Neutrinos, as the anisotropic stress tensor, have a damping effect on the tensor mode perturbation from inflation to the Λ dominated era. First, we study the squared amplitude reduction for the wavelength entering the horizon during radiation and matter-dominated phases in the negatively curved de Sitter spacetime. Then, by comparing with other spatial spacetimes, $K=0$ and $K=1$, the highest difference between closed and open cases is seen in the matter-dominated era. Thus, neutrinos can be added as another candidate for determining the nature of space-time.

中文翻译：

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中微子作为曲率探测器

中微子作为各向异性应力张量，对从暴胀到 Λ 主导时代的张量模式扰动具有阻尼作用。首先，我们研究了在负弯曲的德西特时空的辐射和物质主导阶段期间进入地平线的波长的平方振幅减小。然后，通过与其他空间时空的比较，$钾=0$ 和 $钾=1$，封闭式和开放式案件之间的最大差异出现在物质主导的时代。因此，可以添加中微子作为确定时空性质的另一个候选者。