Statefinder parameters for quantum effective Yang-Mills condensate dark energy model

Abstract

The quantum effective Yang-Mills condensate (YMC) dark energy model has some distinguished features that it naturally solves the coincidence problem and, at the same time, is able to give an equation of state $w$ crossing -1. In this work we further employ the Statefinder pair $(r,s)$ introduced by Sahni et al to diagnose the YMC model for three cases: the non-coupling, the YMC decaying into matter only, and the YMC decaying into both matter and radiation. The trajectories $(r,s)$ and $(r,q)$, and the evolutions $r(z)$, $s(z)$ are explicitly presented. It is found that, the YMC model in all three cases has $r\simeq 1$ for $ z < 10$ and $s\simeq 0$ for $z<5$ with only small deviations $\simeq 0.02$, quite close to the cosmological constant model (LCDM), but is obviously differentiated from other dark energy models, such as quiesence, kinessence etc.