Modified Lyth bound and implications of BICEP2 results

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	Modified Lyth bound and implications of BICEP2 results
	Gao, Q; Gong, YG; Li, TJ
刊名	PHYSICAL REVIEW D
	2015
卷号	91 期号:6 页码:63509
通讯作者	Gong, YG (reprint author), Huazhong Univ Sci & Technol, Sch Phys, MOE Key Lab Fundamental Quant Measurement, Wuhan 430074, Peoples R China.
英文摘要	To reconcile the BICEP2 measurement on the tensor-to-scalar ratio r with Planck constraint, a large negative running of scalar spectral index n(s) is needed. So the inflationary observable such as ns should be expanded at least to the second-order slow-roll parameters for single-field inflationary models. The large value of r and the Lyth bound indicate that it is impossible to obtain the sub-Planckian excursion for the inflaton. However, we derive an absolutely minimal bound Delta phi/M-PI > root r/2 on the inflaton excursion for single-field inflationary models, which can be applied to non-slow-roll inflationary models as well. This bound excludes the possibility of the small-field inflation with Delta phi < 0.1M(P1) if the BICEP2 result on r stands, and it opens the window of sub-Planckian excursion with Delta phi < M-P1, even if r is as large as 0.1. To get the sub-Planckian excursion with Delta phi < 0.1M(P1), our modified bound requires r < 0.02. Using a fifth-order polynomial potential as an explicit example, we show that it not only agrees with the observational results, but also violates the Lyth bound.
学科主题	Astronomy & Astrophysics ; Physics
类目[WOS]	Astronomy & Astrophysics ; Physics, Particles & Fields
关键词[WOS]	SINGLE FIELD INFLATION ; NO-SCALE SUPERGRAVITY ; CHAOTIC INFLATION ; DENSITY PERTURBATION ; GRAVITATIONAL-WAVE ; HYBRID INFLATION ; POWER SPECTRUM ; PLANCK ; MODELS ; UNIVERSE
收录类别	SCI
语种	英语
内容类型	期刊论文
源URL	[http://ir.itp.ac.cn/handle/311006/21067]
专题	理论物理研究所_理论物理所1978-2010年知识产出
推荐引用方式 GB/T 7714	Gao, Q,Gong, YG,Li, TJ. Modified Lyth bound and implications of BICEP2 results[J]. PHYSICAL REVIEW D,2015,91(6):63509.
APA	Gao, Q,Gong, YG,&Li, TJ.(2015).Modified Lyth bound and implications of BICEP2 results.PHYSICAL REVIEW D,91(6),63509.
MLA	Gao, Q,et al."Modified Lyth bound and implications of BICEP2 results".PHYSICAL REVIEW D 91.6(2015):63509.