标题： 约旦和爱因斯坦框架下的共动曲率扰动 显示英文标题

标题： Comoving curvature perturbation in Jordan and Einstein frames

摘要： 在$F(\phi)R$模型的引力背景下，均匀场切片上的曲率扰动的共形不变性已经在若干出版物中得到证明。 在这项工作中，我们研究了定义在与有效流体共同运动的超曲面上的曲率扰动$\mathcal{R}$，该流体的能量-动量张量是协变守恒的。 我们在 Jordan 和 Einstein 图形中以扰动的一阶推导了$\mathcal{R}$的表达式，并将两者联系起来。 通常情况下，$\mathcal{R}$不是共形不变的，但在慢滚膨胀的大尺度上它是不变的。 利用我们的结果，我们还重新推导了 Jordan 图形中膨胀观测值的表达式。 显示英文摘要

摘要： In the context of $F(\phi)R$ models of gravity, the conformal invariance of the curvature perturbation on uniform-field slices has been already demonstrated in several publications. In this work we study the curvature perturbation $\mathcal{R}$ defined on hypersurfaces that comove with the effective fluid whose energy-momentum tensor is covariantly conserved. We derive the expressions of $\mathcal{R}$ at first order in perturbations in the Jordan and Einstein frames and relate the two. Generically $\mathcal{R}$ is not conformally invariant, but it is on sufficiently large scales during slow-roll inflation. Using our results we also rederive the expressions for inflation observables in the Jordan frame.