发表机构
Indian Institute of Technology, Kanpur; Indian Institute of Science Education and Research, Bhopal（坎普尔印度理工学院; 博帕尔印度科学教育研究所）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
该研究从恒定滚动条件推导标量功率谱和谱指数，利用普朗克2018和ACT DR6数据约束参数，证明恒定滚动暴胀在观测上与慢滚动暴胀竞争力相当甚至略优。
AI 中文摘要
从恒定滚动条件出发，该条件涉及恒定滚动参数$\beta$，它是恒定滚动暴胀模型中的一个基本常数，我们推导了标量功率谱，并得到了标量谱指数$n_s$关于$\beta$和剩余e折数$\tilde N$的解析表达式。所得关系在$\beta$中是非单调的，允许两个不同的恒定滚动分支，一个具有$\beta<0$，另一个具有$\beta>0$，来重现几乎相同的观测标量倾斜。我们使用普朗克2018年CMB数据，以及进一步使用普朗克2018年+ACT DR6的联合数据来约束$\beta$。对于普朗克2018年，$\beta$的后验分布呈现出与两个解析分支相关的双峰结构，而普朗克+ACT联合分析收紧了$\beta$的允许范围，并显示出与$\beta=0$慢滚动类谱点的持续一致性。数据将$\beta$约束为较小值，但并未要求其精确为零。我们还通过使用枢轴尺度上的观测标量振幅归一化来估计暴胀质量尺度$M$。负和正$\beta$分支都给出了$M\sim10^{-5}M_{\rm Pl}$量级的高尺度暴胀归一化。我们表明，$\beta \to 0$极限仅在谱上是慢滚动类的，但并不重现标准慢滚动动力学。我们的结果表明，恒定滚动暴胀在观测上与通常的慢滚动暴胀范式具有竞争力。与慢滚动暴胀模型相比，恒定滚动暴胀模型同样好或略微更好地得到了最新CMB观测的支持。
英文摘要
Starting from the constant-roll condition, which involves the constant-roll parameter $β$, which is a fundamental constant in the constant-roll inflationary models, we derive the scalar power spectrum and obtain an analytic expression for the scalar spectral index $n_s$ in terms of $β$ and the number of remaining e-folds $\tilde N$. The resulting relation is non-monotonic in $β$, allowing two distinct constant-roll branches, one with $β<0$ and one with $β>0$, to reproduce nearly the same observed scalar tilt. We constrain $β$ using Planck 2018 CMB data, and further using the combined Planck 2018 + ACT DR6 data. For Planck 2018, the posterior distribution of $β$ exhibits a bimodal structure associated with the two analytical branches, while the combined Planck+ACT analysis tightens the allowed range of $β$ and shows continued consistency with the $β=0$ slow-roll-like spectral point. The data constrain $β$ to be small, but do not require it to vanish exactly. We also estimate the inflationary mass scale $M$ by using the observed scalar-amplitude normalization at the pivot scale. Both the negative and positive $β$ branches give a high-scale inflationary normalization of order $M\sim10^{-5}M_{\rm Pl}$. We show that the $β\to 0$ limit is only spectrally slow-roll like, but does not reproduce standard slow-roll dynamics. Our results show that constant-roll inflation is observationally competitive with the usual slow-roll inflationary paradigm. The constant roll inflation model is supported by the latest CMB observations equally well or marginally better when compared with the slow roll inflation model.
