论文标题
长宇宙弦的随机重力波
Stochastic gravitational waves from long cosmic strings
论文作者
论文摘要
我们计算由长宇宙字符串网络在整个宇宙历史中演变而成的随机引力波背景（SGWB）的预期应变功率谱和能量密度参数。与其他研究相反，丢弃了宇宙弦环的贡献，我们的结果提供了适用于大多数字符串模型的预期信号的强大下限。我们的方法使用Nambu-Goto数值模拟，在辐射，过渡和物质时代运行，其中我们计算了两点不等的各向异性应力相关器。这些是在张量模式的线性运动方程式中充当源术语，我们使用精确的绿色功能积分来求解。今天，我们发现重新固定的应变功率谱$（k/\ Mathcal {h} _0）^2 \ Mathcal {p} _h $在哈勃尺度和展览上的峰值，在大的波士仪上，在巨大的波型，高频振荡周围的高频振荡，幅度为100 $ 100（gu）^2 $。大多数高频功率是由物质时代中存在的长字符串产生的，辐射时代的贡献较小。
We compute the expected strain power spectrum and energy density parameter of the stochastic gravitational wave background (SGWB) created by a network of long cosmic strings evolving during the whole cosmic history. As opposed to other studies, the contribution of cosmic string loops is discarded and our result provides a robust lower bound of the expected signal that is applicable to most string models. Our approach uses Nambu-Goto numerical simulations, running during the radiation, transition and matter eras, in which we compute the two-point unequal-time anisotropic stress correlators. These ones act as source terms in the linearised equations of motion for the tensor modes, that we solve using an exact Green's function integrator. Today, we find that the rescaled strain power spectrum $(k/\mathcal{H}_0)^2 \mathcal{P}_h$ peaks on Hubble scales and exhibits, at large wavenumbers, high frequency oscillations around a plateau of amplitude $100 (GU)^2$. Most of the high frequency power is generated by the long strings present in the matter era, the radiation era contribution being smaller.
