2015/09/30 by Florian Gautier, Julien Serreau · 1 citation
Physics and Astronomy · #hep-th #gr-qc #hep-ph #nucl-th
paper · pdf · doi:10.1103/physrevd.92.105035
published as Phys. Rev. D 92, 105035 (2015) · 14 pages, 5 figures, published version (Phys. Rev. D)
arxiv created 2015/11/21 · arxiv updated 2015/12/09
We study the dynamics of light quantum scalar fields in de Sitter space on superhorizon scales. We compute the self-energy of an O(N) symmetric theory at next-to-leading order in a 1/N expansion in the regime of superhorizon momenta, and we obtain an exact analytical solution of the corresponding Dyson-Schwinger equations for the two-point correlator. This amounts to resumming the infinite series of nonlocal self-energy insertions, which typically generate spurious infrared and/or secular divergences. The potentially large de Sitter logarithms resum into well-behaved power laws from which we extract the field strength and mass renormalization. The nonperturbative 1/N expansion allows us to discuss the case of vanishing and negative tree-level square mass, which both correspond to strongly coupled effective theories in the infrared.