Inflation with multiple sound speeds: A model of multiple DBI type actions and non-Gaussianities

	Inflation with multiple sound speeds: A model of multiple DBI type actions and non-Gaussianities
	Cai YF(蔡一夫); Cai, YF; Xia, HY
刊名	PHYSICS LETTERS B
	2009
卷号	677 期号:5 页码:#REF!
通讯作者	Cai, YF (reprint author), Chinese Acad Sci, Inst High Energy Phys, POB 918-4, Beijing 100049, Peoples R China.
英文摘要	In this Letter we study adiabatic and isocurvature perturbations in the frame of inflation with multiple sound speeds involved. We suggest this scenario can be realized by a number of generalized scalar fields with arbitrary kinetic forms. These scalars have their own sound speeds respectively, so the propagations of field fluctuations are individual. Specifically, we study a model constructed by two DBI type actions. We find that the critical length scale for the freezing of perturbations corresponds to the maximum sound horizon. Moreover, if the mass term of one field is much lighter than that of the other, the entropy perturbation could be quite large and so may give rise to a growth outside sound horizon. At cubic order, we find that the non-Gaussianity of local type is possibly large when entropy perturbations are able to convert into curvature perturbations. We also calculate the non-Gaussianity of equilateral type approximately. (C) 2009 Elsevier B.V. All rights reserved.
学科主题	Physics
类目[WOS]	Physics, Multidisciplinary
收录类别	SCI
WOS记录号	WOS:000267729900002
公开日期	2016-05-03
内容类型	期刊论文
源URL	[http://ir.ihep.ac.cn/handle/311005/227055]
专题	高能物理研究所_理论物理室
推荐引用方式 GB/T 7714	Cai YF,Cai, YF,Xia, HY. Inflation with multiple sound speeds: A model of multiple DBI type actions and non-Gaussianities[J]. PHYSICS LETTERS B,2009,677(5):#REF!.
APA	蔡一夫,Cai, YF,&Xia, HY.(2009).Inflation with multiple sound speeds: A model of multiple DBI type actions and non-Gaussianities.PHYSICS LETTERS B,677(5),#REF!.
MLA	蔡一夫,et al."Inflation with multiple sound speeds: A model of multiple DBI type actions and non-Gaussianities".PHYSICS LETTERS B 677.5(2009):#REF!.