Stability analysis of inflation with an SU(2) gauge field

Keiichi Maeda, Kei Yamamoto

    Research output: Contribution to journalArticle

    11 Citations (Scopus)

    Abstract

    We study anisotropic cosmologies of a scalar field interacting with an SU(2) gauge field via a gauge-kinetic coupling. We analyze Bianchi class A models, which include Bianchi type I, II, VI0, VII0, VIII and IX. The linear stability of isotropic inflationary solution with background magnetic field is shown, which generalizes the known results for U(1) gauge fields. We also study anisotropic inflationary solutions, all of which turn out to be unstable. Then nonlinear stability for the isotropic inflationary solution is examined by numerically investigating the dependence of the late-time behaviour on the initial conditions. We present a number of novel features that may well affect physical predictions and viability of the models. First, in the absence of spatial curvature, strong initial anisotropy leads to a rapid oscillation of gauge field, thwarting convergence to the inflationary attractor. Secondly, the inclusion of spatial curvature destabilizes the oscillatory attractor and the global stability of the isotropic inflation with gauge field is restored. Finally, based on the numerical evidence combined with the knowledge of the eigenvalues for various inflationary solutions, we give a generic lower-bound for the duration of transient anisotropic inflation, which is inversely proportional to the slow-roll parameter.

    Original languageEnglish
    Article number018
    JournalJournal of Cosmology and Astroparticle Physics
    Volume2013
    Issue number12
    DOIs
    Publication statusPublished - 2013 Dec

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    curvature
    viability
    eigenvalues
    inclusions
    scalars
    oscillations
    anisotropy
    kinetics
    predictions
    magnetic fields

    Keywords

    • cosmology of theories beyond the SM
    • ination

    ASJC Scopus subject areas

    • Astronomy and Astrophysics

    Cite this

    Stability analysis of inflation with an SU(2) gauge field. / Maeda, Keiichi; Yamamoto, Kei.

    In: Journal of Cosmology and Astroparticle Physics, Vol. 2013, No. 12, 018, 12.2013.

    Research output: Contribution to journalArticle

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