宇宙中张量模式的阻尼
摘要
我们给出自由流动中央轻子引起的各向异性应力张量无标量部分的解析公式，并据此推导宇宙引力波传播的积分-微分方程。解表明，各向异性应力使平方振幅降低 35.6%，此值对应于波长在辐射主导阶段进入视界的波长，与任何宇宙参数无关。这会使这些波长的张量温度与偏振相关函数降低相同比例。该效应随波长进入视界时间较晚而减弱。在最长波长处，由于夸克自由流动导致的张量相关函数降低范围为 10.7%（当 Ω_M h^2 = 0.1 时）至 9.0%（当 Ω_M h^2 = 0.15 时）。附录给出了张量模式及标量模式在视界外满足守恒律的一般证明，即便各向异性应力张量不可忽略。
引用
@article{arxiv.astro-ph/0306304,
title = {Damping of Tensor Modes in Cosmology},
author = {Steven Weinberg},
journal= {arXiv preprint arXiv:astro-ph/0306304},
year = {2009}
}
备注
14 pages. The original version of this paper has been expanded to deal with perturbations of any wavelength. While for wavelengths short enough to enter the horizon during radiation dominance, temperature and polarization correlations are damped by 35.6%, at the longest wavelengths the damping is from 9.0% to 11%. An added Appendix gives a general proof that tensor as well as scalar modes satisfy a conservation law outside the horizon, even during neutrino decoupling. Some references are also added