Super-Hubble de Sitter Fluctuations and the Dynamical RG

TL;DR

This paper applies the Dynamical Renormalization Group to resummation of secular growth in correlation functions of interacting fields in de Sitter space, revealing improved infrared behavior and potential dynamical mass generation.

Contribution

It demonstrates how DRG techniques can effectively resum secular growth in de Sitter correlators, offering new insights into infrared behavior and mass generation.

Findings

Secular growth in correlation functions can be resummed using DRG.

Resummed results show less infrared singularity, indicating dynamical mass.

Comparison with large-N expansion supports the IR improvement.

Abstract

Perturbative corrections to correlation functions for interacting theories in de Sitter spacetime often grow secularly with time, due to the properties of fluctuations on super-Hubble scales. This growth can lead to a breakdown of perturbation theory at late times. We argue that Dynamical Renormalization Group (DRG) techniques provide a convenient framework for interpreting and resumming these secularly growing terms. In the case of a massless scalar field in de Sitter with quartic self-interaction, the resummed result is also less singular in the infrared, in precisely the manner expected if a dynamical mass is generated. We compare this improved infrared behavior with large-N expansions when applicable.