Abstract A bouncing universe is a viable candidate to solve the initial singularity problem. Here we consider bouncing solutions in the context of f ( R , G ) gravity by using an order reduction technique which allows one to find solutions that are perturbatively close to General Relativity. This procedure also acts as a model selection approach. Indeed, several covariant gravitational actions leading to a bounce are directly selected by demanding that the Friedmann equation derived within such gravity theories coincides with the one emerging from Loop Quantum Cosmology.

中文翻译：

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通过降阶在 f(R,G) 引力中弹跳宇宙学

摘要 弹跳宇宙是解决初始奇点问题的可行候选者。在这里，我们通过使用阶数减少技术来考虑在 f ( R , G ) 引力的背景下的弹跳解，该技术允许人们找到与广义相对论微扰接近的解。此过程还充当模型选择方法。实际上，通过要求在此类引力理论中导出的弗里德曼方程与圈量子宇宙学中出现的方程一致，可以直接选择导致反弹的几种协变引力作用。