We study conformal transformations in the most general parity-preserving models of the New General Relativity type. Then we apply them to analysis of cosmological perturbations in the (simplest) spatially flat cosmologies. Strong coupling issues around Minkowski spacetime are seen for many special cases of these models. At the same time, the behaviour of the most general three-parameter case seems to be very robust, presumably always with only the eight first-class constraints coming from diffeomorphisms. Also the case of the so-called 1-parameter New GR doesn't show any discontinuity between Minkowski and the cosmology, though without showing any deviations from GR which would be observable at this level either.

中文翻译：

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新广义相对论中的共形变换和宇宙扰动

我们研究最一般的新广义相对论类型的宇称保持模型中的共形变换。然后我们将它们应用于（最简单的）空间平坦宇宙学中的宇宙学扰动分析。这些模型的许多特殊情况都存在围绕闵可夫斯基时空的强耦合问题。同时，最一般的三参数情况的行为似乎非常稳健，大概总是只有来自微分同胚的八个一等约束。此外，所谓的 1 参数新广义相对论的情况并没有显示出闵可夫斯基和宇宙学之间的任何不连续性，尽管也没有显示出在这个水平上可以观察到的与广义相对论的任何偏差。