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arXiv · 2507.21224

Resummation of Cosmological Correlators and their UV-Regularization

Matthias Nowinski·Ivo Sachs
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Abstract

Cosmological correlators are important observables in cosmology. They are often approximated by de Sitter space correlators. In this paper, we give a first precise diagrammatical computation of higher loop diagrams to all orders for a conformally coupled scalar in four dimensions. We show that, in contrast to flat space, diagrams of necklace topology do not resum using the natural application of de Sitter-invariant regularization and are thus hard to evaluate. We propose a modification to the UV-regularization of the loops, compatible with de Sitter invariance, but much easier to work with. The modified diagrams can be resummed to give a glimpse at non-perturbative effects for de Sitter correlators. Furthermore, they fit nicely with recently proposed cosmological dressing rules.

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Matthias Nowinski, Ivo Sachs. 2025-07-28. Resummation of Cosmological Correlators and their UV-Regularization. https://arxiv.org/abs/2507.21224

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