# A solution of the dark energy and its coincidence problem based on local antigravity sources without fine-tuning or new scales

## TL;DR

This paper proposes a natural explanation for dark energy and cosmic coincidence using local antigravity sources linked to astrophysical structures, avoiding fine-tuning and new energy scales.

## Contribution

It introduces a model where local antigravity effects from astrophysical matter explain dark energy without fine-tuning, based on quantum gravity and Swiss cheese cosmology.

## Key findings

- Dark energy explained using Newton's constant and astrophysical scales
- No fine-tuning or new energy scales needed
- Standard cosmological constant interpreted as a composite quantity

## Abstract

A novel idea is proposed for a natural solution of the dark energy and its cosmic coincidence problem. The existence of local antigravity sources, associated with astrophysical matter configurations distributed throughout the universe, can lead to a recent cosmic acceleration effect. Various physical theories can be compatible with this idea, but here, in order to test our proposal, we focus on quantum originated spherically symmetric metrics matched with the cosmological evolution through the simplest Swiss cheese model. In the context of asymptotically safe gravity, we have explained the observed amount of dark energy using Newton's constant, the galaxy or cluster length scales, and dimensionless order one parameters predicted by the theory, without fine-tuning or extra unproven energy scales. The interior modified Schwarzschild-de Sitter metric allows us to approximately interpret this result as that the standard cosmological constant is a composite quantity made of the above parameters, instead of a fundamental one.