Massless Interacting Scalar Fields in de Sitter space

Abstract

We present a method to compute the two-point functions for an $O(N)$ scalar field model in de Sitter spacetime, avoiding the well known infrared problems for massless fields. The method is based on an exact treatment of the Euclidean zero modes and a perturbative one of the nonzero modes, and involves a partial resummation of the leading secular terms. This resummation, crucial to obtain a decay of the correlation functions, is implemented along with a double expansion in an effective coupling constant $\sqrt{\lambda }$ and in $1/N$. The results reduce to those known in the leading infrared approximation and coincide with the ones obtained directly in Lorentzian de Sitter spacetime in the large $N$ limit. The new method allows for a systematic calculation of higher order corrections both in $\sqrt{\lambda }$ and in $1/N$.

8 pages. Summarized version of JHEP 09 (2016) 117 [arXiv:1606.03481]. Published in the Proceedings of the 19th International Seminar on High Energy Physics (QUARKS-2016)

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Cited by in corpus (6)

• Characters of different secular effects in various patches of de Sitter space
• Infrared dynamics of massive scalars from the complementary series in de Sitter space
• To the sphere and back again: de Sitter infrared correlators at NTLO in 1/N
• A quantum heating as an alternative of reheating
• Quantum backreaction of $O(N)$-symmetric scalar fields and de Sitter spacetimes at the renormalization point: renormalization schemes and the screening of the cosmological constant
• RG flows in de Sitter: c-functions and sum rules