Sampurnanand, Anjan A Sen
In this work we introduce a new set of parameters (r_{g}, s_{g}) involving the linear growth of matter perturbation that can be used to distinguish different dark energy models. Interestingly for \Lambda CDM model, these parameters take exact values (1,1) at all red shifts whereas for models different from \Lambda CDM, they follow different trajectories in the (r_{g}, s_{g}) phase plane. Using one of the most popular parametrization of dark energy equation of state (CPL parametrization), we show that different dark energy behaviors, with nearly identical evolution of the linear density contrast, can produce distinguishable trajectories in the (r_{g}, s_{g}) phase plane. This shows that these two parameters are powerful tools to distinguish different dark energy models. Finally, using the presently available data for linear growth of structure formation, we show that it is indeed possible to put stringent constraint in the (r_{g}, s_{g}) phase plane ruling out many possible dark energy behaviors.
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http://arxiv.org/abs/1301.0983
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