Testing the Origin of Cosmological Magnetic Fields through the   Large-Scale Structure Consistency Relations
  We study the symmetries of the post-recombination cosmological magnetohydrodynamical equations which describe the evolution of dark matter, baryons and magnetic fields in a self-consistent way. This is done both at the level of fluid equations and of Vlasov-Poisson-Maxwell equations in phase space. We discuss some consistency relations for the soft limit of the (n + 1)-correlator functions involving magnetic fields and matter overdensities. In particular, we stress that any violation of such consistency relations at equal-time would point towards an inflationary origin of the magnetic field. 
P. Berger, A. Kehagias, and A. Riotto (Univ. of Geneva)
astro-ph.CO gr-qc hep-ph hep-th