标题： 由具有一阶导数的混沌势产生的膨胀 显示英文标题

标题： Inflation from a chaotic potential with a step

摘要： 在这项工作中，我们研究了具有台阶的混沌势对膨胀宇宙相关观测参数的影响。我们在冷膨胀和温膨胀两种情况下数值演化扰动方程。 一方面，在冷膨胀场景中，我们以e-fold数$N_{e}$和比值$k/k_{0}$来分析标量功率谱$P_{\mathcal{R}}$，其中$k_{0}$是我们的基准尺度。我们展示了$P_{\mathcal{R}}$如何围绕$0.2< k/k_{0} < 20$振荡。 此外，我们展示了两个相关参数的演化：标量谱指数 $n_\mathrm{s}$ 和张量-标量比 $r$。 事实上，有不止一个 $(n_\mathrm{s},r)$ 的区域位于可观测窗口内（Planck 2018）。 另一方面，在温热暴胀的情况下，我们也考察了 $P_{\mathcal{R}}$ 随 $N_{e}$ 和 $k/k_{0}$ 的演化。 扰动在WI中被放大；实际上，$P_{\mathcal{R}}$可能比CMB值$P_{\mathcal{R}}> 2.22\times 10^{-9}$大得多。 此时，谱指数$n_\mathrm{s}$明显向蓝倾斜，在较小尺度上，张量与标量比值$r$变得太低。 然而，$n_\mathrm{s}$可以从蓝倾斜变为红倾斜，因为$P_{\mathcal{R}}$开始在$k/k_{0}\sim 40$附近振荡。 事实上，阶跃势垒的结果掠过了普朗克轮廓。 最后，这项研究的一个关键方面是比较两种范式下的膨胀势特征，实际上它们显示出相似性和差异性。 由于背景的特殊性和熵涨落的联合效应（仅在热膨胀中存在），在这两种情况下，某些波动尺度不再“冻结”在超视界尺度上。 显示英文摘要

摘要： In this work, we study the effects on the relevant observational parameters of an inflationary universe from a chaotic potential with a step. We numerically evolve the perturbation equations within both cold inflation and warm inflation. On the one hand, in a cold inflation scenario we analyse the scalar power spectrum $P_{\mathcal{R}}$ in terms of the number of e-folds $N_{e}$, and in terms of the ratio $k/k_{0}$, where $k_{0}$ is our pivot scale. We show how $P_{\mathcal{R}}$ oscillates around $0.2< k/k_{0} < 20$. Additionally, we present the evolution of two relevant parameters: the scalar spectral index $n_\mathrm{s}$ and the tensor-to-scalar ratio $r$. In fact, more than one region of $(n_\mathrm{s},r)$ lies within the observable window (Planck 2018). On the other hand, in the warm inflationary case, we also examine the evolution of $P_{\mathcal{R}}$ in terms of $N_{e}$ and $k/k_{0}$. Perturbations are amplified in WI; in fact, $P_{\mathcal{R}}$ can be much larger than the CMB value $P_{\mathcal{R}}> 2.22\times 10^{-9}$. This time, the spectral index $n_\mathrm{s}$ is clearly blue-tilted, at smaller scales, and the tensor-to-scalar ratio $r$ becomes too low. However, $n_\mathrm{s}$ can change from blue-tilted towards red-tilted, since $P_{\mathcal{R}}$ starts oscillating around $k/k_{0}\sim 40$. Indeed, the result from the step potential skims the Planck contours. Finally, one key aspect of this research was to contrast the features of an inflationary potential between both paradigms, and, in fact, they show similarities and differences. Due to a featured background and a combined effect of entropy fluctuations (only in warm inflation), in both scenarios certain fluctuation scales are not longer ``freeze in'' on super-horizon scales.