AI 中文总结
研究多场暴胀中原初非高斯性，通过构建修饰传播子等方法，在强混合下推导树级双谱积分表示，得到双谱贡献表达式及标度律，为强混合暴胀相关研究打开新窗口并建立框架。
AI 中文摘要
我们对多场暴胀中的原初非高斯性进行了一种解析处理，该处理在常曲率 - 等曲率混合强度λ中是非微扰的。利用耦合曲率微扰ζ和等曲率微扰σ的精确线性解，我们构建了修饰传播子，并推导了由相互作用\(\dot\zeta^2\sigma\)、\(\dot\zeta\,\sigma^2\)和\(\sigma^3\)产生的树级双谱的精确积分表示。这种形式体系将曲率 - 等曲率转移重整到λ的所有阶次，并适用于熵质量μ的任意值。我们得到了双谱贡献的主导挤压极限的封闭形式表达式，并在弱混合极限下恢复了著名的宇宙学对撞机和准单场结果。在强混合区域，传统转移微扰理论失效，我们发现功率谱和双谱都可以显著增强，从而产生了约化非高斯振幅独特的非微扰标度律。这些结果共同为超越弱耦合近似的多场暴胀打开了一个新的解析窗口，并建立了一个研究宇宙学对撞机信号、原初黑洞产生以及强混合暴胀动力学中的圈修正的框架。
英文摘要
We develop an analytic treatment of primordial non-Gaussianity in multifield inflation that is nonperturbative in the constant curvature--isocurvature mixing strength $λ$. Using exact linear solutions for the coupled curvature perturbation $ζ$ and isocurvature perturbation $σ$, we construct dressed propagators and derive exact integral representations for the tree-level bispectra generated by the interactions $\dotζ^2σ$, $\dotζ\,σ^2$, and $σ^3$. This formalism resums curvature--isocurvature transfer to all orders in $λ$ and applies for arbitrary values of the entropy mass $μ$. We obtain closed-form expressions for the leading squeezed limit of the bispectrum contributions and recover the well-known cosmological-collider and quasi-single-field results in the weak-mixing limit. In the strong-mixing regime, where conventional transfer perturbation theory breaks down, we find that both the power spectrum and the bispectrum can be dramatically enhanced, giving rise to distinctive nonperturbative scaling laws for the reduced non-Gaussian amplitude. Together, these results open a new analytic window onto multifield inflation beyond the weak-coupling approximation and establish a framework for studying cosmological-collider signals, primordial-black-hole production, and loop corrections in strongly mixed inflationary dynamics.
Comments21 pages + appendices + references, 3 figures. v2: Introduced new definition of the f_M solution and added six new plots of the f_NL coefficient for the three interactions
