Evolution of axions in the presence of primordial magnetic fields

Abstract

We study the evolution of axions interacting with primordial magnetic fields (PMFs) starting just from the QCD phase transition in the expanding universe. This interaction is owing to the Primakoff effect. Adopting the zero mode approximation for axions, we derive the system of equations for axions and magnetic fields, where the expansion of the universe and the spectra of magnetic fields are accounted for exactly. We find that the contribution of the Primakoff effect to the dynamics of axions and magnetic fields is rather weak. It confirms some previous estimates leading to analogous conclusions, when accounting here for the Hubble expansion both for an uniform axion field and non-uniform PMFs using Fourier spectra for their energy and helicity densities. We solve the corresponding system of the evolution equations and find that the axion zero mode, when evolving during radiation era, has its amplitude at the level sufficient for that axion to be a good candidate for the cold dark matter.

8 pages in Revtex, 4 eps figures; accepted for publication in Phys.Rev.D

References in corpus (4)

• Evolution of Primordial Magnetic Fields from Phase Transitions
• Evolution of hydromagnetic turbulence from the electroweak phase transition
• Axions: Bose Einstein Condensate or Classical Field?
• Implications of a Primordial Magnetic Field for Magnetic Monopoles, Axions, and Dirac Neutrinos

Cited by in corpus (7)

• Dipole Radiation and Beyond from Axion Stars in Electromagnetic Fields
• Relativistic spin dynamics conditioned by dark matter axions
• Interaction of inhomogeneous axions with magnetic fields in the early universe
• Impact of Helical Electromagnetic Fields on the Axion Window
• Magnetic fields in inhomogeneous axion stars
• Low mode approximation in the axion magnetohydrodynamics
• Evolution of Mirror Axion Solitons