发表机构
The University of Osaka; University of Fukui（大阪大学; 福井大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文针对量子扩散主导的多场暴胀模型，提出基于蒙特卡罗的压缩极限双谱计算方法，验证了其在单、双场混沌暴胀中的适用性，并首次计算带弱瀑布的混合暴胀的双谱。
AI 中文摘要
宇宙学扰动的双谱是探测暴胀及 underlying 粒子物理的重要探针。然而，在暴胀子动力学由量子扩散而非慢滚主导的暴胀模型中，尤其是多场情形，计算双谱极具挑战性。本文采用随机-δ𝒩形式体系，提出一种基于蒙特卡罗的方法，用于计算压缩极限下的双谱，该方法是我们此前提出的功率谱计算方法的延伸。我们的方法仅生成暴胀子时间演化的分支路径，分支次数有限，避免了嵌套路径生成（嵌套路径生成会带来过高的计算成本）。作为数值示例，我们将该方法应用于单场和双场混沌暴胀以进行验证，还应用于带有弱瀑布的混合暴胀，据我们所知，这是首次计算该模型的双谱。
英文摘要
The bispectrum of cosmological perturbations is an important probe of inflation and the underlying particle physics. However, calculating it becomes challenging in inflation models where inflaton dynamics is dominated by quantum diffusion rather than slow-roll, especially in the multi-field case. In this paper, employing the stochastic-$δ\mathcal{N}$ formalism, we propose a Monte Carlo-based method to calculate the bispectrum in the squeezed limit, as an extension of the method for the power spectrum that we previously proposed. Our method involves generating paths of inflatons' time evolution that branch only several times, avoiding nested path generation, which incurs a prohibitive computational cost. As numerical demonstrations, we apply the proposed method to single- and double-field chaotic inflation for validation, and to hybrid inflation with mild waterfall, for which, to the best of our knowledge, the bispectrum is calculated for the first time in this work.
Comments21 pages, 6 figures
