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arXiv · 1509.05546

Scalar field correlator in de Sitter space at next-to-leading order in a 1/N expansion

Florian Gautier·Julien Serreau
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Abstract

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.

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Florian Gautier, Julien Serreau. 2015-11-21. Scalar field correlator in de Sitter space at next-to-leading order in a 1/N expansion. https://doi.org/10.1103/physrevd.92.105035

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