Stealth magnetic field in de Sitter spacetime

Abstract

In the context of a U(1) gauge theory non-minimally coupled to scalar-tensor gravity, we find a cosmological attractor solution that represents a de Sitter universe with a homogeneous magnetic field. The solution fully takes into account backreaction of the magnetic field to the geometry and the scalar field. Such a solution is made possible by scaling-type global symmetry and fine-tuning of two parameters of the theory. If the fine-tuning is relaxed then the solution is deformed to an axisymmetric Bianchi type-I universe with constant curvature invariants, a homogeneous magnetic field and a homogeneous electric field. Implications to inflationary magnetogenesis are briefly discussed.

10 pages; expanded discussion about implications to inflationary magnetogenesis, including the amplitude today, observational constraint, statistical anisotropy, etc (v2); version accepted for publication as a Rapid Communication in Physical Review D (v3)

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Cited by in corpus (2)

• Effect of a magnetic field on Schwinger mechanism in de Sitter spacetime
• Primordial magnetic helicity evolution with a homogeneous magnetic field from inflation