Speaker
Description
In this talk, we examine some of the challenges that can arise when renormalizing UV divergences in cosmological settings. One fundamental step of renormalization is regularization. Hence, we start by introducing two of the most commonly used regularization schemes: hard cutoffs and dimensional regularization. Specifically, we demonstrate that in the case of finite inflationary background evolution, physical ``preferred" scales corresponding to the beginning and end of inflation do not regulate UV divergences. We show that dimensional regularization can be used to regulate these UV divergences, and is, in general, preferable to hard cutoffs, since it allows divergences to be absorbed by counterterms that preserve the symmetries of the background. Furthermore, we discuss how the potential errors can arise when UV divergences are not carefully managed, focusing on the example of the energy density of primordial vacuum gravitational waves,
This talk is based on: AN and S. P. Patil, Riv.Nuovo Cim. 47 (2024) 3, 179-228
