Primordial statistical anisotropy generated at the end of inflation

Journal Article · Fri Aug 15 04:00:00 EDT 2008 · Journal of Cosmology and Astroparticle Physics

DOI:https://doi.org/10.1088/1475-7516/2008/08/005· OSTI ID:22156698

Yokoyama, Shuichiro ^[1]; Soda, Jiro ^[2]

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1. Department of Physics and Astrophysics, Nagoya University, Aichi 464-8602 (Japan)
2. Department of Physics, Kyoto University, Kyoto 606-8501 (Japan)

We present a new mechanism for generating primordial statistical anisotropy of curvature perturbations. We introduce a vector field which has a non-minimal kinetic term and couples with a waterfall field in a hybrid inflation model. In such a system, the vector field gives fluctuations of the end of inflation and hence induces a subcomponent of curvature perturbations. Since the vector has a preferred direction, the statistical anisotropy could appear in the fluctuations. We present the explicit formula for the statistical anisotropy in the primordial power spectrum and the bispectrum of curvature perturbations. Interestingly, there is the possibility that the statistical anisotropy does not appear in the power spectrum but does appear in the bispectrum. We also find that the statistical anisotropy provides the shape dependence to the bispectrum.

• OSTI ID: 22156698
• Journal Information: Journal of Cosmology and Astroparticle Physics, Journal Name: Journal of Cosmology and Astroparticle Physics Journal Issue: 08 Vol. 2008; ISSN 1475-7516
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ANISOTROPY
DISTURBANCES
INFLATIONARY UNIVERSE
SPECTRA
STATISTICS
VECTOR FIELDS