Primordial black holes from thermal inflation

Konstantinos Dimopoulos*, Tommi Markkanen, Antonio Racioppi, Ville Vaskonen

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

10 Citations (Scopus)


We present a novel mechanism for the production of primordial black holes (PBHs). The mechanism is based on a period of thermal inflation followed by fast-roll inflation due to tachyonic mass of order the Hubble scale. Large perturbations are generated at the end of the thermal inflation as the thermal inflaton potential turns from convex to concave. These perturbations can lead to copious production of PBHs when the relevant scales re-enter horizon. We show that such PBHs can naturally account for the observed dark matter in the Universe when the mass of the thermal inflaton is about 106GeV and its coupling to the thermal bath preexisting the late inflation is of order unity. We consider also the possibility of forming the seeds of the supermassive black holes. In this case we find that the mass of the thermal inflaton is about 1 GeV, but its couplings have to be very small, 10-7. Finally we study a concrete realisation of our mechanism through a running mass model.

Original languageEnglish
Article number046
JournalJournal of Cosmology and Astroparticle Physics
Issue number7
Publication statusPublished - 31 Jul 2019


  • inflation
  • primordial black holes


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