Title: Quantum Properties of Inflationary Perturbations

Venue & Time: Red Room / 15:00-16:30

Abstract: This thesis studies quantum aspects of inflationary perturbations beyond tree level, with particular emphasis on loop corrections and renormalization. We develop a practical implementation of dimensional regularization for inflationary in-in calculations, based on separating infrared and ultraviolet contributions and exploiting the universal high-momentum behavior of the mode functions. This allows the ultraviolet renormalization of inflationary observables to be carried out in a largely model-independent way. We apply these methods to the renormalization of scalar and tensor power spectra and of the scalar bispectrum, and investigate which loop corrections represent intrinsically loop-generated physical effects, as opposed to contributions that are degenerate with local counterterms. We also study the limits of classical stochastic descriptions of inflationary fluctuations and the non-Gaussian statistics relevant for primordial black-hole formation.

Supervisor: Guillermo Ballesteros