Primordial magnetic fields from a non-singular bouncing cosmology

Understand

Although inflation is a natural candidate to generate the lengths of coherence of magnetic fields needed to explain current observations, it needs to break conformal invariance of electromagnetism to obtain significant magnetic amplitudes.

• Of the simplest realizations are the kinetically-coupled theories $f^2(\phi)F_{\mu\nu}F^{\mu\nu}$ (or $IFF$ theories).
• However, these are known to suffer from electric fields backreaction or the strong coupling problem.
• In this work we shall confirm that such class of theories are problematic to support magnetogenesis during inflationary cosmology.