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arXiv 2010.04027gr-qcastro-ph.CO
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煎饼与瑞士奶酪的区别

Pancakes as opposed to Swiss Cheese

Sebastián Nájera, Roberto A. Sussman

摘要:

我们研究了一类新的玩具模型的宇宙不均匀性,沿着一个合适的超曲面平滑匹配的任意数量的部分的“准平坦”的不均匀和各向异性Szekeres-II模型的任何空间平坦的宇宙学,可以描述的罗伯逊-瓦克度规(包括德西特,反德西特和闵可夫斯基时空)的部分。由此产生的“煎饼”模型是准平面类似物,在文献中发现的众所周知的球形“瑞士奶酪”模型。由于Szekeres-II模型可以,在一般情况下,兼容范围广泛的源(耗散流体,非共动流体的混合物,流体与标量或磁场或引力波的混合物),煎饼配置,我们提出允许嵌入在罗伯逊-瓦克几何形状的本地化源的广泛收集的描述。我们提供了各种简单的例子,任意数量的Szekeres-II区域(其来源是共动尘埃和能量通量解释为一个领域的奇特速度)与爱因斯坦德西特,$Λ$ CDM和德西特背景相匹配。我们还证明了Szekeres-II区域可以严格地被视为“精确”扰动的背景定义的匹配上面讨论的。我们相信,这些模型可以是有用的,以测试想法的平均和反作用和宇宙演化和观测的不均匀性的影响。

英文摘要:

We examine a novel class of toy models of cosmological inhomogeneities by smoothly matching along a suitable hypersurface an arbitrary number of sections of "quasi flat" inhomogeous and anisotropic Szekeres-II models to sections of any spatially flat cosmology that can be described by the Robertson-Waker metric (including de Sitter, anti de Sitter and Minkowski spacetimes). The resulting "pancake" models are quasi-flat analogues to the well known spherical "Swiss-cheese" models found in the literature. Since Szekeres-II models can be, in general, compatible with a wide range of sources (dissipative fluids, mixtures of non-comoving fluids, mixtures of fluids with scalar or magnetic fields or gravitational waves), the pancake configurations we present allow for a description of a wide collection of localized sources embedded in a Robertson-Waker geometry. We provide various simple examples of arbitrary numbers of Szekeres-II regions (whose sources are comoving dust and energy flux interpreted as a field of peculiar velocities) matched with Einstein de Sitter, $Λ$CDM and de Sitter backgrounds. We also prove that the Szekeres-II regions can be rigorously regarded as "exact" perturbations on a background defined by the matching discussed above. We believe that these models can be useful to test ideas on averaging and backreaction and on the effect of inhomogeneities on cosmic evolution and observations.

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。

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