Non-Gaussian signatures of multi-field inflation from string theory

多场暴胀模型在弦理论中是很自然的，但是它们的预测是退化的。如果普朗克卫星在宇宙微波背景辐射（CMBR）的波动中观测到非高斯性，则排除了简单的单场模型。因此，消除这种退化是一项最紧迫的任务。多场场景通常包括膨胀期间的附加效应，例如场的衰变或粒子的产生以及相关的反反应。这些效应会导致CMBR波动的高阶相关函数中出现独特的非高斯特征。我们建议使用非高斯性，特别是双光谱和三光谱的形状函数，来识别那些最有可能对暴胀负责的模型。我们计划使用并改进最近提出的保留全形状函数信息的模态分解，并研究模态分解在构建宇宙学模拟初始条件方面的效率。

Multi-field inflationary models are natural in string theory, yet their predictions are degenerate. If non-Gaussianities are observed in fluctuations of the cosmic microwave background radiation (CMBR) by the Planck satellite, simple single-field models are ruled out. Lifting this degeneracy is thus a most pressing task. Multi-field scenarios often include additional effects during inflation, such as the decay of fields or particle production and the associated backreaction. These effects can lead to unique, non-Gaussian signatures in higher order correlation functions of fluctuations in the CMBR. We propose to use non-Gaussianities, especially the shape function of the bi- and trispectrum, to identify those models that are most likely responsible for inflation. We plan to use and improve upon a recently proposed mode decomposition retaining information of the full shape function and investigate the efficiency of the mode decomposition for constructing initial conditions for cosmological simulations.