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arXiv · 2403.19215

Dynamical reconstruction of the $\Lambda$CDM model in hybrid metric-Palatini gravity

João Luís Rosa
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Abstract

In this work, we apply the formalism of dynamical systems to analyze the viability of the $\Lambda$CDM model in a generalized form of the hybrid metric-Palatini gravity theory written in terms of its dynamically equivalent scalar-tensor representation. Adopting a matter distribution composed of two relativistic fluids described by the equations of state of radiation and pressureless dust, one verifies that the cosmological phase space features the usual curvature-dominated, radiation-dominated, matter-dominated, and exponentially accelerated fixed points, even in the absence of a dark energy component. A numerical integration of the dynamical equations describing the system, subjected to initial conditions consistent with the cosmographic observations from the Planck satellite and weak-field solar system dynamics, shows that cosmological solutions with the same behavior as the $\Lambda$CDM model in General Relativity (GR) are attainable in this theory, with the deviations from GR being exponentially suppressed at early-times and the scalar-field potential effectively playing the role of dark energy at late times.

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João Luís Rosa. 2024-03-28. Dynamical reconstruction of the $\Lambda$CDM model in hybrid metric-Palatini gravity. https://doi.org/10.1140/epjc%2Fs10052-024-13221-7

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