Evolution of fNL to the adiabatic limit
Evolution of fNL to the adiabatic limit
复制标题
fNL 演化至绝热极限
DOI：
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发表时间：
2011
期刊：
影响因子：
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通讯作者：
R. Tavakol
中科院分区：
文献类型：
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作者：
Joseph Elliston;D. Mulryne;D. Seery;R. Tavakol
我们研究了多场模型中的暴胀扰动，这种暴胀扰动通常会演化到所有等曲率模式衰减-绝热极限。我们使用数值方法来探索局部形状的双谱的敏感性的过程中，实现这一限制，发现一个明显的依赖模型的具体数据，如在慢辊故障或再加热的时间尺度的时间。在模型的总和可分离的潜在的isocurvature模式衰减之前的慢滚阶段结束时，我们给出了一个分析标准的渐近值fNL是大的。其他例子可以使用瀑布场来终止暴胀，而fNL是瞬时大的，由从山脊下降或收敛到山谷引起。我们表明，这两种类型的演变区分的符号的双谱，并给出近似表达式的峰值fNL。
We study inflationary perturbations in multiple-field models, for which ζ typically evolves until all isocurvature modes decay — the adiabatic limit. We use numerical methods to explore the sensitivity of the local-shape bispectrum to the process by which this limit is achieved, finding an appreciable dependence on model-specific data such as the time at which slow-roll breaks down or the timescale of reheating. In models with a sum-separable potential where the isocurvature modes decay before the end of the slow-roll phase we give an analytic criterion for the asymptotic value of fNL to be large. Other examples can be constructed using a waterfall field to terminate inflation while fNL is transiently large, caused by descent from a ridge or convergence into a valley. We show that these two types of evolution are distinguished by the sign of the bispectrum, and give approximate expressions for the peak fNL.
影响因子：
4.4
作者：
Adam J. Christopherson;Karim A. Malik
通讯作者：
Adam J. Christopherson;Karim A. Malik