Constraints on small-field axion inflation

Tatsuo Kobayashi*, Akane Oikawa, Naoya Omoto, Hajime Otsuka, Ikumi Saga

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    5 Citations (Scopus)


    We study general class of small-field axion inflations, which are the mixture of polynomial and sinusoidal functions suggested by the natural and axion monodromy inflations. The axion decay constants leading to the successful axion inflations are severely constrained in order not to spoil the big bang nucleosynthesis and overproduce the isocurvature perturbation originating from the QCD axion. We in turn find that the cosmologically favorable axion decay constants are typically of order the grand unification scale or the string scale, which is consistent with the prediction of closed-string axions.

    Original languageEnglish
    Article number063514
    JournalPhysical Review D
    Issue number6
    Publication statusPublished - 2017 Mar 14

    ASJC Scopus subject areas

    • Physics and Astronomy (miscellaneous)


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