Nonlocal Cosmology

TL;DR

This paper investigates nonlocal gravity models inspired by quantum corrections as a way to explain cosmic acceleration, highlighting their delayed response, reduced fine-tuning, and negligible solar system effects.

Contribution

It introduces nonlocal gravity models that naturally incorporate large time scales, offering a novel approach to cosmic acceleration without fine-tuning.

Findings

Models explain cosmic acceleration without fine-tuning

Solar system effects are negligible

Potential implications for black hole information problem

Abstract

We explore nonlocally modified models of gravity, inspired by quantum loop corrections, as a mechanism for explaining current cosmic acceleration. These theories enjoy two major advantages: they allow a delayed response to cosmic events, here the transition from radiation to matter dominance, and they avoid the usual level of fine tuning; instead, emulating Dirac's dictum, the required large numbers come from the large time scales involved. Their solar system effects are safely negligible, and they may even prove useful to the black hole information problem.