Dynamical reconstruction of the $Λ$CDM model in hybrid metric-Palatini gravity
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arXiv
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| Format: | Preprint |
| Publié: |
2024
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| _version_ | 1866914937191792640 |
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| author | Rosa, João Luís |
| author_facet | Rosa, João Luís |
| contents | In this work, we apply the formalism of dynamical systems to analyze the viability of the $Λ$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 $Λ$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. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2403_19215 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Dynamical reconstruction of the $Λ$CDM model in hybrid metric-Palatini gravity Rosa, João Luís General Relativity and Quantum Cosmology In this work, we apply the formalism of dynamical systems to analyze the viability of the $Λ$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 $Λ$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. |
| title | Dynamical reconstruction of the $Λ$CDM model in hybrid metric-Palatini gravity |
| topic | General Relativity and Quantum Cosmology |
| url | https://arxiv.org/abs/2403.19215 |