Trispectrum from Ghost Inflation
  Ghost inflation predicts almost scale-invariant primordial cosmological
perturbations with relatively large non-Gaussianity. The bispectrum is known to
have a large contribution at the wavenumbers forming an equilateral triangle
and the corresponding nonlinear parameter $f_{NL}^{equil}$ is typically of
order $O(10^2)$. In this paper we calculate trispectrum from ghost inflation
and show that the corresponding nonlinear parameter $\tau_{NL}$ is typically of
order $O(10^4)$. We investigate the shape dependence of the trispectrum and see
that it has some features different from DBI inflation. Therefore, our result
may be useful as a template to distinguish ghost inflation from other models of
inflation by future experiments.
