Gravitational wave spectrum induced by primordial scalar perturbations
Gravitational wave spectrum induced by primordial scalar perturbations
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DOI：
10.1103/physrevd.76.084019
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发表时间：
2007-10-01
影响因子：
5
通讯作者：
Ichiki, Kiyotomo
中科院分区：
文献类型：
--
作者：
Baumann, Daniel;Steinhardt, Paul;Ichiki, Kiyotomo
我们推导出了在所有可观测波长范围内由原始标量扰动引起的引力波的完整谱。标量引起的贡献可以直接从观测到的标量微扰和广义相对论中计算出来，在这个意义上，它与产生微扰的宇宙学模型无关。光谱在小尺度上是尺度不变的，但在大尺度和中等尺度上有一个有趣的尺度依赖性，标量引起的引力波不会红移，因此相对于宇宙的背景密度增强。这种对张量谱的贡献在形式上与直接依赖于模型的原始张量谱显著不同，尽管幅度很小，但它在某些宇宙学模型的原始信号中占主导地位。我们确认我们的分析结果，直接数值积分的运动方程。
We derive the complete spectrum of gravitational waves induced by primordial scalar perturbations ranging over all observable wavelengths. This scalar-induced contribution can be computed directly from the observed scalar perturbations and general relativity and is, in this sense, independent of the cosmological model for generating the perturbations. The spectrum is scale invariant on small scales, but has an interesting scale dependence on large and intermediate scales, where scalar-induced gravitational waves do not redshift and are hence enhanced relative to the background density of the Universe. This contribution to the tensor spectrum is significantly different in form from the direct model-dependent primordial tensor spectrum and, although small in magnitude, it dominates the primordial signal for some cosmological models. We confirm our analytical results by direct numerical integration of the equations of motion.