Axion isocurvature fluctuations with extremely blue spectrum
  We construct an axion model for generating isocurvature fluctuations with
blue spectrum, n_{iso}=2-4, which is suggested by recent analyses of admixture
of adiabatic and isocurvature perturbations with independent spectral indices,
n_{ad} \ne n_{iso}. The distinctive feature of the model is that the spectrum
is blue at large scales while scale invariant at small scales. This is
naturally realized by the dynamics of the Peccei-Quinn scalar field.
