Statefinder diagnostic for the modified polytropic Cardassian universe

Abstract

We apply the Statefinder diagnostic to the Modified Polytropic Cardassian Universe in this work. We find that the Statefinder diagnostic is quite effective to distinguish Cardassian models from a series of other cosmological models. The $s-r$ plane is used to classify the Modified Polytropic Cardassian models into six cases. The evolutionary trajectories in the $s-r$ plane for the cases with different $n$ and $\beta$ reveal different evolutionary properties of the universe. In addition, we combine the observational $H(z)$ data, the Cosmic Microwave Background (CMB) data and the Baryonic Acoustic Oscillation (BAO) data to make a joint analysis. We find that \textbf{Case 2} can be excluded at the 68.3% confidence level and any case is consistent with the observations at the 95.4% confidence level.Comment: Comments: Final version for publication in Physical Review D [minor revision to match the appear version] Journal-ref: Physical Review D 75, 083515 (2007

Latest observational constraints on Cardassian models

“…1 and is consistent with the ΛCDM cosmology ( [40], Ω m0 = 0.25 +0.04 −0.04 ). We find that combining these observational data can tighten the constraints significantly comparing to the results from former academic papers [22,33,48,49] With these data using in this paper, we can determine when the universe acceleration began in Cardassian models by investigating the deceleration parameter q(z). As shown in Fig.…”

“…As we know, many observational constraints have been placed on Cardassian models, including those from the angular size of high-z compact radio sources [21], the SNe Ia [22,23,24,25,26,27,28,29,30,31,32], the shift parameter of the CMB [23,28,32,33], the baryon acoustic peak from the SDSS [23,33], the gravitational lensing [34], the x-ray gas mass fraction of clusters [29,35], the large scale structure [32,36,37], and the Hubble parameter versus redshift data [33,38].…”

Latest cosmological constraints on Cardassian expansion models including the updated gamma-ray bursts

“…Up to now, the Cardassian model have been constrained from many observational data, such as the angular size of the compact radio sources (Zhu & Fujimoto 2002), SNe Ia (Wang et al 2003;Zhu & Fujimoto 2003;Szydlowski & Czaja 2004;Godlowski et al 2004;Frith 2004;Bento et al 2005), the x-ray gas mass fraction of clusters (Zhu & Fujimoto 2004;Zhu et al 2004), CMB (Sen & Sen 2003;Savage et al 2005), the large scale structure (Multamaki et al 2003;Amarzguioui et al 2005;Fay & Amarzguioui 2006), the gravitational lensing (Alcaniz et al 2005), the baryonic acoustic oscillation (BAO) ), the Hubble parameter versus redshift data (Yi & Zhang 2007), as well as the different combined data (Bento et al 2006;Davis et al 2007;Wang & Wu 2009;Feng & Li 2010). Also, constraints from GRBs with the joint analysis on the Cardassian model can be obtained in Cuesta et al 2008a;Wang et al 2009a;Wang & Liang 2010).…”

Statefinder Diagnostic in Generalized Chaplygin Gas Model with and Without Viscosity

“…The statefinder pair has been used to explore a series of dark energy and cosmological models [31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46]. As is analyzed, the "distance" from a given dark energy model to the LCDM scenario can be clearly identified via the r(s) evolution diagram.…”