was driven by ECHDE. The curvature perturbation may be generated through the curvaton and the only requirement remain as $H \simeq const$ [@wei68a; @wei68b].

Another promising DE candidate is the agegraphic DE and was proposed in [@f49]. Considering the quantum fluctuations of spacetime K$\acute{a}$rolyh$\acute{a}$zy and his collaborators [@f50; @f51; @f52] argued that in Minkowski spacetime any distance $t$ cannot be known to a better accuracy than $\delta t \sim t_p^{\frac{2}{3}}t^{\frac{1}{3}}$, where $t_p$ is the reduced Planck time. Based on the arguments of K$\acute{a}$rolyh$\acute{a}$zy it can be shown that for Minkowski spacetime the energy density of metric fluctuations is given by $\rho_{\Lambda} \sim \frac{m_p^2}{t^2}$ [@f53; @f54]. The agegraphic DE model considers spacetime and matter field fluctuations responsible for DE. If conformal time is considered in place of the age of the universe the model can describe the matter dominated epoch [@f55] with a natural solution to the coincidence problem [@f56] and is known as the new agegraphic DE model. The conformal time $eta$ is defined by $dt = a~d\eta$, where $t$ is the cosmic time and $a$ the scale factor. Many authors did some detailed study of this new agegraphic DE model [@f57; @f58; @f59; @f60].

Also we have other possible 