Super-horizon resonant magnetogenesis during inflation

Understand

We propose a novel mechanism for significantly enhancing the amplitude of primordial electromagnetic fields during inflation.

• Similar to existing proposals, our idea is based on parametric resonance effects due to conformal-symmetry-breaking coupling of a gauge field and the inflaton.
• Our proposed scenario, however, significantly differs from previously studied models, and avoids their shortcomings.
• We, particularly, construct a viable system where the gauge field is exponentially amplified on super-horizon scales, therefore evading the no-go theorem formulated on the basis of widely encountered drastic back-reaction of the magnetic field energy on the inflationary background.