Cosmological perturbations in mimetic matter model
  We investigate the cosmological evolution of mimetic matter model with
arbitrary scalar potential. The cosmological reconstruction, which is the way
to construct a model for arbitrary evolutions of the scale factor, is
explicitly done for different choices of potential. The cases that mimetic
matter model shows the evolution as Cold Dark Matter(CDM), wCDM model, dark
matter and dark energy with dynamical $Om(z)$, where $Om(z) \equiv [
(H(z)/H_0)^2-1 ]/[(1+z)^3 -1],$ or phantom dark energy with phantom-non-phantom
crossing are presented in detail. The cosmological perturbations for such
evolution are studied in mimetic matter model. For instance, the evolution
behavior of the matter density contrast which is different from usual one, i.e.
$\ddot \delta + 2 H \dot \delta - \kappa ^2 \rho \delta /2 = 0$ is
investigated. The possibility of peculiar evolution of $\delta$ in the model
under consideration is shown. Special attention is paid to the behavior of
matter density contrast near to future singularity where decay of perturbations
may occur much earlier the singularity.
