Large-scale magnetic fields from inflation in teleparallel gravity
  Generation of large-scale magnetic fields in inflationary cosmology is
studied in teleparallelism, where instead of the scalar curvature in general
relativity, the torsion scalar describes the gravity theory. In particular, we
investigate a coupling of the electromagnetic field to the torsion scalar
during inflation, which leads to the breaking of conformal invariance of the
electromagnetic field. We demonstrate that for a power-law type coupling, the
current magnetic field strength of $\sim 10^{-9}$ G on 1 Mpc scale can be
generated, if the backreaction effects and strong coupling problem are not
taken into consideration.
