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63 - Z. G. Huang , H. Q. Lu 2010
$Om$ 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 invest igate 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.
307 - Z. G. Huang , H. Q. Lu , W. Fang 2009
Applying the parametrization of dark energy density, we can construct directly independent-model potentials. In Born-Infeld type phantom dark energy model, we consider four special parametrization equation of state parameter. The evolutive behavior o f dark energy density with respect to red-shift $z$, potentials with respect to $phi$ and $z$ are shown mathematically. Moreover, we investigate the effect of parameter $eta$ upon the evolution of the constructed potential with respect to $z$. These results show that the evolutive behavior of constructed Born-Infeld type dark energy model is quite different from those of the other models.
Statefinder diagnostic is a useful method which can differ one dark energy model from the others. The Statefinder pair ${r, s}$ is algebraically related to the equation of state of dark energy and its first time derivative. We apply in this paper thi s method to the dilaton dark energy model based on Weyl-Scaled induced gravitational theory. We investigate the effect of the coupling between matter and dilaton when the potential of dilaton field is taken as the Mexican hat form. We find that the evolving trajectory of our model in the $r-s$ diagram is quite different from those of other dark energy models.
63 - Z. G. Huang , H. Q. Lu 2008
Using a new method--statefinder diagnostic which can differ one dark energy model from the others, we investigate in this letter the dynamics of Born-Infeld(B-I) type dark energy model. The evolutive trajectory of B-I type dark energy with Mexican ha t potential model with respect to $e-folding$ time $N$ is shown in the $r(s)$ diagram. When the parameter of noncanonical kinetic energy term $etato0$ or kinetic energy $dot{phi}^2to0$, B-I type dark energy(K-essence) model reduces to Quintessence model or $Lambda$CDM model corresponding to the statefinder pair ${r, s}$=${1, 0}$ respectively. As a result, the the evolutive trajectory of our model in the $r(s)$ diagram in Mexican hat potential is quite different from those of other dark energy models.
72 - Z. G. Huang , Q. Q. Sun , W. Fang 2006
In this paper, we regard dilaton in Weyl-scaled induced gravitational theory as coupled Quintessence, which is called DCQ model by us. Parametrization of the dark energy model is a good method by which we can construct the scalar potential directly f rom the effective equation of state function $omega_sigma(z)$ describing the properties of the dark energy. Applying this method to the DCQ model, we consider four parametrizations of $omega(z)$ and investigate the features of the constructed DCQ potentials, which possess two different evolutive behaviors called O mode and E mode. Lastly, we comprise the results of the constructed DCQ model with those of quintessence model numerically.
In this paper, we investigate the dynamics of Born-Infeld(B-I) phantom model in the $omega-omega$ plane, which is defined by the equation of state parameter for the dark energy and its derivative with respect to $N$(the logarithm of the scale factor $a$). We find the scalar field equation of motion in $omega-omega$ plane, and show mathematically the property of attractor solutions which correspond to $omega_phisim-1$, $Omega_phi=1$, which avoid the Big rip problem and meets the current observations well.
125 - Z. G. Huang , H. Q. Lu , W. Fang 2006
In this paper, we regard dilaton in Weyl-scaled induced gravitational theory as a coupled quintessence. Based on this consideration, we investigate the dilaton coupled quintessence(DCQ) model in $omega-omega$ plane, which is defined by the equation o f state parameter for the dark energy and its derivative with respect to $N$(the logarithm of the scale factor $a$). We find the scalar field equation of motion in $omega-omega$ plane, and show mathematically the property of attractor solutions which correspond to $omega_sigmasim-1$, $Omega_sigma=1$. Finally, we find that our model is a tracking one which belongs to freezing type model classified in $omega-omega$ plane.
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