论文标题
Palatini $ f（R）$宇宙学的有效国家方程式
The effective Equation of State in Palatini $f(R)$ cosmology
论文作者
论文摘要
我们研究了如何使用状态的宇宙学方程来审查扩展的重力理论，尤其是palatini $ f（r）重力。具体而言，该方法最初是在研究给定模型产生的有效状态方程时组成的。然后，鉴于确定哪些模型与给定有效状态方程兼容，也可以考虑逆问题。我们考虑并解决了一些情况，并表明，例如，幂律模型是（唯一的模型），能够将状态的正压方程转换为有效的正压。此外，如预期的那样，保留了$ f（r）= r $的状态方程式（仅）。从这个角度来看，修改的状态方程是一个能够从一般相对性方面区分重力的特征。我们还研究了二次和非均匀的状态有效方程，特别是它们包含Starobinsky模型和其他模型。
We investigate how the cosmological Equation of State can be used for scrutinizing extended theories of gravity, in particular, the Palatini $f(R)$ gravity. Specifically, the approach consists, at first, in investigating the effective Equation of State produced by a given model. Then, the inverse problem can also be considered in view of determining which models are compatible with a given effective Equation of State. We consider and solve some cases and show that, for example, power-law models are (the only models) capable of transforming barotropic Equations of State into effective barotropic ones. Moreover, the form of Equation of State is preserved (only) for $f(R)=R$, as expected. In this perspective, modified Equations of State are a feature capable of distinguishing Extended Gravity with respect to General Relativity. We also investigate quadratic and non-homogeneous effective Equations of State showing, in particular, that they contain the Starobinsky model and other ones.
