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arXiv · 1707.01948

Emergence of dynamical dark energy from polynomial $f(R)$ theory in Palatini formalism

Marek Szydlowski·Aleksander Stachowski·Andrzej Borowiec
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Abstract

We consider FRW cosmology in $f(R)= R+ γR^2+δR^3$ modified framework. The Palatini approach reduces its dynamics to the simple generalization of Friedmann equation. Thus we study the dynamics in two-dimensional phase space with some details. After reformulation of the model in the Einstein frame, it reduces to the FRW cosmological model with a homogeneous scalar field and vanishing kinetic energy term. This potential determines the running cosmological constant term as a function of the Ricci scalar. As a result we obtain the emergent dark energy parametrization from the covariant theory. We study also singularities of the model and demonstrate that in the Einstein frame some undesirable singularities disappear.

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Marek Szydlowski, Aleksander Stachowski, Andrzej Borowiec. 2017-07-06. Emergence of dynamical dark energy from polynomial $f(R)$ theory in Palatini formalism. https://doi.org/10.1140/epjc%2Fs10052-017-5181-2

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