Exploring the Parameter Space of Warm-Inflation Models

Mar Bastero-Gil, Arjun Berera, Nico Kronberg

Research output: Contribution to journalArticlepeer-review


Warm inflation includes inflaton interactions with other fields throughout the inflationary epoch instead of confining such interactions to a distinct reheating era. Previous investigations have shown that, when certain constraints on the dynamics of these interactions and the resultant radiation bath are satisfied, a low-momentum-dominated dissipation coefficient $\propto T^3/m_\chi^2$ can sustain an era of inflation compatible with CMB observations. In this work, we extend these analyses by including the pole-dominated dissipation term $\propto \sqrt{m_\chi T} \exp(-m_\chi/T)$. We find that, with this enhanced dissipation, certain models, notably the quadratic hilltop potential, perform significantly better. Specifically, we can achieve 50 e-folds of inflation and a spectral index compatible with Planck data while requiring fewer mediator field ($O(10^4)$ for the quadratic hilltop potential) and smaller coupling constants, opening up interesting model-building possibilities. We also highlight the significance of the specific parametric dependence of the dissipative coefficient which could prove useful in even greater reduction in field content.
Original languageUndefined/Unknown
JournalJournal of Cosmology and Astroparticle Physics (JCAP)
Publication statusPublished - 25 Sep 2015


  • hep-ph
  • astro-ph.CO

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