论文标题
使用Chaplygin气体的椭圆形宇宙改进了CMB四极杆问题的解决方案
Improved solution to CMB quadrupole problem using ellipsoidal Universes with Chaplygin gas
论文作者
论文摘要
表现出包含均匀磁场，字符串或域壁的宇宙显示具有椭圆形膨胀。该病例具有观察性宇宙学的动机，尤其是与Planck数据中最佳拟合$λ$ CDM预测相比，有关低四极振幅的异常动机。结果表明，具有偏心率时具有偏心率的宇宙$ 10^{ - 2} $可以减少四极振幅，而不会影响温度各向异性的角度功率频谱的较高多物。我们首次使用动力学系统技术研究椭圆形宇宙的演变。确定的关键点在马鞍和过去的吸引子之间因暗能量状态方程参数$W_λ$而有所不同，而没有未来的吸引子。使用多个初始条件完成的该动力系统的数值集成显示了重要的结果。例如，观察到平面轴和垂直轴之间高膨胀差异的趋势与先前对椭圆形宇宙进化行为的假设相矛盾。将暗能量视为Chaplygin气体通过控制宇宙剪切演化来解决这一矛盾。
A Universe containing uniform magnetic fields, strings, or domain walls is shown to have an ellipsoidal expansion. This case has motivations from observational cosmology especially the anomaly concerning the low quadrupole amplitude compared to the best-fit $Λ$CDM prediction in Planck data. It is shown that a Universe with eccentricity at decoupling of order $10^{-2}$ can reduce the quadrupole amplitude without affecting higher multipoles of the angular power spectrum of the temperature anisotropy. We study the evolution of ellipsoidal Universes using dynamical system techniques for the first time. The determined critical points vary between saddle and past attractors depending on dark energy state equation parameter $w_Λ$, with no future attractors. Important results are shown with numerical integrations of this dynamical system done using several initial conditions. For instance, a tendency for high expansion differences between planar and perpendicular axes is observed which contradicts previous assumption on the evolution behaviour of ellipsoid Universes. Considering dark energy as a Chaplygin gas solves this contradiction by controlling cosmic shear evolution.
