## 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, φ_{1} and φ_{2}, with exponential potentials, -V_{t} exp(-c _{t}φ_{i}, 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 f_{NL} = 5c_{j}
^{2}/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 | AIP Conference Proceedings |

Pages | 121-125 |

Number of pages | 5 |

Volume | 1040 |

DOIs | |

Publication status | Published - 2008 |

Externally published | Yes |

Event | KEK Cosmophysics Group Inaugural Conference - Accelerators in the Universe, AIU 2008 - Tsukuba Duration: 2008 Mar 12 → 2008 Mar 14 |

### Other

Other | KEK Cosmophysics Group Inaugural Conference - Accelerators in the Universe, AIU 2008 |
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City | Tsukuba |

Period | 08/3/12 → 08/3/14 |

## Keywords

- Cosmological perturbation theory
- String theory and cosmology

## ASJC Scopus subject areas

- General Physics and Astronomy