PIRSA:25090043

Video URL

https://pirsa.org/25090043

The infrared story of light scalars in de Sitter

(2025). The infrared story of light scalars in de Sitter. Perimeter Institute for Theoretical Physics. https://pirsa.org/25090043

The infrared story of light scalars in de Sitter. Perimeter Institute for Theoretical Physics, Sep. 09, 2025, https://pirsa.org/25090043 

          @misc{ scivideos_PIRSA:25090043,
            doi = {10.48660/25090043},
            url = {https://pirsa.org/25090043},
            author = {},
            keywords = {Cosmology},
            language = {en},
            title = {The infrared story of light scalars in de Sitter},
            publisher = {Perimeter Institute for Theoretical Physics},
            year = {2025},
            month = {sep},
            note = {PIRSA:25090043 see, \url{https://scivideos.org/pirsa/25090043}}
          }
Nadine Nussbaumer
Talk numberPIRSA:25090043
DOI10.48660/25090043
Source RepositoryPIRSA
Collection
Talk Type Scientific Series
Subject

Abstract

Perturbative calculations with light and polynomially self-interacting scalar fields in de Sitter spacetime are commonly plagued by infrared divergences as the scalar fluctuations become strongly coupled on large scales. Using techniques familiar from stochastic inflation, we treat super-Hubble fluctuations non-perturbatively through a probability distribution featuring composite operators of the light scalar. We find that these composite operators behave like late-time conformal primaries and admit a power-law four-point function in position space that is strikingly simple. We attribute physical meaning to these composite operators and conjecture that light interacting scalars in de Sitter in the stochastic picture hadronize into a tower of composite scalars on superhorizon scales. We further investigate whether these composite scalars can be described by a weakly-coupled effective field theory.