$Om$ Diagnostic for Dilaton Dark Energy

TL;DR

This paper applies the $Om$ diagnostic to the dilaton dark energy model to distinguish it from LCDM and examines how the coupling parameter affects its evolution, finding a current equation of state consistent with observational data.

Contribution

The study introduces the use of the $Om$ diagnostic specifically for the dilaton dark energy model and analyzes the impact of the coupling parameter on its evolution.

Findings

The current equation of state parameter $\omega_{\sigma0}$ is approximately -0.952.

The $Om$ diagnostic effectively differentiates DDE from LCDM.

The coupling parameter $\alpha$ influences the evolution of $Om$ with redshift.

Abstract

$Om$ diagnostic can differentiate between different models of dark energy without the accurate current value of matter density. We apply this geometric diagnostic to dilaton dark energy(DDE) model and differentiate DDE model from LCDM. We also investigate the influence of coupled parameter $\alpha$ on the evolutive behavior of $Om$ with respect to redshift $z$. According to the numerical result of $Om$, we get the current value of equation of state $\omega_{\sigma0}$=-0.952 which fits the WMAP5+BAO+SN very well.