Non-Gaussianity generated in inflation can be contributed by two parts. The first part, denoted by $f_{NL}^{δN}$, is the contribution from four-point correlation of inflaton field which can be calculated using $δN$ formalism, and the second part, denoted by $f_{NL}^{int}$, is the contribution from the three-point correlation function of the inflaton field. We consider the two contributions to the non-Gaussianity in noncanonical warm inflation throughout (noncanonical warm inflation is a new inflationary model which is proposed in \cite{Zhang2014}). We find the two contributions are complementary to each other. The four-point correlation contribution to the non-Gaussianity is overwhelmed by the three-point one in strong noncanonical limit, while the conclusion is opposite in the canonical case. We also discuss the influence of the field redefinition, thermal dissipative effect and noncanonical effect to the non-Gaussianity in noncanonical warm inflation.
Primordial non-Gaussianity in noncanonical warm inflation
研究了一类由非正则暖暴胀产生的均匀密度超曲面上的原始曲率扰动的双谱，其中暴胀由非正则标量暴胀子场提供，暴胀子场通过热耗散效应与辐射耦合.本文给出了描述一阶宇宙学扰动理论中非高斯性的非线性参量$f_{NL}$的解析形式，并分析了该非线性参量的大小。并将所得结果与标准暴胀和正则暖暴胀的结果进行了比较。我们还讨论了当二阶微扰理论对非高斯性的贡献变得更重要时，可以观察到什么样的影响。以Dirac Born Infeld（DBI）暴胀为例，研究了声速和热耗散强度对非高斯性的影响，得到了普朗克约束下声速的一个下界.
Dynamics of potential-free warm $\mathbf{k}$-inflation with nonminimal derivative coupling
School of Science, Qingdao University of Technology（青岛理工大学理学院）；School of Physics and Advanced Energy, Henan University of Technology（河南工业大学物理与能源工程学院）；College of Physics and Electronic Information, Inner Mongolia Normal University（内蒙古师范大学物理与电子信息学院）
本文提出了一个在弯曲喉道中相对论D-膜暴胀的温暴胀模型，它具有Dirac Born Infeld（DBI）动力学项，并通过耗散项与辐射耦合。扰动冻结在声地平线和功率谱的耗散参数和声速参数的组合确定。热耗散改善了{ \it eta}问题，软化了来自额外维度体积和来自张量标量比的观测界限的理论约束。暖DBI模型可以导致明显的等边型非高斯性。作为一个唯象模型，忽略紧化约束，我们表明，大场的温暖的通货膨胀模型不一定会产生一个大的张量标量比。
