Decaying Lambda cosmology with varying G

TL;DR

This paper explores a cosmological model with decaying vacuum energy and a time-varying gravitational constant, demonstrating compatibility with observed cosmological parameters without fine-tuning.

Contribution

It introduces a cosmological model combining decaying vacuum energy and variable G, aligning with observations and eliminating the need for fine-tuning.

Findings

Consistent with observed cosmological parameters at late times

Achieves observed matter-to-total energy density ratio without fine-tuning

Supports viability of variable G and decaying vacuum energy in cosmology

Abstract

We study a uniform and isotropic cosmology with a decaying vacuum energy density, in the realm of a model with a time varying gravitational "constant". We show that, for late times, such a cosmology is in accordance with the observed values of the cosmological parameters. In particular, we can obtain the observed ratio between the matter density and the total energy density, with no necessity of any fine tuning.