Metric-torsion preheating: cosmic dynamo mechanism?
  Earlier Bassett et al [Phys Rev D 63 (2001) 023506] investigated the
amplification of large scale magnetic fields during preheating and inflation in
several different models. They argued that in the presence of conductivity
resonance effect is weakened. From a dynamo equation in spacetimes endowed with
torsion recently derived by Garcia de Andrade [Phys Lett B 711: 143 (2012)] it
is shown that a in a universe with pure torsion in Minkowski spacetime the
cosmological magnetic field is enhanced by ohmic or non-conductivity effect,
which shows that the metric-torsion effects is worth while of being studied. In
this paper we investigated the metric-torsion preheating perturbation, which
leads to the seed cosmological magnetic field in the universe with torsion is
of the order of $B_{seed}\sim{10^{-37}Gauss}$ which is several orders of
magnitude weaker than the decoupling value obtained from pure metric preheating
of $10^{-15}Gauss$. Despite of the weakness of the magnetic field this seed
field may seed the galactic dynamo.
