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arXiv · 1308.1142

Conformal-Frame (In)dependence of Cosmological Observations in Scalar-Tensor Theory

Takeshi Chiba·Masahide Yamaguchi
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Abstract

We provide the correspondence between the variables in the Jordan frame and those in the Einstein frame in scalar-tensor gravity and consider the frame-(in)dependence of the cosmological observables. In particular, we show that the cosmological observables/relations (redshift, luminosity distance, temperature anisotropies) are frame-independent. We also study the frame-dependence of curvature perturbations and find that the curvature perturbations are conformal invariant if the perturbation is adiabatic and the entropy perturbation between matter and the Brans-Dicke scalar is vanishing. The relation among various definitions of curvature perturbations in the both frames is also discussed, and the condition for the equivalence is clarified.

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Takeshi Chiba, Masahide Yamaguchi. 2013-10-23. Conformal-Frame (In)dependence of Cosmological Observations in Scalar-Tensor Theory. https://doi.org/10.1088/1475-7516%2F2013%2F10%2F040

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