Gravitational waves from a curvaton model with blue spectrum
  We investigate the gravitational wave background induced by the first order
scalar perturbations in the curvaton models. We consider the quadratic and
axion-like curvaton potential which can generate the blue-tilted power spectrum
of curvature perturbations on small scales and derive the maximal amount of
gravitational wave background today. We find the power spectrum of the induced
gravitational wave background has a characteristic peak at the frequency
corresponding to the scale reentering the horizon at the curvaton decay, in the
case where the curvaton does not dominate the energy density of the Universe.
We also find the enhancement of the amount of the gravitational waves in the
case where the curvaton dominates the energy density of the Universe. Such
induced gravitational waves would be detectable by the future space-based
gravitational wave detectors or pulsar timing observations.
