Anisotropic non-Gaussianity from a two-form field

Junko Ohashi*, Jiro Soda, Shinji Tsujikawa

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

62 Citations (Scopus)


We study an inflationary scenario with a two-form field to which an inflaton couples nontrivially. First, we show that anisotropic inflation can be realized as an attractor solution and that the two-form hair remains during inflation. A statistical anisotropy can be developed because of a cumulative anisotropic interaction induced by the background two-form field. The power spectrum of curvature perturbations has a prolate-type anisotropy, in contrast to the vector models having an oblate-type anisotropy. We also evaluate the bispectrum and trispectrum of curvature perturbations by employing the in-in formalism based on the interacting Hamiltonians. We find that the nonlinear estimators fNL and τNL are correlated with the amplitude g* of the statistical anisotropy in the power spectrum. Unlike the vector models, both fNL and τNL vanish in the squeezed limit. However, the estimator fNL can reach the order of 10 in the equilateral and enfolded limits. These results are consistent with the latest bounds on fNL constrained by Planck.

Original languageEnglish
Article number083520
JournalPhysical Review D - Particles, Fields, Gravitation and Cosmology
Issue number8
Publication statusPublished - 2013 Apr 22
Externally publishedYes

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Physics and Astronomy (miscellaneous)


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