A Gravitational Mechanism for Cosmological Screening

TL;DR

This paper proposes a gravitational mechanism during inflation where infrared gravitons interact over vast cosmic scales, potentially leading to a natural screening of the universe's accelerated expansion.

Contribution

It introduces a novel gravitational screening mechanism based on infrared graviton interactions that can counteract inflationary acceleration.

Findings

Infrared gravitons contribute significantly to vacuum energy through interactions.

Interactions among gravitons grow over time, affecting cosmic expansion.

The mechanism offers a potential explanation for the end of inflation.

Abstract

Infrared gravitons are continually produced during inflation. Like all particles, their contribution to the vacuum energy comes not only from their bare kinetic energy but also from the interactions they have with other gravitons. These interactions can be substantial -- despite the particles being highly infrared -- because they occur over the enormous spatial volume of the universe. Furthermore, the interactions grow with time evolution because more and more such gravitons come into causal contact with one another. Since gravity is universally attractive, these interactions can act to slow and eventually stop accelerated expansion.