Linear and non-linear perturbations in dark energy models
  In this work we discuss observational aspects of three time-dependent parameterisations of the dark energy equation of state $w(z)$. In order to determine the dynamics associated with these models, we calculate their background evolution and perturbations in a scalar field representation. After performing a complete treatment of linear perturbations, we also show that the non-linear contribution of the selected $w(z)$ parameterisations to the matter power spectra is almost the same for all scales, with no significant difference from the predictions of the standard $\Lambda$CDM model. 
Celia Escamilla-Rivera, Luciano Casarini, Julio C. Fabris and Jailson   S. Alcaniz
astro-ph.CO gr-qc