标题： 利用再加热预测和遗留引力波消除通货膨胀退化问题 显示英文标题

标题： Curing inflationary degeneracies using reheating predictions and relic gravitational waves

摘要： 众所周知，暴胀场景对于宇宙微波背景（CMB）可观测量的预测常常表现出不同的退化组。这些退化通常要么是因为多种暴胀模型对标量谱指数 $n_{_S}$ 和张量-标量比 $r$ 预测出相似的值，要么是因为在同一模型中，$\lbrace n_{_S}, r \rbrace$ 的值对某些模型参数不敏感，使得仅凭CMB观测难以构成对暴胀宇宙学的独特探测。 我们证明了，通过考虑后膨胀再加热参数的约束条件，例如再加热持续时间$N_{_{\rm re}}$、其温度$T_{_{\rm re}}$，尤其是其状态方程（EOS）$w_{_{\rm re}}$，可以在某些类别的暴胀模型中打破这种退化，其中相同的$\lbrace n_{_S}, r \rbrace$值可能对应于不同的再加热$w_{_{\rm re}}$。 特别是，我们展示了如何利用再加热约束来打破 T 模型和 E 模型$\alpha$吸引子中的暴胀退化。 非规范暴胀也进行了研究。 宇宙遗物引力波（GW）谱为我们提供了另一种打破暴胀退化的工具。 这是因为引力波谱对宇宙的后暴胀状态方程敏感。 确实，在再加热期间一个刚性的物态方程$(w_{_{\rm re}} > 1/3)$会在谱指数$n_{_{\rm GW}} = \frac{d\log{\Omega_{_{\rm GW}}}}{d\log{k}} > 0$中引起小尺度的蓝倾斜，而一个柔软的物态方程$(w_{_{\rm re}} < 1/3)$则会导致红倾斜。 因此，遗留下来的引力波$\lbrace n_{_S}, r\rbrace$可以为我们提供后膨胀时期有价值的信息，并且它们的频谱可以用来解决膨胀中的退化问题。 显示英文摘要

摘要： It is well known that the inflationary scenario often displays different sets of degeneracies in its predictions for CMB observables. These degeneracies usually arise either because multiple inflationary models predict similar values for the scalar spectral index $n_{_S}$ and the tensor-to-scalar ratio $r$, or because within the same model, the values of $\lbrace n_{_S}, r \rbrace$ are insensitive to some of the model parameters, making it difficult for CMB observations alone to constitute a unique probe of inflationary cosmology. We demonstrate that by taking into account constraints on the post-inflationary reheating parameters such as the duration of reheating $N_{_{\rm re}}$, its temperature $T_{_{\rm re}}$ and especially its equation of state (EOS), $w_{_{\rm re}}$, it is possible to break this degeneracy in certain classes of inflationary models where identical values of $\lbrace n_{_S}, r \rbrace$ can correspond to different reheating $w_{_{\rm re}}$. In particular, we show how reheating constraints can break inflationary degeneracies in the T-model and the E-model $\alpha$-attractors. Non-canonical inflation is also studied. The relic gravitational wave (GW) spectrum provides us with another tool to break inflationary degeneracies. This is because the GW spectrum is sensitive to the post-inflationary EOS of the universe. Indeed a stiff EOS during reheating $(w_{_{\rm re}} > 1/3)$ gives rise to a small scale blue tilt in the spectral index $n_{_{\rm GW}} = \frac{d\log{\Omega_{_{\rm GW}}}}{d\log{k}} > 0$, while a soft EOS $(w_{_{\rm re}} < 1/3)$ results in a red tilt. Relic GWs therefore provide us with valuable information about the post-inflationary epoch, and their spectrum can be used to cure inflationary degeneracies in $\lbrace n_{_S}, r\rbrace$.