Blue-tilted tensor spectrum and thermal history of the Universe
Blue-tilted tensor spectrum and thermal history of the Universe
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DOI：
10.1088/1475-7516/2015/02/003
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发表时间：
2014-07
影响因子：
6.4
通讯作者：
S. Kuroyanagi;Tomo Takahashi;Shuichiro Yokoyama
中科院分区：
文献类型：
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作者：
S. Kuroyanagi;Tomo Takahashi;Shuichiro Yokoyama
我们研究了原始引力波(GWS)谱指数的限制条件，特别是蓝倾斜的谱。这样的约束可以用来测试早期宇宙的某一类模型。我们研究了LIGO+室女座的观测界限、脉冲星计时和大爆炸核合成，同时考虑了由于膨胀后再加热而导致的高频振幅的抑制以及后期的熵产生。通过改变再加热温度和后期产生的熵量等参数的值，给出了对光谱指数的约束。我们还考虑了通用建模方法下的约束条件，该方法可以近似描述早期宇宙的各种场景。我们证明了对蓝色光谱倾斜的限制强烈地依赖于基本的假设，并且在某些情况下，仍然可以允许高度蓝色倾斜的光谱。
We investigate constraints on the spectral index of primordial gravitational waves (GWs), paying particular attention to a blue-tilted spectrum. Such constraints can be used to test a certain class of models of the early Universe. We investigate observational bounds from LIGO+Virgo, pulsar timing and big bang nucleosynthesis, taking into account the suppression of the amplitude at high frequencies due to reheating after inflation and also late-time entropy production. Constraints on the spectral index are presented by changing values of parameters such as reheating temperatures and the amount of entropy produced at late time. We also consider constraints under the general modeling approach which can approximately describe various scenarios of the early Universe. We show that the constraints on the blue spectral tilt strongly depend on the underlying assumption and, in some cases, a highly blue-tilted spectrum can still be allowed.