Non-Gaussianities from ekpyrotic collapse with multiple fields

Shuntaro Mizuno, Kazuya Koyama, Filippo Vernizzi, David Wands

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

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, -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.

Original languageEnglish
Title of host publicationProceedings of the 17th Workshop on General Relativity and Gravitation in Japan, JGRG 2007
Pages165-168
Number of pages4
Publication statusPublished - 2007
Externally publishedYes
Event17th Workshop on General Relativity and Gravitation in Japan, JGRG 2007 - Nagoya
Duration: 2007 Dec 32007 Dec 7

Other

Other17th Workshop on General Relativity and Gravitation in Japan, JGRG 2007
CityNagoya
Period07/12/307/12/7

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ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

Cite this

Mizuno, S., Koyama, K., Vernizzi, F., & Wands, D. (2007). Non-Gaussianities from ekpyrotic collapse with multiple fields. In Proceedings of the 17th Workshop on General Relativity and Gravitation in Japan, JGRG 2007 (pp. 165-168)