Effective treatment of U(1) gauge field and charged particles in axion inflation

Tomohiro Fujita, Jun'ya Kume, Kyohei Mukaida, Yuichiro Tada

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)


The axionic inflaton with the Chern-Simons coupling may generate U(1) gauge fields and charged particles simultaneously. In order to incorporate the backreaction from the charged particles on the gauge fields, we develop a procedure to obtain an equilibrium solution for the gauge fields by treating the induced current as effective electric and magnetic conductivities. Introducing mean field approximation, and numerically solving self-consistency equations, we find that the gauge field amplitudes are drastically suppressed. Interestingly, as the production becomes more efficient, the charged particles gain a larger part of the transferred energy from the inflaton and eventually dominate it. Our formalism offers a basis to connect this class of inflationary models to a rich phenomenology such as baryogenesis and magnetogenesis.

Original languageEnglish
Article number023
JournalJournal of Cosmology and Astroparticle Physics
Issue number9
Publication statusPublished - 2022 Sept 1


  • inflation
  • particle physics - cosmology connection
  • primordial magnetic fields

ASJC Scopus subject areas

  • Astronomy and Astrophysics


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