Description
The primordial magnetic fields are generated during inflation by breaking the conformal invariance of the electromagnetic action through a coupling to the inflaton. Often, a parity violating term is also added to the action to generate helical magnetic fields. In this talk, I will first show that departures from slow roll inflation (as it occurs in scenarios involving a phase of ultra slow roll), which generate strong features in the scalar power spectrum, inevitably lead to sharp features in the power spectra of the electromagnetic fields and also suppress their strengths on large scales. Thereafter, I will illustrate that such challenges can be circumvented in two-field models of inflation to arrive at spectra of magnetic fields of the required strength and shape. Lastly, I will describe the evaluation of the three-point cross-correlation between the curvature perturbations and magnetic fields in slow roll and ultra slow roll inflation, and discuss the validity of the consistency relation in the squeezed limit.
