Full quantum trispectrum in multifield DBI inflation

Journal Article · Thu Oct 15 04:00:00 EDT 2009 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PHYSREVD.80.083517· OSTI ID:21325327

Mizuno, Shuntaro ^[1]; Arroja, Frederico ^[2]; Koyama, Kazuya ^[3]

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1. School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD (United Kingdom)
2. Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502 (Japan)
3. Institute of Cosmology and Gravitation, University of Portsmouth, Portsmouth PO1 3FX (United Kingdom)

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 T{sub RS}>>1 suppresses the tensor-to-scalar ratio r{proportional_to}T{sub RS}{sup -2} and the amplitude of the bispectrum f{sub NL}{sup equi}{proportional_to}T{sub RS}{sup -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 {tau}{sub NL}{sup equi}{proportional_to}T{sub RS}{sup 2}f{sub NL}{sup equi2} for a given amplitude of the bispectrum.

• OSTI ID: 21325327
• Journal Information: Physical Review. D, Particles Fields, Journal Name: Physical Review. D, Particles Fields Journal Issue: 8 Vol. 80; ISSN PRVDAQ; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
AMPLITUDES
COMPUTERIZED SIMULATION
DISTURBANCES
ENTROPY
PERTURBATION THEORY
STRING MODELS
STRING THEORY