Cosmological perturbations in Horava-Lifshitz gravity
文献类型：期刊论文
| 作者 | Gao, Xian; Wang, Yi; Brandenberger, R.; Riotto, A.; Gao, X , Chinese Acad Sci, Inst Theoret Phys, Key Lab Frontiers Theoret Phys, Zhong Guan Cun E Rd, Beijing 100080, Peoples R China |
| 刊名 | PHYSICAL REVIEW D
 |
| 出版日期 | 2010 |
| 卷号 | 81期号:8页码:- |
| ISSN号 | 1550-7998 |
| 关键词 | Inflation |
| 英文摘要 | We study cosmological perturbations in Horava-Lifshitz Gravity, a recently proposed potentially ultraviolet-complete quantum theory of gravity. We consider scalar metric fluctuations about a homogeneous and isotropic space-time. Starting from the most general metric, we work out the complete second order action for the perturbations. We then make use of the residual gauge invariance and of the constraint equations to reduce the number of dynamical degrees of freedom. At first glance, it appears that there is an extra scalar metric degree of freedom. However, introducing the Sasaki-Mukhanov variable, the combination of spatial metric fluctuation and matter inhomogeneity for which the action in general relativity has canonical form, we find that this variable has the standard time derivative term in the second order action, and that the extra degree of freedom is nondynamical. The limit lambda -> 1 is well behaved, unlike what is obtained when expanding about Minkowski space-time. Thus, there is no strong coupling problem for Horava-Lifshitz gravity when considering cosmological solutions. We also compute the spectrum of cosmological perturbations. If the potential in the action is taken to be of "detailed balance" form, we find a cancellation of the highest derivative terms in the action for the curvature fluctuations. As a consequence, the initial spectrum of perturbations will not be scale-invariant in a general space-time background, in contrast to what happens when considering Horava-Lifshitz matter leaving the gravitational sector unperturbed. However, if we break the detailed balance condition, then the initial spectrum of curvature fluctuations is indeed scale-invariant on ultraviolet scales. As an application, we consider fluctuations in an inflationary background and draw connections with the "trans-Planckian problem" for cosmological perturbations. In the special case in which the potential term in the action is of detailed balance form and in which lambda = 1, the equation of motion for cosmological perturbations in the far UV takes the same form as in general relativity. However, in general the equation of motion is characterized by a modified dispersion relation. |
| 学科主题 | Physics |
| URL标识 | 查看原文 |
| WOS记录号 | WOS:000277205000025 |
| 公开日期 | 2012-08-02 |
| 源URL | [http://ir.itp.ac.cn/handle/311006/5125]  |
| 专题 | 理论物理研究所_理论物理所1978-2010年知识产出 |
| 通讯作者 | Gao, X , Chinese Acad Sci, Inst Theoret Phys, Key Lab Frontiers Theoret Phys, Zhong Guan Cun E Rd, Beijing 100080, Peoples R China |
| 推荐引用方式 GB/T 7714 | Gao, Xian,Wang, Yi,Brandenberger, R.,et al. Cosmological perturbations in Horava-Lifshitz gravity[J]. PHYSICAL REVIEW D,2010,81(8):-. |
| APA | Gao, Xian,Wang, Yi,Brandenberger, R.,Riotto, A.,&Gao, X , Chinese Acad Sci, Inst Theoret Phys, Key Lab Frontiers Theoret Phys, Zhong Guan Cun E Rd, Beijing 100080, Peoples R China.(2010).Cosmological perturbations in Horava-Lifshitz gravity.PHYSICAL REVIEW D,81(8),-. |
| MLA | Gao, Xian,et al."Cosmological perturbations in Horava-Lifshitz gravity".PHYSICAL REVIEW D 81.8(2010):-. |
入库方式： OAI收割
来源：理论物理研究所
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