Effects of Radiation on Primordial Non-Gaussianity
  We study the non-Gaussian features in single-field slow-roll inflationary
scenario where inflation is preceded by a radiation era. In such a scenario
both bispectrum and trispectrum non-Gaussianities are enhanced. Interestingly,
the trispectrum in this scenario does not depend up on the slow-roll parameters
and thus $\tau_{NL}$ is larger than $f_{NL}$ which can be a signature of such a
pre-inflationary radiation era.
