Abstract
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.
| Original language | English |
|---|---|
| Article number | 083517 |
| Journal | Physical Review D - Particles, Fields, Gravitation and Cosmology |
| Volume | 80 |
| Issue number | 8 |
| DOIs | |
| Publication status | Published - 2009 Oct 15 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Nuclear and High Energy Physics
Cite this
Full quantum trispectrum in multifield DBI inflation. / Mizuno, Shuntaro; Arroja, Frederico; Koyama, Kazuya.
In: Physical Review D - Particles, Fields, Gravitation and Cosmology, Vol. 80, No. 8, 083517, 15.10.2009.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Full quantum trispectrum in multifield DBI inflation
AU - Mizuno, Shuntaro
AU - Arroja, Frederico
AU - Koyama, Kazuya
PY - 2009/10/15
Y1 - 2009/10/15
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=70449657113&partnerID=8YFLogxK
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U2 - 10.1103/PhysRevD.80.083517
DO - 10.1103/PhysRevD.80.083517
M3 - Article
AN - SCOPUS:70449657113
VL - 80
JO - Physical review D: Particles and fields
JF - Physical review D: Particles and fields
SN - 0556-2821
IS - 8
M1 - 083517
ER -