Conformal-Frame (In)dependence of Cosmological Observations in Scalar-Tensor Theory
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.
Keywords
Cite
@article{arxiv.1308.1142,
title = {Conformal-Frame (In)dependence of Cosmological Observations in Scalar-Tensor Theory},
author = {Takeshi Chiba and Masahide Yamaguchi},
journal= {arXiv preprint arXiv:1308.1142},
year = {2015}
}
Comments
18 pages, v2: minor changes. published version