Natural and multi-natural inflation in axion landscape

Tetsutaro Higaki, Fuminobu Takahashi

Research output: Contribution to journalArticlepeer-review

66 Citations (Scopus)


We propose a landscape of many axions, where the axion potential receives various contributions from shift symmetry breaking effects. We show that the existence of the axion with a super-Planckian decay constant is very common in the axion landscape for a wide range of numbers of axions and shift symmetry breaking terms, because of the accidental alignment of axions. The effective inflation model is either natural or multi-natural inflation in the axion landscape, depending on the number of axions and the shift symmetry breaking terms. The tension between BICEP2 and Planck could be due to small modulations to the inflaton potential or steepening of the potential along the heavy axions after the tunneling. The total duration of the slow-roll inflation our universe experienced is not significantly larger than 60 if the typical height of the axion potentials is of order (1016-17 GeV)4.

Original languageEnglish
Article number74
JournalJournal of High Energy Physics
Issue number7
Publication statusPublished - 2014 Jul
Externally publishedYes


  • Cosmology of Theories beyond the SM
  • Flux compactifications
  • Superstring Vacua

ASJC Scopus subject areas

  • Nuclear and High Energy Physics


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