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Title: Magneto-reheating constraints from curvature perturbations

As additional perturbative degrees of freedom, it is known that magnetic fields of inflationary origin can source curvature perturbations on super-Hubble scales. By requiring the magnetic generated curvature to remain smaller than its inflationary adiabatic counterpart during inflation and reheating, we derive new constraints on the maximal field value today, the reheating energy scale and its equation of state parameter. These bounds end up being stronger by a few order of magnitude than those associated with a possible backreaction of the magnetic field onto the background. Our results are readily applicable to any slow-roll single field inflationary models and any magnetic field having its energy density scaling as a{sup γ} during inflation. As an illustrative example, massive inflation is found to remain compatible with a magnetic field today B{sub 0} = 5 × 10{sup −15} G for some values of γ only if a matter dominated reheating takes place at energies larger than 10{sup 5} GeV. Conversely, assuming γ = −1, massive inflation followed by a matter dominated reheating cannot explain large scale magnetic fields larger than 10{sup −20} G today.
Authors:
 [1] ; ;  [2]
  1. Centre for Cosmology, Particle Physics and Phenomenology, Institute of Mathematics and Physics, Louvain University, 2 Chemin du Cyclotron, 1348 Louvain-la-Neuve (Belgium)
  2. Research Center for the Early Universe (RESCEU), Graduate School of Science, The University of Tokyo, Tokyo 113-0033 (Japan)
Publication Date:
OSTI Identifier:
22282676
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Cosmology and Astroparticle Physics; Journal Volume: 2013; Journal Issue: 09; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; COSMOLOGY; DEGREES OF FREEDOM; ENERGY DENSITY; EQUATIONS OF STATE; GEV RANGE; INFLATIONARY UNIVERSE; INFLATONS; LIMITING VALUES; MAGNETIC FIELDS; PERTURBATION THEORY