Understand
In this paper, we investigate the back-reaction of $U(1)$ gauge fields into a class of inflationary settings.
- To be more precise, we employ a Bianchi-I geometry (taken as an anisotropic perturbation of a flat FRW model) within two types of Born-Infeld theories.
- Firstly we consider pure Born-Infeld electromagnetism.
- For either a constant or a $b(\phi)$ coupling, inflationary trajectories are modified but anisotropies increase; In particular, for the former coupling we find that a quadratic inflaton potential, within a constant ratio for the scalar and gauge energy densities, does not induce sufficient inflation, while in the latter the back-reaction in the cosmology determines (from the tensor-scalar ratio) a narrow range where inflation can occur.