# Infrared effects in de Sitter spacetime: nonperturbative treatment of secular terms

The study of interacting quantum fields in de Sitter geometry reveals

peculiarities that are of conceptual and phenomenological interest. In

this geometry, the exponential expansion of the metric produces an

effective growth in the self-interaction of light fields, breaking down

the standard perturbative expansion. Furthermore, in the massless limit

the free propagators do not respect the symmetries of the classical

theory, and neither do they decay at large distances.