Suppressing axion chaos requires a flat inflationary plateau

If the inflaton couples directly to QCD gluons, it can temporarily raise the confinement scale during inflation, making the axion heavy enough to suppress dangerous isocurvature fluctuations — a long-standing obstacle for axion dark matter. Using a single parameter to characterize how the inflaton's slow-roll evolves, the analysis shows that steep monomial potentials cause the confinement scale to grow out of perturbative control, while plateau-like potentials keep the physics tractable. The mechanism also shifts the scalar spectral index toward bluer values, potentially rescuing inflationary models disfavored by current CMB measurements.