Can the Chaplygin gas be a plausible model for dark energy?

Abstract

In this paper two cosmological models representing the flat Friedmann universe filled with a Chaplygin fluid, with or without dust, are analyzed in terms of the recently proposed ``statefinder'' parameters. Trajectories of both models in the parameter plane are shown to be significantly different with respect to the ``quiessence'' and ``tracker'' models. The generalized Chaplygin gas model with an equation of state of the form $p=\ensuremath{-}A/{\ensuremath{\rho}}^{\ensuremath{\alpha}}$ is also analyzed in terms of the statefinder parameters.