A new type of interaction between generalized Chaplygin gas and dark matter

Abstract

In this paper, we investigate the model with a new type of interaction between generalized Chaplygin gas (GCG) and dark matter. It is shown that there exists a stable scaling attractor, which provides the possibility to alleviate the coincidence problem. The equation of state (EoS) of GCG approaches the attractor phase from either w g > −1 or w g < −1 depending on the choice of its initial cosmic density parameter and the ratio of pressure to critical energy density. For initial choice of w g < −1, our new model allows the universe to cross the phantom divide (the transition from w g < −1 to w g > −1), and next cross again the phantom divide (the transition from w g > −1 to w g < −1), finally reach the attractor phase. We also find the new interacting term Q can change its sign from Q < 0 to Q > 0 as the universe expands, which is different from the usual interaction. Moreover, we investigate the model from statefinder viewpoint. The statefinder diagnostic can not only discriminate the model with different coupling constant but also distinguish the model from other dark energy models.

FRW bulk viscous cosmology with modified Chaplygin gas in flat space

“…where we assumed c = 1 and 8πG = 1. Also the energymomentum tensor corresponding to the bulk viscous fluid and modified Chaplygin gas (Benaoum 2002;Debnath et al 2004;Xu et al 2012;Bandyopadhyay 2012;Rudra et al 2012;Rudra 2012) is given by the following relation,…”

Reexamining generalized Chaplygin gas with the sign-changeable interaction

“…Obviously, this system satisfies the fundamental theorem of differential equations in x − y plane. On the contrary, the autonomous system has a singular point in previous work (Xu et al 2012), so our autonomous system is an important advantage. Moreover, we obtain the following expression by Friedmann equation (5),…”

“…We find that there is only one physical critical point for the dynamical system with Q = 3βqH(ρ g + ρ m ) or Q = 3βqHρ g (see the Appendix) and there are two physical critical points in the system with Q = 3βqHρ m , as listed in Table 1. Therefore, only the interacting GCG cosmology with 3βqHρ m is physically acceptable and the other two including that in (Xu et al 2012) aren't acceptable on basis of the succession of cosmology epochs. In the next section, we will dynamically analyze the GCG cosmology with Q = 3βqHρ m in detail.…”

“…Recently, the interacting modified Chaplygin gas models are investigated by Xu et al (Xu et al 2012;Xu and Huang 2013). To analyze the dynamical system, the authors employed the dimensionless variables as follows…”

Viscous generalized Chaplygin gas interacting with f(R,T) gravity

“…Therefore, the energy-momentum tensor corresponding to the shear and bulk viscous fluid and generalized Chaplygin gas can be written as [41][42][43][44][45][46][47] …”