Curvaton as dark matter with secondary inflation

Jinn Ouk Gong, Naoya Kitajima, Takahiro Terada

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8 Scopus citations


We consider a novel cosmological scenario in which a curvaton is long-lived and plays the role of cold dark matter (CDM) in the presence of a short, secondary inflation. Non-trivial evolution of the large scale cosmological perturbation in the curvaton scenario can affect the duration of the short term inflation, resulting in the inhomogeneous end of inflation. Non-linear parameters of the curvature perturbation are predicted to be fNL,5/4 and gNL 0. The curvaton abundance can be well diluted by the short-term inflation and accordingly, it does not have to decay into the Standard Model particles. Then the curvaton can account for the present CDM with the isocurvature perturbation being sufficiently suppressed because both the adiabatic and CDM isocurvature perturbations have the same origin. As an explicit example, we consider the thermal inflation scenario and a string axion as a candidate for this curvaton-dark matter. We further discuss possibilities to identify the curvaton-dark matter with the QCD axion.

Original languageEnglish
Article number053
JournalJournal of Cosmology and Astroparticle Physics
Issue number3
StatePublished - 27 Mar 2017

Bibliographical note

Funding Information:
TT is partially supported by the Grant-in-Aid for JSPS Fellows and the Grant-in-Aid for Scientific Research on Scientific Research No. 26-10619, and by National Research Foundation of Korea (NRF) Research Grant NRF-2015R1A2A1A05001869. A part of TT's work was done when he belonged to APCTP.

Publisher Copyright:
© 2017 IOP Publishing Ltd and Sissa Medialab srl .


  • cosmological perturbation theory
  • physics of the early universe


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