Large local non-Gaussianity from general ultra slow-roll inflation

We investigate the local non-Gaussian signatures of general ultra slow-roll inflation. The bispectrum and the trispectrum are calculated with general initial conditions. We show that the prediction of local non-Gaussianity is robust against generalizing the Bunch-Davies vacuum in such a model. Even though the bispectrum in this model is tightly constrained by Planck, the trispectrum can still be large enough to be detected by future cosmological observations potentially. We also show that the Suyama-Yamaguchi relation is saturated in this scenario.