# Non-local scalar field on deSitter and its infrared behaviour

## TL;DR

This paper studies non-local scalar fields on deSitter space, showing they have smooth massless limits and no infrared divergences, indicating non-locality may resolve IR problems in deSitter quantum field theory.

## Contribution

It demonstrates that non-local scalar fields on deSitter space have infrared-safe propagators and smooth massless limits, unlike local theories.

## Key findings

- Non-local scalar propagators are free of IR divergences.
- Massless limit of massive propagator is smooth and matches the massless case.
- Non-locality may resolve infrared issues in deSitter space.

## Abstract

We investigate free non-local massless and massive scalar field on deSitter (dS) space-time. We compute the propagator for the non-local scalar field for the corresponding theories on flat and deSitter space-times. It is seen that for the non-local theory, the massless limit of massive propagator is smooth for both flat and deSitter. Moreover, this limit matches exactly with the massless propagator of the non-local scalar field for both flat and deSitter space-time. The propagator is seen to respect dS invariance. Furthermore, investigations of the non-local Green's function on deSitter for large time-like separation shows that the propagator has no infrared divergences. The dangerous infrared $\log$-divergent contributions which arise is local massless theories are absent in the corresponding non-local version. Lack of infrared divergences in the propagator hints at the strong role non-localities may play in the dS infrared physics. This study suggest that non-locality can cure IR issues in deSitter.