2013/05/31 by Florian Gautier, Julien Serreau · 1 citation
Physics and Astronomy · #gr-qc #hep-ph #hep-th #nucl-th
paper · pdf · doi:10.1016/j.physletb.2013.10.072
9 pages, 3 figures, published version, some material has been added, title changed
arxiv created 2013/11/09 · arxiv updated 2015/06/16
We study the two-point correlator of an O(N) scalar field with quartic self-coupling in de Sitter space. For light fields in units of the expansion rate, perturbation theory is plagued by large logarithmic terms for superhorizon momenta. We show that a proper treatment of the infinite series of self-energy insertions through the Schwinger-Dyson equations resums these infrared logarithms into well defined power laws. We provide an exact analytical solution of the Schwinger-Dyson equations for infrared momenta when the self-energy is computed at two-loop order. The obtained correlator exhibits a rich structure with a superposition of free-field-like power laws. We extract mass and field-strength renormalization factors from the asymptotic infrared behavior. The latter are nonperturbative in the coupling in the case of a vanishing tree-level mass.