Infrared effects in inflationary correlation functions

Abstract this article, I briefly review the status of infrared effects which occur when using inflationary models to calculate initial conditions for a subsequent hot, dense plasma phase. Three types of divergence have been identified in the literature: secular, " time-dependent " logarithms, which grow with time spent outside the horizon ; " box-cutoff " logarithms, which encode a dependence on the infrared cutoff when calculating in a finite-size box ; and " quantum " logarithms, which depend on the ratio of a scale characterizing new physics to the scale of whatever process is under consideration, and whose interpretation is the same as conventional field theory. I review the calculations in which these divergences appear, and discuss the methods which have been developed to deal with them., Physics of the early universe, Quantum field theory in curved spacetime.