标题： 通胀是如何发生的？ 显示英文标题

标题： How Accidental was Inflation?

摘要： 宇宙微波背景（CMB）的数据正在区分不同的暴胀模型，排除了简单的单项式势能模型，同时与那些预测类似于斯塔洛宾斯基（Starobinsky）$R + R^2$宇宙学模型的结果的模型一致。 然而，该模型可能面临理论上的问题，因为它需要一个较大的初始场值，这威胁到有效场论的有效性。 这一点可以通过沼泽地距离猜想来量化，该猜想预测了一组与有效紫外截断相关的轻态的出现。 对于延长暴胀期的情况，这可能会低于暴胀尺度，从而引发初始条件的额外问题。 无尺度超引力模型可以重现斯塔洛宾斯基模型的预测，并通过在$10^{-5}$水平上参数的精细调整来适应CMB数据。 在这里，我们基于弦理论中斯塔洛宾斯基模型的具体实现提出了解决这一问题的方法，其中这个“变形”参数是可计算的，并且取值接近于对应于斯塔洛宾斯基暴胀子势能的那个值。 在这个范围内，存在一些参数值能够更容易地适应普朗克、ACT和DESI BAO数据的组合，同时也限制了可能的暴胀场值范围，从而避免了沼泽地问题，并预测与CMB数据兼容的暴胀初始条件是普遍的。 显示英文摘要

摘要： Data on the cosmic microwave background (CMB) are discriminating between different models of inflation, disfavoring simple monomial potentials whilst being consistent with models whose predictions resemble those of the Starobinsky $R + R^2$ cosmological model. However, this model may suffer from theoretical problems, since it requires a large initial field value, threatening the validity of the effective field theory. This is quantified by the Swampland Distance Conjecture, which predicts the appearance of a tower of light states associated with an effective ultra-violet cutoff. This could be lower than the inflation scale for cases with an extended period of inflation, leading to an additional problem of initial conditions. No-scale supergravity models can reproduce the predictions of the Starobinsky model and accommodate the CMB data at the expense of fine-tuning of parameters at the level of $10^{-5}$. Here, we propose a solution to this problem based on an explicit realisation of the Starobinsky model in string theory, where this `deformation' parameter is calculable and takes a value of order of the one corresponding to the Starobinsky inflaton potential. Within this range, there are parameter values that accommodate more easily the combination of Planck, ACT and DESI BAO data, while also restricting the range of possible inflaton field values, thereby avoiding the swampland problem and predicting that the initial conditions for inflation compatible with the CMB data are generic.