论文标题
宇宙学上绝热模式和$δ$ n形式主义的最新信息
An update on adiabatic modes in cosmology and $δ$N formalism
论文作者
论文摘要
在本文中，我们概括了温伯格的程序，以确定非吸引者通货膨胀制度的Comvature Curvature扰动$ \ cal r $。我们表明，$ \ cal r $的两种模式都与牛顿仪表中扰动方程的对称性有关。作为副产品，我们澄清的是，绝热通常并不意味着$ \ cal r $，甚至在$ k \ rightarrow 0 $限制中也不意味着恒定。然后，我们证明存在$Δn$的非等效定义，这些定义将重现$ \ Mathcal {r} $或统一密度曲率扰动$ζ$在线性顺序上。然后，我们表明，就不同仪表的电子折叠数量之间的差异而言，扰动$Δn$的定义可以在梯度扩展中以领先顺序非扰动地扩展。然而，根据本地FRW宇宙的演变获得的电子折叠差的计算机友好定义，分别具有扰动和不受干扰的初始条件，可能只提供有关线性顺序曲率扰动的信息，与文献中所述的相反。
In this paper, we generalize the Weinberg's procedure to determine the comoving curvature perturbation $\cal R$ to non-attractor inflationary regimes. We show that both modes of $\cal R$ are related to a symmetry of the perturbative equations in the Newtonian gauge. As a byproduct, we clarify that adiabaticity does not generally imply constancy of $\cal R$, not even in the $k\rightarrow 0$ limit. We then show that there exist non-equivalent definitions of $δN$ that would reproduce $\mathcal{R}$ or the uniform density curvature perturbation $ζ$ at linear order. We have then shown that the perturbative $δN$ definition in terms of difference between the number of e-foldings of different gauges, can be extended non-perturbatively at leading order in gradient expansion. Nevertheless, the computer friendly definition in terms of the difference of e-foldings obtained from the evolution of a local FRW Universe, respectively with perturbed and un-perturbed initial conditions, might only give information about the linear order curvature perturbations, contrary to what stated in the literature.
