标题： 正则化极点暴胀和爱因斯坦-嘉当引力中的 $n_s$ 增加 显示英文标题

标题： Increase of $n_s$ in regularized pole inflation & Einstein-Cartan gravity

摘要： 我们展示了在极点暴胀中正则化二阶极点可以诱导$n_s$的增加，这在阿塔卡马宇宙学望远镜（ACT）最新发布的宇宙微波背景（CMB）观测数据之后可能变得重要。 极点暴胀被知为能够统一描述吸引子模型，即它们可以在给定一般势的情况下生成一个平坦的平台期。 最近的ACT观测表明，CMB尺度上标量谱指数$n_s$的约束可能会比Starobinsky模型、希格斯暴胀和$\alpha$-吸引子模型的预测值更大，这促使我们考虑修改极点暴胀。 我们发现，如果我们正则化动能项中的二阶极点，使得动能项在整个场范围内变得规则，那么我们可以普遍增加$n_s$，因为在大场区域势能会被提升。 我们已经明确地证明了这种类型的正则化极点暴胀可以从爱因斯坦-卡坦形式主义自然产生，并且暴胀预测与最新的ACT数据一致，而不会破坏$\alpha$-吸引子模型的成功。 显示英文摘要

摘要： We show that the regularization of the second order pole in the pole inflation can induce the increase of $n_s$, which may be important after the latest data release of cosmic microwave background (CMB) observation by Atacama Cosmology Telescope (ACT). Pole inflation is known to provide a unified description of attractor models that they can generate a flat plateau for inflation given a general potential. Recent ACT observation suggests that the constraint on the scalar spectral index $n_s$ at CMB scale may be shifted to a larger value than the predictions in the Starobinsky model, the Higgs inflation, and the $\alpha$-attractor model, which motivates us to consider the modification of the pole inflation. We find that if we regularize the second order pole in the kinetic term such that the kinetic term becomes regular for all field range, we can generally increase $n_s$ because the potential in the large field regime will be lifted. We have explicitly demonstrated that this type of regularized pole inflation can naturally arise from the Einstein-Cartan formalism, and the inflationary predictions are consistent with the latest ACT data without spoiling the success of the $\alpha$-attractor models.