Can decaying vacuum elucidate the late-time dynamics of the Universe ?

TL;DR

This study investigates a decaying vacuum energy model with a small decay rate parameter, constrained by multiple cosmological observations, suggesting it can address the Hubble tension and behaves like quintessence.

Contribution

The paper constrains the decaying vacuum model using diverse observational data, showing it can alleviate the Hubble tension and exhibits quintessence-like behavior.

Findings

Decay rate parameter epsilon is approximately -0.0003.

Hubble constant H0 is about 68.05 km/s/Mpc, reducing the H0 tension.

Model behaves like quintessence, with a slightly better fit than LambdaCDM.

Abstract

We examine the decay vacuum model with a parameter $\epsilon$ that indicates the vacuum energy decay rate. By constraining this model with cosmic microwave background radiation, baryon acoustic oscillation, type Ia supernovae and 30 H(z) cosmic chronometer data points, we find that $\epsilon=-0.0003\pm0.00024$ with the best fitted $\chi^{2}$ value slightly smaller than that in the $\Lambda$CDM model. A negative value of $\epsilon$ suggesting dark matter energy decay into vacuum energy. We also obtain the Hubble constant $H_{0}=68.05\pm0.56$ that can alleviate the current $H_{0}$ tension between the local observation by the Hubble Space Telescope and the global measurement by the Planck Satellite. Using the effective equation of state formalism, we find this model is quintessence-like.