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Non-Gaussianity in Nonminimally Coupled Scalar Field Theory

Seoktae Koh
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Abstract

We consider the non-Gaussianity of the nonlinear density perturbations in a single-field inflationary model when a scalar field couples nonminimally with gravity. Gravity theories with a nonminimal coupling can be transformed into the Einstein gravity with canonical kinetic terms by using a suitable conformal transformation. We find that a nonlinear generalization of the gauge invariant quantity $ζ_i$ is invariant under the conformal transformation. With the help of this conformal invariant property, we calculate the non-Gaussianity, which is characterized by a nonlinear parameter $f_{NL}$, in nonminimal coupled scalar field theory.

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Seoktae Koh. 2005-12-12. Non-Gaussianity in Nonminimally Coupled Scalar Field Theory. https://arxiv.org/abs/astro-ph/0510030

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