http://arxiv.org/abs/2305.15326
In the context of $F(\phi)R$ models of gravity, the conformal invariance of the curvature perturbation on the uniform-field slicings has been already demonstrated in several publications. In this work, we study the conformal invariance of the curvature perturbation defined on hypersurfaces that are comoving with an effective fluid. We derive the comoving curvature perturbation in each conformal frame and relate both. It is shown that the conformal invariance of this gauge-invariant curvature perturbation does not always hold, and the analysis on superhorizon and subhorizon scales is performed in the slow-roll regime of inflation. We find that the comoving curvature perturbation is conformally invariant on superhorizon scales but the same cannot be concluded on the subhorizon regime.
J. Díaz and M. Karčiauskas
Thu, 25 May 23
64/64
Comments: 21 pages