新变量修正的Chaobergin气体如何有效地发挥暗能量的作用--RS II Brane模型中的动力学系统分析
How effective is new variable modified Chaplygin gas to play the role of dark energy- A dynamical system analysis in RS II Brane model
Prabir Rudra, Chayan Ranjit, Sujata Kundu
备注：
22 pages, 12 figures. arXiv admin note: substantial text overlap with arXiv:1206.1767, arXiv:1109.1481, arXiv:1204.3531; and text overlap with arXiv:1102.2758 by other authors
Motivated by some previous works of Rudra et al we set to explore the background dynamics when dark energy in the form of New Variable Modified Chaplygin gas is coupled to dark matter with a suitable interaction in the universe described by brane cosmology. The main idea is to find out the efficiency of New variable modified Chaplygin gas to play the role of DE. As a result we resort to the technique of comparison with standard dark energy models. Here the RSII brane model have been considered as the gravity theory. An interacting model is considered in order to search for a possible solution of the cosmic coincidence problem. A dynamical system analysis is performed because of the high complexity of the system . The statefinder parameters are also calculated to classify the dark energy model. Graphs and phase diagrams are drawn to study the variations of these parameters and get an insight into the effectiveness of the dark energy model. It is also seen that the background dynamics of New Variable Modified Chaplygin gas is consistent with the late cosmic acceleration. After performing an extensive mathematical analysis, we are able to constrain the parameters of new variable modified Chaplygin gas as $m<n$ to produce the best possible results. Future singularities are studied and it is found that the model has a tendency to result in such singularities unlike the case of generalized cosmic Chaplygin gas. Our investigation leads us to the fact that New Variable Modified Chaplygin gas is not as effective as other Chaplygin gas models to play the role of dark energy.
Study of Some Parameters of Modified Chaplygin Gas in Galileon Gravity Theory from Observational Perspective
我们假设了伽利略引力下的FRW宇宙模型，其中充满了暗物质和修正的Chaubergin气体（MCG）类型的暗能量。我们用红移$z$表示一些未知参数和观测参数的哈勃参数。重建了一些宇宙学参数，并生成了图来研究模型的性质及其可行性。可以看出，该模型与目前的宇宙加速完全一致。从12个点的\textit{observed Hubble data (OHD) set or Stern data set}出发，通过极小化$χ^{2}$检验，得到了任意参数（$A,B$）和（$A,C$）的界.其次，通过对\textit{Stern+BAO}和\textit{Stern+BAO+CMB}观测值的联合分析，我们还通过固定其他一些参数得到了参数（$A,B$）和（$A,C$）的最佳拟合值和界。在\textit{Stern, Stern+BAO and Stern+BAO+CMB}关节分析的置信水平为66%、90%和99%时，获得了参数的最佳拟合值和界限。接下来，我们也采取了Ia型超新星数据集（联盟2数据集，557个数据点）。对Galileon引力下的MCG理论模型的距离模$μ(z)$对红移$z$的最佳拟合值和观测到的\textit{SNe Ia union 2 data}样本进行了检验，得出了我们的模型与联合2样本数据一致的结论。
