Stability of de Sitter spacetime against infrared quantum scalar field fluctuations

TL;DR

This paper investigates how quantum scalar field fluctuations influence de Sitter spacetime stability, using nonperturbative renormalization group techniques to show that infrared effects are screened, leading to a stable geometry.

Contribution

It introduces a nonperturbative approach via Wilsonian renormalization group to analyze infrared quantum effects on de Sitter spacetime stability.

Findings

Infrared quantum fluctuations are screened by nonperturbative effects.

The spacetime curvature remains stable despite quantum fluctuations.

Loop corrections in the infrared do not destabilize de Sitter space.

Abstract

We study the backreaction of superhorizon fluctuations of a light quantum scalar field on a classical de Sitter geometry by means of the Wilsonian renormalisation group. This allows us to treat the gravitationally amplified fluctuations in a nonperturbative manner and to analytically follow the induced renormalisation flow of the spacetime curvature as long wavelength modes are progressively integrated out. Unbounded loop corrections in the deep infrared are eventually screened by nonperturbative effects which stabilise the geometry.