Inflation from a Supersymmetric Axion Model
  We show that a supersymmetric axion model naturally induces a hybrid
inflation with the waterfall field identified as a Peccei-Quinn scalar. The
Peccei-Quinn scale is predicted to be around 10^{15}GeV for reproducing the
large-scale density perturbation of the Universe. After the built-in late-time
entropy-production process, the axion becomes a dark matter candidate. Several
cosmological implications are discussed.
