Primordial magnetic fields in theories of gravity with non-minimal coupling between curvature and matter

The existence of magnetic fields in the universe is unmistakable. They are observed at all scales from stars to galaxy clusters. However, the origin of these fields remains enigmatic. It is believed that magnetic field seeds may have emerged from inflation, under certain conditions. This possibility is analised in the context of an alternative theory of gravity with non-minimal coupling between curvature and matter. We find, through the solution of the generalised Maxwell equations in the context of non-minimal models, that for general slow-roll inflationary scenarios with low reheating temperatures, T-RH similar or equal to 10(10) GeV, the generated magnetic fields can be made compatible with observations at large scales, lambda similar to 1Mpc.

Automated summary

The existence of magnetic fields in the universe is observed at all scales, but their origin remains unknown. In the context of non-minimal coupling gravity theory, it is found that under certain conditions, the generated magnetic fields during inflation can be compatible with large-scale observations.