Backreaction of axion-SU(2) dynamics during inflation

Understand

We consider the effects of backreaction on axion-SU(2) dynamics during inflation.

• We use the linear evolution equations for the gauge field modes and compute their backreaction on the background quantities numerically using the Hartree approximation.
• We show that the spectator chromo-natural inflation attractor is unstable when back-reaction becomes important.
• Working within the constraints of the linear mode equations, we find a new dynamical attractor solution for the axion field and the vacuum expectation value of the gauge field, where the latter has an opposite sign with respect to the chromo-natural inflation solution.