Dark effects in $$\tilde{f}(R,P)$$ gravity

Marciu, Mihai

doi:10.1140/epjc/s10052-021-09871-6

Cited by 6 publications

(2 citation statements)

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“…In order to solve the dark energy problem, various theoretical ramifications have emerged [22]. In the modified gravity theories, the fundamental Einstein-Hilbert action is extended, by adding specific invariants which can be associated to the origin of the accelerated expansion [23][24][25][26]. One of the first model is the f (R) scenario [27], a theoretical model which is based on the scalar curvature, extending the Einstein-Hilbert action in a more natural approach [28].…”

Section: Introductionmentioning

confidence: 99%

Physical aspects of ${f}(R,G_{μν}T^{μν})$ modified gravity theories

Marciu¹,

Maria²

2023

Preprint

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Section: Introductionmentioning

confidence: 99%

Physical aspects of ${f}(R,G_{μν}T^{μν})$ modified gravity theories

Marciu¹,

Maria²

2023

Preprint

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“…In the modified gravity landscape the Einsteinian cubic gravity [20] represents an interesting and possible viable theory studied in the recent years [21][22][23][24][25][26][27][28][29][30][31]. This theory is based on a specific invariant, constructed using third order contractions of the Riemann tensor [20].…”

Section: Introductionmentioning

confidence: 99%

Tachyonic cosmology with cubic contractions of the Riemann tensor

Marciu

2022

Eur. Phys. J. C

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A new cosmological theory is proposed in the theoretical framework of modified gravity theories which is based on a tachyonic field non-minimally coupled with a specific topological invariant constructed with third order contractions of the Riemann tensor. After proposing the action of the cosmological model, the modified Friedmann relations and the Klein–Gordon equations are obtained, describing the corresponding geometrical corrections to the Einstein–Hilbert action. The physical features of the cosmological system are investigated by adopting the dynamical system analysis in the case of an exponential function for the geometrical coupling term. The investigation revealed that the cosmological system can explain the current accelerated expansion of the Universe and the matter dominated epoch, showing a high compatibility to the recent history of our Universe for various values of the coupling coefficients.

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Physical aspects of modified gravity theories

Marciu

Maria

2023

Chinese Phys. C

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The paper extends basic Einstein--Hilbert action by adding an invariant constructed from a specific contraction between the Einstein tensor and the energy momentum tensor, encoding a non--minimal coupling between the space--time geometry and the matter fields. The fundamental Einstein--Hilbert action is extended by considering a generic function ${f}(R,G_{\mu \nu}T^{\mu \nu})$ which is further decomposed into its main constituents, a geometric component which depends on the scalar curvature, and a second element embedding the interplay between geometry and matter fields. Specific cosmological models are established at the level of background dynamics, based on particular couplings between the matter energy--momentum tensor and the Einstein tensor. After deducing the resulting field equations, the physical aspects for the cosmological model are investigated by employing a dynamical system analysis for various coupling functions. The investigation showed that the present model is compatible with different epochs in the evolution of our Universe, possible explaining various late time historical stages.

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Dark effects in $$\tilde{f}(R,P)$$ gravity

Abstract: In the present paper a new cosmological model is proposed by extending the Einstein–Hilbert Lagrangian with a generic functional $$\tilde{f}(R,P)$$ f ~ ( R , P ) , which depends on the scalar curvature R and a term P which … Show more

Cited by 6 publications

References 64 publications

Physical aspects of ${f}(R,G_{μν}T^{μν})$ modified gravity theories

Physical aspects of ${f}(R,G_{μν}T^{μν})$ modified gravity theories

Tachyonic cosmology with cubic contractions of the Riemann tensor

Physical aspects of modified gravity theories

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