论文标题
在扩展重力理论中弹跳模型
Bouncing Models in an Extended Gravity Theory
论文作者
论文摘要
在扩展的重力理论的框架内研究了一些弹跳模型。扩展重力模型是一般相对性的简单扩展,其中引入了其他物质几何耦合以说明较晚的宇宙速度升高现象。模型的动力学在FRW宇宙的背景下进行了讨论。一些可行的模型是针对特定假定的弹跳量表因子重建的。发现模型的行为主要由相应模型的参数决定。基于重力的最小物质几何耦合参数具有去除弹跳时期发生的欧米茄奇异性的作用。值得注意的是,构造的模型违反了能量条件,但是在某些情况下,这种违规导致模型在幻影阶段的演变。在线性均匀扰动下分析了模型的稳定性,发现在弹跳附近,模型显示出不稳定的能力,但扰动会平稳地衰减以在后期提供稳定的模型。
Some bouncing models are investigated in the framework of an extended theory of gravity. The extended gravity model is a simple extension of the General Relativity where an additional matter geometry coupling is introduced to account for the late time cosmic speed up phenomena. The dynamics of the models are discussed in the background of a flat FRW universe. Some viable models are reconstructed for specifically assumed bouncing scale factors. The behavior of the models are found to be decided mostly by the parameters of the respective models. The extended gravity based minimal matter-geometry coupling parameter has a role to remove the omega singularity occurring at the bouncing epoch. It is noted that the constructed models violate the energy conditions, however, in some cases this violation leads to the evolution of the models in phantom phase. The stability of the models are analyzed under linear homogeneous perturbations and it is found that, near the bounce, the models show instability but the perturbations decay out smoothly to provide stable models at late times.