期刊
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
卷 -, 期 6, 页码 -出版社
IOP PUBLISHING LTD
DOI: 10.1088/1475-7516/2009/06/035
关键词
inflation; non-gaussianity; cosmological perturbation theory
资金
- Ministry of Education, Science & Technology (MoST), Republic of Korea [MG028801] Funding Source: Korea Institute of Science & Technology Information (KISTI), National Science & Technology Information Service (NTIS)
In this paper we mainly focus on the curvature perturbation generated at the end of multi-field inflation, such as the multi-brid inflation. Since the curvature perturbation is produced on the super-horizon scale, the bispectrum and trispectrum have a local shape. The size of bispectrum is measured by f(NL) and the trispectrum is characterized by two parameters tau(NL) and g(NL). For simplicity, the trajectory of inflaton is assumed to be a straight line in the field space and then the entropic perturbations do not contribute to the curvature perturbation during inflation. As long as the background inflaton path is not orthogonal to the hyper-surface for inflation to end, the entropic perturbation can make a contribution to the curvature perturbation at the end of inflation and a large local-type non-Gaussiantiy is expected. An interesting thing is that the non-Gaussianity parameters are completely determined by the geometric properties of the hyper-surface of the end of inflation. For example, f(NL) is proportional to the curvature of the curve on this hyper-surface along the adiabatic direction and g(NL) is related to the change of the curvature radius per unit arc-length of this curve. Both f(NL) and g(NL) can be positive or negative respectively, but tau(NL) must be positive and not less than (6/5f(NL))(2).
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据