Large non-Gaussianity in multiple-field inflation
Large non-Gaussianity in multiple-field inflation
复制标题
多场膨胀中的大非高斯性
DOI：
10.1103/physrevd.73.083522
复制
发表时间：
2005
影响因子：
5
通讯作者：
B. Tent
中科院分区：
文献类型：
--
作者：
G. Rigopoulos;E. Shellard;B. Tent
我们使用我们在早期论文中开发的形式主义来研究一般多场膨胀中的非高斯性。我们使用非线性方程的微扰展开来解析计算曲率微扰的三点相关器。我们推导出一个仅涉及背景时间积分和线性扰动量的通用表达式。我们针对两场慢滚情况明确地计算出该表达式，并发现非高斯性可以比单场情况大几个数量级。特别是，双谱除以功率谱的平方很容易得到 $\mathcal{O}(1--10)$，具体取决于模型。我们的结果还显示了双谱的明确动量依赖性。这一大非高斯性的结论在简单二次双场模型的半解析研究中得到了证实。
We investigate non-Gaussianity in general multiple-field inflation using the formalism we developed in earlier papers. We use a perturbative expansion of the nonlinear equations to calculate the three-point correlator of the curvature perturbation analytically. We derive a general expression that involves only a time integral over background and linear perturbation quantities. We work out this expression explicitly for the two-field slow-roll case, and find that non-Gaussianity can be orders of magnitude larger than in the single-field case. In particular, the bispectrum divided by the square of the power spectrum can easily be of $\mathcal{O}(1--10)$, depending on the model. Our result also shows the explicit momentum dependence of the bispectrum. This conclusion of large non-Gaussianity is confirmed in a semianalytic investigation of a simple quadratic two-field model.