Huang, QG (reprint author), Chinese Acad Sci, Inst Theoret Phys, State Key Lab Theoret Phys, Beijing 100190, Peoples R China.
文章类型:
Article
英文摘要:
Imposing that the excursion distance of the inflaton in field space during inflation be less than the Planck scale, we derive an upper bound on the tensor-to-scalar ratio at the cosmic microwave background scales, i.e., r(*),(max), in the general canonical single-field slow-roll inflation model, in particular, the model with non-negligible running of the spectral index alpha(s) and/or the running of running beta(s). We find that r(*),(max) similar or equal to 7 x 10(-4) for n(s) = 0.9645 without running and running of running, and r(*),(max) is significantly relaxed to the order of O(10(-2) similar to 10(-1)) in the inflation model with alpha(s) and/or beta(s) similar to + O(10(-2)) which are marginally preferred by the Planck 2015 data.
