The isotropic attractor solution of axion-SU(2) inflation: Universal isotropization in Bianchi type-I geometry

Ira Wolfson, Azadeh Maleknejad, Tomoaki Murata, Eiichiro Komatsu, Tsutomu Kobayashi

Research output: Contribution to journalArticlepeer-review

7 Scopus citations

Abstract

SU(2) gauge fields coupled to an axion field can acquire an isotropic background solution during inflation. We study homogeneous but anisotropic inflationary solutions in the presence of such (massless) gauge fields. A gauge field in the cosmological background may pose a threat to spatial isotropy. We show, however, that such models generally isotropize in Bianchi type-I geometry, and the isotropic solution is the attractor. Restricting the setup by adding an axial symmetry, we revisited the numerical analysis presented in [1]. We find that the reported numerical breakdown in the previous analysis is an artifact of parametrization singularity. We use a new parametrization that is well-defined all over the phase space. We show that the system respects the cosmic no-hair conjecture and the anisotropies always dilute away within a few e-folds.

Original languageEnglish
Article number031
JournalJournal of Cosmology and Astroparticle Physics
Volume2021
Issue number9
DOIs
StatePublished - 1 Sep 2021
Externally publishedYes

Keywords

  • axions
  • inflation
  • particle physics-cosmology connection
  • quantum cosmology

ASJC Scopus subject areas

  • Astronomy and Astrophysics

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