Swiss-cheese cosmologies with variable $G$ and $\Lambda$ from the renormalization group

TL;DR

This paper extends RG-improved swiss-cheese cosmologies to include variable G and Lambda, demonstrating they can naturally explain cosmic acceleration and align with observational constraints without fine-tuning.

Contribution

It introduces a model with combined G and Lambda scaling based on IR-fixed point hypothesis, matching Lambda CDM and satisfying local G variation constraints.

Findings

Model reproduces observed cosmic acceleration without exotic fields.

Both scaling relations agree well with Lambda CDM cosmology.

Model satisfies local observational constraints on G variation.

Abstract

A convincing explanation for the nature of the dark energy and dark matter is still missing. In recent works a RG-improved swiss-cheese cosmology with an evolving cosmological constant dependent on the \sch radius has been proven to be a promising model to explain the observed cosmic acceleration. In this work we extend this model to consider the combined scaling of the Newton constant $G$ and the cosmological constant $\Lambda$ according to the IR-fixed point hypothesis. We shall show that our model easily generates the observed recent passage from deceleration to acceleration without need of extra energy scales, exotic fields or fine tuning. In order to check the generality of the concept, two different scaling relations have been analysed and we proved that both are in very good agreement with $\Lambda$CDM cosmology. We also show that our model satisfies the observational local constraints on $\dot{G}/G$.