arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新，休息一下吧，周末愉快~~
arXiv 1607.07347hep-thastro-ph.COgr-qc
收藏

不同维空间平坦Einstein-Gauss-Bonnet模型的宇宙动力学：低维$Λ$项情形

Cosmological dynamics of spatially flat Einstein-Gauss-Bonnet models in various dimensions: Low-dimensional $Λ$-term case

Sergey A. Pavluchenko

备注：
38 pages, 11 figures, 5 tables
发表信息：
Phys. Rev. D 94, 084019 (2016)
阅读 PDF
arXiv 页面 ↗HTML 原文 ↗

摘要：

本文系统地研究了具有$Λ$项的[（3+D）+1]维Einstein-Gauss-Bonnet宇宙学模型。我们考虑模型，拓扑是两个单位的迷向子空间具有不同的比例因子的产品。其中一个子空间是三维的，代表我们的空间，另一个是D维的，代表额外的维度。我们没有考虑尺度因子上的{ \it Answer}，这使得我们的结果相当一般。由于爱因斯坦-希尔伯特和高斯-邦纳的贡献都起作用，$D=1$和$D=2$的情况由于运动方程的不同结构而具有不同的动力学。我们分析研究在这两种情况下的运动方程，并描述所有可能的制度。结果表明，$D=1$情况下没有物理可行的制度，而$D=2$有从高能Kasner各向异性指数区的平滑过渡。这种转变发生在$α$和$Λ$的两个范围：$α> 0$、$Λ> 0$和$αΛ\leqslant 1/2$以及$α< 0$、$Λ> 0$和$αΛ< -3/2$。对于后一种情况，如果$αΛ= -3/2$，额外维度部分具有$h\to 0$，因此额外维度的大小（在比例因子的意义上）达到恒定值。我们报告了$D=1$和$D=2$病例之间以及这些病例与其真空对应病例之间的实质性差异，描述了所研究病例的特征，并讨论了差异的起源。

英文摘要：

In this paper we perform a systematic study of spatially flat [(3+D)+1]-dimensional Einstein-Gauss-Bonnet cosmological models with $Λ$-term. We consider models that topologically are the product of two flat isotropic subspaces with different scale factors. One of these subspaces is three-dimensional and represents our space and the other is D-dimensional and represents extra dimensions. We consider no {\it Ansatz} on the scale factors, which makes our results quite general. With both Einstein-Hilbert and Gauss-Bonnet contributions in play, the cases with $D=1$ and $D=2$ have different dynamics due to the different structure of the equations of motion. We analytically study equations of motion in both cases and describe all possible regimes. It is demonstrated that $D=1$ case does not have physically viable regimes while $D=2$ has smooth transition from high-energy Kasner to anisotropic exponential regime. This transition occurs for two ranges of $α$ and $Λ$: $α> 0$, $Λ> 0$ with $αΛ\leqslant 1/2$ and $α< 0$, $Λ> 0$ with $αΛ< -3/2$. For the latter case if $αΛ= -3/2$, extra dimensional part has $h\to 0$ and so the size of extra dimensions (in the sense of the scale factor) is reaching constant value. We report substantial differences between $D=1$ and $D=2$ cases and between these cases and their vacuum counterparts, describe features of the cases under study and discuss the origin of the differences.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

↑