Full quantum trispectrum in multifield DBI inflation

Shuntaro Mizuno, Frederico Arroja, Kazuya Koyama

研究成果: Article

33 引用 (Scopus)


We compute the leading order connected four-point function of the primordial curvature perturbation coming from the four-point function of the fields in multifield DBI-inflation models. We confirm that the consistency relations in the squeezed limit and in the counter-collinear limit hold as in single-field models thanks to special properties of the DBI action. We also study the momentum dependence of the trispectra coming from the adiabatic, mixed and purely entropic contributions separately and we find that they have different momentum dependence. This means that if the amount of the transfer from the entropy perturbations to the curvature perturbation is significantly large, the trispectrum can distinguish multifield DBI-inflation models from single-field DBI-inflation models. A large amount of transfer TRS□1 suppresses the tensor-to-scalar ratio r□TRS-2 and the amplitude of the bispectrum fNLequi□TRS-2 and so it can ease the severe observational constraints on the DBI-inflation model based on string theory. On the other hand, it enhances the amplitude of the trispectrum τNLequi□TRS2fNLequi2 for a given amplitude of the bispectrum.

ジャーナルPhysical Review D - Particles, Fields, Gravitation and Cosmology
出版物ステータスPublished - 2009 10 15

ASJC Scopus subject areas

  • Nuclear and High Energy Physics

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