Non-Gaussianities of primordial perturbations in the soft limit provide the important information about the light degrees of freedom during inflation. The soft modes of the curvature perturbations, unobservable for a local observer, act as rescaling the spatial coordinates. We determine how the trispectrum in the collapsed limit is shifted by the rescaling due to the soft modes. We find the form of the inequality between $f_{\rm NL}$ and $\tau_{\rm NL}$ parameters is not affected by the rescaling, demonstrating that the role of the inequality as an indicator of the light degrees of freedom remains intact. We also comment on the local observer effect on the consistency relation for ultra slow-roll inflation.

中文翻译：

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局部观察者对宇宙学软定理的影响

软极限中原始扰动的非高斯性提供了关于膨胀期间轻自由度的重要信息。局部观察者无法观察到的曲率扰动的软模式充当重新缩放空间坐标。我们确定了折叠极限中的三谱如何因软模式而被重新缩放。我们发现 $f_{\rm NL}$ 和 $\tau_{\rm NL}$ 参数之间的不等式形式不受重新缩放的影响，表明不等式作为轻自由度指标的作用完好无损。我们还评论了本地观察者对超慢速通胀一致性关系的影响。