### Abstract

We compute the non-Gaussianity of the curvature perturbation generated by ekpyrotic collapse with multiple fields. The transition from the multi-field scaling solution to a single-field dominated regime converts initial isocurvature field perturbations to an almost scale-invariant comoving curvature perturbation. In the specific model of two fields, Ø1 and Ø2, with exponential potentials, -V_{i} exp(ciØi), we calculate the bispectrum of the resulting curvature perturbation. We find that the non-Gaussianity is dominated by non-linear evolution on super-Hubble scales and hence is of the local form. The non-linear parameter of the curvature perturbation is given by fNL = 5c^{2} _{j}=12, where c _{j} is the exponent of the potential for the field which becomes sub-dominant at late times.

Original language | English |
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Title of host publication | Proceedings of the 17th Workshop on General Relativity and Gravitation in Japan, JGRG 2007 |

Pages | 165-168 |

Number of pages | 4 |

Publication status | Published - 2007 |

Externally published | Yes |

Event | 17th Workshop on General Relativity and Gravitation in Japan, JGRG 2007 - Nagoya Duration: 2007 Dec 3 → 2007 Dec 7 |

### Other

Other | 17th Workshop on General Relativity and Gravitation in Japan, JGRG 2007 |
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City | Nagoya |

Period | 07/12/3 → 07/12/7 |

### Fingerprint

### ASJC Scopus subject areas

- Atomic and Molecular Physics, and Optics

### Cite this

*Proceedings of the 17th Workshop on General Relativity and Gravitation in Japan, JGRG 2007*(pp. 165-168)

**Non-Gaussianities from ekpyrotic collapse with multiple fields.** / Mizuno, Shuntaro; Koyama, Kazuya; Vernizzi, Filippo; Wands, David.

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution

*Proceedings of the 17th Workshop on General Relativity and Gravitation in Japan, JGRG 2007.*pp. 165-168, 17th Workshop on General Relativity and Gravitation in Japan, JGRG 2007, Nagoya, 07/12/3.

}

TY - GEN

T1 - Non-Gaussianities from ekpyrotic collapse with multiple fields

AU - Mizuno, Shuntaro

AU - Koyama, Kazuya

AU - Vernizzi, Filippo

AU - Wands, David

PY - 2007

Y1 - 2007

N2 - We compute the non-Gaussianity of the curvature perturbation generated by ekpyrotic collapse with multiple fields. The transition from the multi-field scaling solution to a single-field dominated regime converts initial isocurvature field perturbations to an almost scale-invariant comoving curvature perturbation. In the specific model of two fields, Ø1 and Ø2, with exponential potentials, -Vi exp(ciØi), we calculate the bispectrum of the resulting curvature perturbation. We find that the non-Gaussianity is dominated by non-linear evolution on super-Hubble scales and hence is of the local form. The non-linear parameter of the curvature perturbation is given by fNL = 5c2 j=12, where c j is the exponent of the potential for the field which becomes sub-dominant at late times.

AB - We compute the non-Gaussianity of the curvature perturbation generated by ekpyrotic collapse with multiple fields. The transition from the multi-field scaling solution to a single-field dominated regime converts initial isocurvature field perturbations to an almost scale-invariant comoving curvature perturbation. In the specific model of two fields, Ø1 and Ø2, with exponential potentials, -Vi exp(ciØi), we calculate the bispectrum of the resulting curvature perturbation. We find that the non-Gaussianity is dominated by non-linear evolution on super-Hubble scales and hence is of the local form. The non-linear parameter of the curvature perturbation is given by fNL = 5c2 j=12, where c j is the exponent of the potential for the field which becomes sub-dominant at late times.

UR - http://www.scopus.com/inward/record.url?scp=84887356274&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84887356274&partnerID=8YFLogxK

M3 - Conference contribution

AN - SCOPUS:84887356274

SP - 165

EP - 168

BT - Proceedings of the 17th Workshop on General Relativity and Gravitation in Japan, JGRG 2007

ER -