Scalar field descriptions of two dark energy models

Abstract

We give a scalar field description of two dark energy parameterizations, and we analyze in detail its cosmology both at the level of background evolution and at the level of linear perturbations. In particular, we compute the statefinder parameters and the growth index as functions of the red-shift for both dark energy parameterizations, and the comparison with the $\Lambda CDM$ model as well as with a few well-known geometrical dark energy models is shown. In addition, the combination parameter $A=f \sigma_8$ of both models is compared against current data.