How attractive is the isotropic attractor solution of axion-SU(2) inflation?

Understand

The key to the phenomenological success of inflation models with axion and SU(2) gauge fields is the isotropic background of the SU(2) field.

• Previous studies showed that this isotropic background is an attractor solution during inflation starting from anisotropic (Bianchi Type I) spacetime; however, not all possible initial anisotropic parameter space was explored.
• In this paper, we explore more generic initial conditions without assuming the initial slow-roll dynamics.
• We find some initial anisotropic parameter space which does not lead to the isotropic background, but to violation of slow-roll conditions, terminating inflation prematurely.