Dirac-Born-Infeld和k-暴胀：来自弦论的CMB各向异性
Dirac-Born-Infeld and k-inflation: the CMB anisotropies from string theory
摘要：
弦论中的暴胀模型表现出不寻常的标量场动力学，涉及非最小动力学项，一般称为k-暴胀。在这种情况下，用来确定原始宇宙学扰动行为的标准慢滚方法就不能再使用了。我们提出了一种通用的方法，基于一致近似，解析地推导出原始功率谱的标量和张量扰动。在首阶，标量谱指数，它的运行和张量标量比修改的新动力学。给出了它们的新表达式，修正了以前的结果，澄清了当声视界和哈勃半径不同时张量标量比的定义.最后，我们讨论了编码的非最小动力学项的参数必须满足的约束条件，如声速和k-暴胀的能量尺度，鉴于第五年的威尔金森微波各向异性探测器（WMAP 5）的数据。
英文摘要：
Inflationary models within string theory exhibit unusual scalar field dynamics involving non-minimal kinetic terms and generically referred to as k-inflation. In this situation, the standard slow-roll approach used to determine the behavior of the primordial cosmological perturbations cannot longer be used. We present a generic method, based on the uniform approximation, to analytically derive the primordial power spectra of scalar and tensor perturbations. At leading order, the scalar spectral index, its running and the tensor-to-scalar ratio are modified by the new dynamics. We provide their new expression, correct previous results at next-to-leading order and clarify the definition of what is the tensor-to-scalar ratio when the sound horizon and Hubble radius are not the same. Finally, we discuss the constraints the parameters encoding the non-minimal kinetic terms have to satisfy, such as the sound speed and the energy scale of k-inflation, in view of the fifth year Wilkinson Microwave Anisotropy Probe (WMAP5) data.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
