Primordial non-Gaussianities in new ekpyrotic cosmology

Shuntaro Mizuno*, Kazuya Koyama, Filippo Vernizzi, David Wands

*Corresponding author for this work

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

6 Citations (Scopus)


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, φ1 and φ2, with exponential potentials, -Vt exp(-c tφi, 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 = 5cj 2/12, where cj is the exponent of the potential for the field which becomes sub-dominant at late times.

Original languageEnglish
Title of host publicationAIP Conference Proceedings
Number of pages5
Publication statusPublished - 2008
Externally publishedYes
EventKEK Cosmophysics Group Inaugural Conference - Accelerators in the Universe, AIU 2008 - Tsukuba
Duration: 2008 Mar 122008 Mar 14


OtherKEK Cosmophysics Group Inaugural Conference - Accelerators in the Universe, AIU 2008


  • Cosmological perturbation theory
  • String theory and cosmology

ASJC Scopus subject areas

  • General Physics and Astronomy


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