Age problem in the holographic dark energy model

In this paper, we test the original holographic dark energy model with some old high redshift objects. The main idea is very simple: the universe cannot be younger than its constituents. We find that the original holographic dark energy model can be ruled out, unless a lower Hubble constant is taken.

Figure 1

The three solid lines are, from left to right, contours $T_z(3.91)=T_{\mathrm{obj}}(3.91)$, $T_z(1.43)=T_{\mathrm{obj}}(1.43)$, and $T_z(1.55)=T_{\mathrm{obj}}(1.55)$. The WMAP3 bound ${\Omega }_{m0}=0.268\pm 0.018$ [6] is indicated by two short-dashed lines. The model-independent cluster estimate ${\Omega }_{m0}=0.3\pm 0.1$ [67] is indicated by two long-dashed lines. The allowed parameter spaces are the left regions of these contours, as indicated by the arrows. In which, we have used the reduced Hubble constant $h=0.64$.

Figure 2

The same as in Fig. 1, except for $h=0.623$.

Figure 3

The same as in Fig. 1, except for $h=0.56$.