标题： 在布兰斯-迪克 chaotic inflation 中，广义相对论有多典型？ 显示英文标题

标题： How typical is General Relativity in Brans-Dicke chaotic inflation?

摘要： 广义相对论在大$\omega$极限下可以从布兰斯-迪克引力中恢复。在本文中，我们研究了具有混沌暴胀的布兰斯-迪克引力理论，允许$\omega$为常数值或变数值，分别称为扩展暴胀和超扩展暴胀。本文的主要重点放在后者上。相对于布兰斯-迪克场的变分$\omega$基于类似于弦理论中稀释子场的高阶修正，遵循布兰斯-迪克场和度规场渐近解耦的简单原理。所讨论的问题是，宇宙大部分区域是否主导着大$\omega$值，这将导致结论：典型区域实际上由广义相对论支配。在这些理论中，我们发现可以构造驱动布兰斯-迪克场在暴胀结束时演化到适当值范围的暴胀势，使得大$\omega$在宇宙的平均区域确实是典型的。然而，一般来说，这一结论并不成立，并且表明对于一大类暴胀势，广义相对论并不是先验的典型理论。 显示英文摘要

摘要： General Relativity is recovered from Brans-Dicke gravity in the limit of large $\omega$. In this article we investigate theories of Brans-Dicke gravity with chaotic inflation, allowing for either a constant or variable value of $\omega$, known as extended and hyperextended inflation respectively. The main focus of the paper is placed on the latter. The variation $\omega$ with respect to the Brans-Dicke field is based on higher-order corrections analogous to those of the dilaton field in string theory, following the simple principle that the Brans-Dicke and metric fields decouple asymptotically. The question addressed is whether a large value of $\omega$ is predominant in most regions of the universe, which would lead to the conclusion that a typical region is then governed by General Relativity. In these theories we find that it is possible to construct inflaton potentials that drive the evolution of the Brans-Dicke field to an appropriate range of values at the end of inflation, such that a large $\omega$ is indeed typical in an average region of the universe. However, in general this conclusion does not hold and it is shown that for a wide class of inflaton potentials General Relativity is not a priori a typical theory.