发表机构
Université Paris-Saclay, CNRS, Institut d’Astrophysique Spatiale（巴黎萨克雷大学、法国国家科学研究中心、天体物理研究所）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文扩展分离宇宙方法至非最小耦合多场暴胀模型，验证其在大尺度微扰动力学的适用性，并推导波长下界，与爱因斯坦框架比较，在希格斯型玩具模型中验证。
AI 中文摘要
在本文中，我们将宇宙学微扰的分离宇宙方法有效性条件的研究，扩展到具有多个非最小耦合于引力的场的暴胀模型。分离宇宙方法将宇宙有效地描述为一系列均匀且各向同性的区域，从而在大尺度上对宇宙学微扰进行有效描述。这一近似是随机暴胀和$\delta N$形式主义中的必要步骤。我们研究并比较了在大尺度上宇宙学微扰理论的动力学，与在分离宇宙图像中导出的动力学，针对非线性sigma模型，其中我们允许场与引力之间存在非最小耦合。我们发现，分离宇宙方法能够充分再现大尺度微扰的动力学，前提是所考虑的模式的波长大于从我们所考虑模型的背景演化中导出的一个下界列表。然后，将这些下界与手头Jordan框架模型的经典等价爱因斯坦框架描述中导出的下界进行比较。特别是，这些条件是在大场极限下，针对一个类似希格斯粒子的暴胀玩具模型进行推导和比较的。
英文摘要
In this paper we extend a study of the validity conditions of the separate universe approach of cosmological perturbations to models of inflation with multiple fields that are non minimally coupled to gravity. The separate universe approach effectively describes the universe as a collection of homogeneous and isotropic patches, leading to an effective description of cosmological perturbations at large scales. This approximation is a necessary step in stochastic inflation and in the $δ\N$ formalism. We study and compare the dynamics of cosmological perturbation theory at large scales to the dynamics derived in the separate universe picture for non linear sigma models where we have allowed a non minimal coupling between the fields and gravity. We found that the separate universe approach adequately reproduces the dynamics of the large scale perturbations, provided the wavelength of the modes considered is greater than a list of lower bounds derived from the background evolution of the model we consider. These lower bounds are then compared to those derived in the classically equivalent Einstein frame description of the Jordan frame model at hand. In particular these conditions are derived and compared for a Higgs-like toy model of inflation in the large field limit.
Comments20 pages
