The First Three Seconds: a Review of Possible Expansion Histories of the Early Universe
The First Three Seconds: a Review of Possible Expansion Histories of the Early Universe
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DOI：
10.21105/astro.2006.16182
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发表时间：
2020-06
影响因子：
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通讯作者：
R. Allahverdi;M. Amin;A. Berlin;N. Bernal;C. Byrnes;M. Sten Delos;A. Erickcek;M. Escudero;
中科院分区：
文献类型：
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作者：
R. Allahverdi;M. Amin;A. Berlin;N. Bernal;C. Byrnes;M. Sten Delos;A. Erickcek;M. Escudero;
人们普遍认为，宇宙的能量密度主要由膨胀后重新加热到 54,000 年后物质统治开始之间的辐射主导。虽然轻元素的丰度表明宇宙在大爆炸核合成（BBN）期间以辐射为主，但很少有证据表明宇宙在 BBN 之前以辐射为主。因此，宇宙学历史可能更加复杂，在最早的时代与标准辐射主导存在偏差。事实上，最近提出了一些关于各种主题的有趣建议，例如暗物质的产生、物质-反物质不对称性、引力波、原初黑洞或非标准膨胀阶段的微晕。在本文中，我们回顾了早期宇宙中辐射主导偏离的各种可能的原因和后果（发生在 BBN 之前或之后）以及对它们的限制，正如近年来文献中讨论的那样。
It is commonly assumed that the energy density of the Universe was dominated by radiation between reheating after inflation and the onset of matter domination 54,000 years later. While the abundance of light elements indicates that the Universe was radiation dominated during Big Bang Nucleosynthesis (BBN), there is scant evidence that the Universe was radiation dominated prior to BBN. It is therefore possible that the cosmological history was more complicated, with deviations from the standard radiation domination during the earliest epochs. Indeed, several interesting proposals regarding various topics such as the generation of dark matter, matter-antimatter asymmetry, gravitational waves, primordial black holes, or microhalos during a nonstandard expansion phase have been recently made. In this paper, we review various possible causes and consequences of deviations from radiation domination in the early Universe - taking place either before or after BBN - and the constraints on them, as they have been discussed in the literature during the recent years.