Lorentz boost and non-gaussianity in multi-field dbi-inflation

Shuntaro Mizuno, Frederico Arroja, Kazuya Koyama, Takahiro Tanaka

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

We show that higher-order actions for cosmological perturbations in the multi-field DBI inflation model are obtained by a Lorentz boost from the rest frame of the brane to the frame where the brane is moving. We confirm that this simple method provides the same third- And fourth- order actions at leading order in slow-roll and in the small sound speed limit as those obtained by the usual ADM formalism. As an application, we compute the leading order connected four-point function of the primordial curvature perturbation coming from the intrinsic fourth-order contact interaction in the multi-field DBI-inflation model. At third order, the interaction Hamiltonian arises purely by the boost from the second-order action in the rest frame of the brane. The boost acts on the adiabatic and entropy modes in the same way thus there exists a symmetry between the adiabatic and entropy modes. But at fourth order this symmetry is broken due to the intrinsic fourth-order action in the rest frame and the difference between the Lagrangian and the interaction Hamiltonian. Therefore, contrary to the three-point function, the momentum dependence of the purely adiabatic component and the components including the entropic contributions are different in the four-point function. This suggests that the trispectrum can distinguish the multi-field DBI-inflation model from the single field DBI inflation model.

Original languageEnglish
Title of host publication12th Marcel Grossmann Meeting on Recent Dev. in Theoretical and Experimental General Relativity, Astrophysics and Relativistic Field Theories - Proc. of the MG 2009 Meeting on General Relativity
Pages1231-1233
Number of pages3
Publication statusPublished - 2012
Externally publishedYes
Event12th Marcel Grossmann Meeting on Recent Developments in Theoretical and Experimental General Relativity, Astrophysics and Relativistic Field Theories, MG 2009 - Paris
Duration: 2009 Jul 122009 Jul 18

Other

Other12th Marcel Grossmann Meeting on Recent Developments in Theoretical and Experimental General Relativity, Astrophysics and Relativistic Field Theories, MG 2009
CityParis
Period09/7/1209/7/18

Fingerprint

acceleration (physics)
entropy
perturbation
interactions
electric contacts
broken symmetry
curvature
formalism
momentum
acoustics
symmetry

Keywords

  • Inflation;String theory;Cosmology

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Nuclear and High Energy Physics

Cite this

Mizuno, S., Arroja, F., Koyama, K., & Tanaka, T. (2012). Lorentz boost and non-gaussianity in multi-field dbi-inflation. In 12th Marcel Grossmann Meeting on Recent Dev. in Theoretical and Experimental General Relativity, Astrophysics and Relativistic Field Theories - Proc. of the MG 2009 Meeting on General Relativity (pp. 1231-1233)

Lorentz boost and non-gaussianity in multi-field dbi-inflation. / Mizuno, Shuntaro; Arroja, Frederico; Koyama, Kazuya; Tanaka, Takahiro.

12th Marcel Grossmann Meeting on Recent Dev. in Theoretical and Experimental General Relativity, Astrophysics and Relativistic Field Theories - Proc. of the MG 2009 Meeting on General Relativity. 2012. p. 1231-1233.

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Mizuno, S, Arroja, F, Koyama, K & Tanaka, T 2012, Lorentz boost and non-gaussianity in multi-field dbi-inflation. in 12th Marcel Grossmann Meeting on Recent Dev. in Theoretical and Experimental General Relativity, Astrophysics and Relativistic Field Theories - Proc. of the MG 2009 Meeting on General Relativity. pp. 1231-1233, 12th Marcel Grossmann Meeting on Recent Developments in Theoretical and Experimental General Relativity, Astrophysics and Relativistic Field Theories, MG 2009, Paris, 09/7/12.
Mizuno S, Arroja F, Koyama K, Tanaka T. Lorentz boost and non-gaussianity in multi-field dbi-inflation. In 12th Marcel Grossmann Meeting on Recent Dev. in Theoretical and Experimental General Relativity, Astrophysics and Relativistic Field Theories - Proc. of the MG 2009 Meeting on General Relativity. 2012. p. 1231-1233
Mizuno, Shuntaro ; Arroja, Frederico ; Koyama, Kazuya ; Tanaka, Takahiro. / Lorentz boost and non-gaussianity in multi-field dbi-inflation. 12th Marcel Grossmann Meeting on Recent Dev. in Theoretical and Experimental General Relativity, Astrophysics and Relativistic Field Theories - Proc. of the MG 2009 Meeting on General Relativity. 2012. pp. 1231-1233
@inproceedings{373007c9d147402d809f3ec534ea8074,
title = "Lorentz boost and non-gaussianity in multi-field dbi-inflation",
abstract = "We show that higher-order actions for cosmological perturbations in the multi-field DBI inflation model are obtained by a Lorentz boost from the rest frame of the brane to the frame where the brane is moving. We confirm that this simple method provides the same third- And fourth- order actions at leading order in slow-roll and in the small sound speed limit as those obtained by the usual ADM formalism. As an application, we compute the leading order connected four-point function of the primordial curvature perturbation coming from the intrinsic fourth-order contact interaction in the multi-field DBI-inflation model. At third order, the interaction Hamiltonian arises purely by the boost from the second-order action in the rest frame of the brane. The boost acts on the adiabatic and entropy modes in the same way thus there exists a symmetry between the adiabatic and entropy modes. But at fourth order this symmetry is broken due to the intrinsic fourth-order action in the rest frame and the difference between the Lagrangian and the interaction Hamiltonian. Therefore, contrary to the three-point function, the momentum dependence of the purely adiabatic component and the components including the entropic contributions are different in the four-point function. This suggests that the trispectrum can distinguish the multi-field DBI-inflation model from the single field DBI inflation model.",
keywords = "Inflation;String theory;Cosmology",
author = "Shuntaro Mizuno and Frederico Arroja and Kazuya Koyama and Takahiro Tanaka",
year = "2012",
language = "English",
isbn = "9814374512",
pages = "1231--1233",
booktitle = "12th Marcel Grossmann Meeting on Recent Dev. in Theoretical and Experimental General Relativity, Astrophysics and Relativistic Field Theories - Proc. of the MG 2009 Meeting on General Relativity",

}

TY - GEN

T1 - Lorentz boost and non-gaussianity in multi-field dbi-inflation

AU - Mizuno, Shuntaro

AU - Arroja, Frederico

AU - Koyama, Kazuya

AU - Tanaka, Takahiro

PY - 2012

Y1 - 2012

N2 - We show that higher-order actions for cosmological perturbations in the multi-field DBI inflation model are obtained by a Lorentz boost from the rest frame of the brane to the frame where the brane is moving. We confirm that this simple method provides the same third- And fourth- order actions at leading order in slow-roll and in the small sound speed limit as those obtained by the usual ADM formalism. As an application, we compute the leading order connected four-point function of the primordial curvature perturbation coming from the intrinsic fourth-order contact interaction in the multi-field DBI-inflation model. At third order, the interaction Hamiltonian arises purely by the boost from the second-order action in the rest frame of the brane. The boost acts on the adiabatic and entropy modes in the same way thus there exists a symmetry between the adiabatic and entropy modes. But at fourth order this symmetry is broken due to the intrinsic fourth-order action in the rest frame and the difference between the Lagrangian and the interaction Hamiltonian. Therefore, contrary to the three-point function, the momentum dependence of the purely adiabatic component and the components including the entropic contributions are different in the four-point function. This suggests that the trispectrum can distinguish the multi-field DBI-inflation model from the single field DBI inflation model.

AB - We show that higher-order actions for cosmological perturbations in the multi-field DBI inflation model are obtained by a Lorentz boost from the rest frame of the brane to the frame where the brane is moving. We confirm that this simple method provides the same third- And fourth- order actions at leading order in slow-roll and in the small sound speed limit as those obtained by the usual ADM formalism. As an application, we compute the leading order connected four-point function of the primordial curvature perturbation coming from the intrinsic fourth-order contact interaction in the multi-field DBI-inflation model. At third order, the interaction Hamiltonian arises purely by the boost from the second-order action in the rest frame of the brane. The boost acts on the adiabatic and entropy modes in the same way thus there exists a symmetry between the adiabatic and entropy modes. But at fourth order this symmetry is broken due to the intrinsic fourth-order action in the rest frame and the difference between the Lagrangian and the interaction Hamiltonian. Therefore, contrary to the three-point function, the momentum dependence of the purely adiabatic component and the components including the entropic contributions are different in the four-point function. This suggests that the trispectrum can distinguish the multi-field DBI-inflation model from the single field DBI inflation model.

KW - Inflation;String theory;Cosmology

UR - http://www.scopus.com/inward/record.url?scp=84885597103&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84885597103&partnerID=8YFLogxK

M3 - Conference contribution

AN - SCOPUS:84885597103

SN - 9814374512

SN - 9789814374514

SP - 1231

EP - 1233

BT - 12th Marcel Grossmann Meeting on Recent Dev. in Theoretical and Experimental General Relativity, Astrophysics and Relativistic Field Theories - Proc. of the MG 2009 Meeting on General Relativity

ER -