field’s potential. Three case studies will be presented: a first look at renor- malization of φ4-inflation, inflation from a pure gravitational theory via the effective field theory approach and a self-consistent, calculable ultraviolet safe quantum field theory.
For the particle field theories I will cover the case of minimal cou- pling to gravity as well as a non-minimal coupling. As will be shown the non-minimally coupled case will be of great interest when renor- malization effects are taken into account. Since in this setup renormal- ization effects are more striking.
In the case where inflation is driven purely by gravity itself, i.e. an extension of the Hilbert-Einstein action, I will motivate marginal deformations to the honored Starobinsky model. Further it will be shown how these deformations can be linked to the particle content above the scale of inflation.
In all three scenarios I will discuss the origins of the theory describ- ing the inflaton field, the inflationary dynamics, and effects on late time cosmological observables, directly linkable to renormalization of the inflaton field’s potential.

The PhD thesis is available as a PDF file.