论文标题
大型多项式通胀：参数空间，预测和（双重）永恒性质
Large Field Polynomial Inflation: Parameter Space, Predictions and (Double) Eternal Nature
论文作者
论文摘要
最近的观察结果排除了简单的单一通货膨胀情况。在这项工作中，我们重新审视了下一个最简单的场景，即单场模型，其中标量电势是第四度的多项式，其具有凹面的``几乎''鞍点。我们专注于变形 - planckian字段值。我们对电势进行修复，这大大简化了查找接受键模型参数的过程。这允许对最近的Planck和Bicep/Keck 2018测量结果进行首次全面扫描参数空间。即使对于trans-planckian字段值，张量比$ r $ tensor tensor-scalar比率$ r $也可以小于$ \ nathcal {o}（10^{ - 8}）$，但该模型也可以使当前上限饱和。与该模型的小型版本相反，辐射稳定性不会导致对通电电位参数的强大限制。对于非常大的场值，可以通过四分之一项近似电势；众所周知，这允许将永恒的通货膨胀对于远低于降低的普朗克质量$ m _ {\ rm pl} $，而哈勃参数$ h \ sim 10^{ - 2} m _ {\ rm pl} $。更有趣的是，我们找到一个参数空间区域，甚至支持{\ em的两个阶段的永恒通胀}。第二个时代仅在will的斜率很小时才发生，并且具有$ h \ sim 10^{ - 5} m _ {\ rm pl} $;只有在$ r \ sim 10^{ - 2} $（在Next-Next-Generation CMB观测值的灵敏度范围内）之内，才能实现它。
Simple monomial inflationary scenarios have been ruled out by recent observations. In this work we revisit the next simplest scenario, a single--field model where the scalar potential is a polynomial of degree four which features a concave ``almost'' saddle point. We focus on trans--Planckian field values. We reparametrize the potential, which greatly simplifies the procedure for finding acceptbale model parameters. This allows for the first comprehensive scan of parameter space consistent with recent Planck and BICEP/Keck 2018 measurements. Even for trans--Planckian field values the tensor--to--scalar ratio $r$ can be as small as $\mathcal{O}(10^{-8})$, but the model can also saturate the current upper bound. In contrast to the small--field version of this model, radiative stability does not lead to strong constraints on the parameters of the inflaton potential. For very large field values the potential can be approximated by the quartic term; as well known, this allows eternal inflation even for field energy well below the reduced Planck mass $M_{\rm Pl}$, with Hubble parameter $H \sim 10^{-2} M_{\rm Pl}$. More interestingly, we find a region of parameter space that even supports {\em two phases of eternal inflation}. The second epoch only occurs if the slope at the would--be saddle point is very small, and has $H \sim 10^{-5} M_{\rm Pl}$; it can only be realized if $r \sim 10^{-2}$, within the sensitivity range of next--generation CMB observations.
