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arXiv · 1302.7304

The statistically anisotropic curvature perturbation generated by f(ϕ)^2 F^2

David H. Lyth·Mindaugas Karčiauskas
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Abstract

The inflaton might be coupled to a gauge field through a term f^2(ϕ) F_μνF^μν. If f \propto a^{-2} where a(t) is the scale factor, the perturbation δW of the gauge field generates a potentially observable statistically anisotropic contribution to the primordial curvature perturbation during slow-roll inflation. The spectrum and bispectrum of this contribution have been calculated using the in-in formalism of quantum field theory. We give a simpler and more complete calculation using only the classical perturbations. The results suggest that either the entire curvature perturbation ζ(both the statistically isotropic and anisotropic parts) is generated during slow-roll inflation, or else it is generated afterwards.

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David H. Lyth, Mindaugas Karčiauskas. 2013-05-16. The statistically anisotropic curvature perturbation generated by f(ϕ)^2 F^2. https://doi.org/10.1088/1475-7516%2F2013%2F05%2F011

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