Gravitational wave and CMB probes of axion kination
Gravitational wave and CMB probes of axion kination
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DOI：
10.1007/jhep09(2022)116
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发表时间：
2021-08
影响因子：
5.4
通讯作者：
R. Co;D. Dunsky;N. Fernandez;A. Ghalsasi;L. Hall;K. Harigaya;J. Shelton
中科院分区：
文献类型：
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作者：
R. Co;D. Dunsky;N. Fernandez;A. Ghalsasi;L. Hall;K. Harigaya;J. Shelton
轴子场在场空间中的旋转为动能支配时代提供了一个自然的起源，在这个时代，能量密度由轴子场的动能项支配，而在此之前是物质支配的早期时代。值得注意的是，在物质支配的结束时没有熵产生，因此这些物质和动能支配的时代甚至可能发生在大爆炸核合成之后。我们从宇宙微波背景辐射和大爆炸核合成两个方面推导出对这些时代的限制。我们研究了这种宇宙学场景如何影响可能的原始引力波的频谱，并发现频谱具有三角形峰。我们讨论了未来的引力波观测如何探测可行的参数空间，包括由动力学失调机制产生轴子暗物质或由轴生作用产生重子不对称的区域。对于由动力学错位机制产生的QCD轴子暗物质，暴胀引力波谱的修改发生在0.01 Hz以上，并且对于高值的暴胀能量标度，发现的前景是好的。我们简要地评论宇宙的结构形成的影响。
Rotations of an axion field in field space provide a natural origin for an era of kination domination, where the energy density is dominated by the kinetic term of the axion field, preceded by an early era of matter domination. Remarkably, no entropy is produced at the end of matter domination and hence these eras of matter and kination domination may occur even after Big Bang Nucleosynthesis. We derive constraints on these eras from both the cosmic microwave background and Big Bang Nucleosynthesis. We investigate how this cosmological scenario affects the spectrum of possible primordial gravitational waves and find that the spectrum features a triangular peak. We discuss how future observations of gravitational waves can probe the viable parameter space, including regions that produce axion dark matter by the kinetic misalignment mechanism or the baryon asymmetry by axiogenesis. For QCD axion dark matter produced by the kinetic misalignment mechanism, a modification to the inflationary gravitational wave spectrum occurs above 0.01 Hz and, for high values of the energy scale of inflation, the prospects for discovery are good. We briefly comment on implications for structure formation of the universe.