Cosmic age problem in holographic and ghost dark energy models

In this paper, we study the cosmic age problem in holographic (HDE) and generalized ghost dark energy (GGDE) models. To this end, we consider these two models in presence of non-linear interaction terms for three special cases, presented in the literature. We explain the impacts of the mentioned interaction terms on the cosmic age during the evolution of the Universe. There are many old cosmic objects (OCOs) which their evaluated age is not consistent with that of dark energy models. Here, we confine our attention on five cases of more known OCOs at different redshift. The purpose is to constrain the DE models, using the age of these OCOs. We obtain boundary values for free parameters of the HDE (b(2) and c) using the age test and find that, such non-linear interactions can alleviate the age problem in spite of the linear one. The GGDE was already constrained using a joint analysis of data sets SHBC. We find a new bound for xi that wasn't predicted via SHBC analysis. Beside, we find that the GGDE can completely alleviate the cosmic age problem.

Automated summary

This paper studies the cosmic age problem in holographic and generalized ghost dark energy models, and finds that non-linear interactions can alleviate the age problem. By analyzing age tests and data sets, the study also discovers a new bound for a parameter and shows that the generalized ghost dark energy can completely alleviate the cosmic age problem.