Chinese Acad Sci, Inst High Energy Phys, Beijing 100039, Peoples R China
; Chinese Acad Sci, Interdisciplinary Ctr Theoret Studies, Beijing 100080, Peoples R China
The Universe might experience many cycles with different vacua. The slow-roll inflation may be preceded by kinetic-dominated contraction occurring in "adjacent" vacua during some cycles. In this report we briefly show this phenomenon may lead to a cutoff of primordial power spectrum, which is mildly preferred by WMAP data. Thus in some sense the cosmic microwave background at large angular scale might encode the information of other vacua.