论文标题
宇宙学原理中的倾斜不稳定
A Tilt Instability in the Cosmological Principle
论文作者
论文摘要
我们表明,即使宇宙正在加速,Friedmann-Lema-Robertson-Walker(FLRW)框架也无法朝着流体流动性的生长增长。物质部门中的这种流动(倾斜)不稳定性是宇宙无毛定理的参数,通常仅标记标准中的剪切各向异性。我们在``偶极宇宙学''的环境中说明了我们的主张,这是可以容纳流动的FLRW的最大哥白尼概括。简单的模型足以证明宇宙流也不必跟踪剪切,即使存在正宇宙的存在。我们还强调,如果状态的总方程$ W(t)\ rightarrow -1 $在后期(如标准宇宙学中所做的那样),那么倾斜头发的生长是相当通用的。我们的理论结果的一般性使有关迟到的各向异性和宇宙偶极子的各种观察性主张置于新的角度。
We show that the Friedmann-Lemaître-Robertson-Walker (FLRW) framework has an instability towards the growth of fluid flow anisotropies, even if the Universe is accelerating. This flow (tilt) instability in the matter sector is invisible to Cosmic No-Hair Theorem-like arguments, which typically only flag shear anisotropies in the metric. We illustrate our claims in the setting of ``dipole cosmology'', the maximally Copernican generalization of FLRW that can accommodate a flow. Simple models are sufficient to show that the cosmic flow need not track the shear, even in the presence of a positive cosmological constant. We also emphasize that the growth of the tilt hair is fairly generic if the total equation of state $w(t) \rightarrow -1$ at late times (as it does in standard cosmology), irrespective of the precise model of dark energy. The generality of our theoretical result puts various recent observational claims about late time anisotropies and cosmic dipoles in a new light.