Infrared effects in de Sitter QFT: Non-perturbative treatments

TROMBETTA LEONARDO GIULIANO

Trieste

Congreso; First ICTP Advanced School on Cosmology; 2015

ICTP

The calculation of correlation functions for the inflaton in de Sitter spacetime is plagued with infrared problems when the field is very light, or massless. This effects can be better understood by treating the interactions non perturbatively, which leads to a dynamically genereated mass that regulates the divergences. Three non perturbative approaches are considered, namely, stochastic inflation, the 2PI effective action and euclidean de Sitter space. Although the leading order results in the infrared limit agree among these methods, the equivalence between them is still a matter of debate.