Dark energy and matter interacting scenario to relieve $H_0$ and $S_8$ tensions

TL;DR

This study introduces a new interacting dark energy model that, when combined with specific observational data, significantly reduces the tensions in Hubble constant and matter fluctuation amplitude measurements, outperforming the standard Lambda-CDM model.

Contribution

The paper proposes a novel interacting vacuum energy model that better alleviates H_0 and S_8 tensions compared to Lambda-CDM, especially when combined with additional observational data.

Findings

Relieves H_0 tension to 0.72σ with combined data.

Relieves S_8 tension to 2.11σ with combined data.

Model is most favored when H_0 and S_8 data are included.

Abstract

We consider a new cosmological model (called $\tilde\Lambda$CDM) in which the vacuum energy interacts with matter and radiation, and test this model using the current cosmological observations. Using the CMB+BAO+SN (CBS) dataset to constrain the model, we find that $H_0$ and $S_8$ tensions are relieved to $2.87\sigma$ and $2.77\sigma$, respectively. However, in this case, the $\tilde\Lambda$CDM model is not favored by the data, compared with $\Lambda$CDM. We find that when the $H_0$ and $S_8$ data are added to the data combination, the situation is significantly improved. In the CBS+$H_0$ case, the model relieves the $H_0$ tension to $0.47\sigma$, and the model is favored over $\Lambda$CDM. In the CBS+$H_0$+$S_8$ case, we obtain a synthetically best situation, in which the $H_0$ and $S_8$ tensions are relieved to $0.72\sigma$ and $2.11\sigma$, respectively. In this case, the model is most favored by the data. Therefore, this cosmological model can greatly relieve the $H_0$ tension and simultaneously effectively alleviate the $S_8$ tension.