Abstract. We investigate the primordial non-Gaussianities from the trispectra in multi-field inflation models, which can be seen as generalization of multi-field k-inflation and multi-DBI inflation. We derive the full fourth-order perturbation action for the inflaton fields and evaluate the four-point correlation functions for the perturbations in the limit c_a << 1 and c_e << 1. There are three types of momentum-dependent shape functions which arise from three types of four-point interaction vertices. The final trispectrum of the curvature perturbation can be expressed in terms of the deformations and permutations of these three shape functions, and is determined by c_a, c_e, λ , Π which depend on the non-linear structure of the model and also the transfer function T. We also discuss the parameter space for the trispectrum and plot the shape diagrams for the trispectrum both for visualization and for distinguishing different shapes from each other.

Key words: cosmological perturbation theory; physics of the early universe; non-gaussianity

E-print number: 0906.1345
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Received 18 June 2009, accepted for publication 6 October 2009
Published 5 November 2009