To the sphere and back again: de Sitter Infrared correlators at NTLO in 1/N

DIANA L. LÓPEZ NACIR

Valdivia

Conferencia; VIII Quantum Gravity in the Southern Cone; 2019

https://fisica.cab.cnea.gov.ar/QGSC-VIII/index.php

The analysis of the infrared (IR) behavior of correlation functions for interacting fields in de Sitter (dS) spacetime is of high interest in the context of semiclassical and quantum gravity.It has been shown that the loop expansion breaks down at large dS-invariant distances for light fields, due to seculary growing corrections. In this talk I will focus on the IR behavior of the two-point functions for a massless O(N) model in Lorentzian dS spacetime, using the 1/N expansion.Our approach is based on the study of the Schwinger-Dyson equations on the sphere (Euclidean dS space), using the fact that the infrared behavior in the Lorentzian spacetime is determined by the pole structure of the Euclidean correlation functions. While equivalent to other approaches, our procedure turns out to be considerably simpler.