The accelerated expansion in F(G,T_μνT^μν) gravity

2023/05/22 by Mihai Marciu, Marciu, Mihai, Dana Maria Ioan +1
Earth and Planetary Sciences · Physics and Astronomy · #Computational Physics (physics.comp-ph) #Cosmology and Gravitation Theories #FOS: Physical sciences #General Relativity and Quantum Cosmology (gr-qc) #Geophysics and Gravity Measurements #High Energy Physics - Theory (hep-th) #Relativity and Gravitational Theory

paper · pdf · doi:10.48550/arxiv.2305.13045

openalex publication_date 2023/05/22 · openalex created_date 2023/05/24 · openalex updated_date 2026/07/28

Abstract

In the present manuscript the basic Einstein--Hilbert cosmological model is extended, by adding a new functional F(G, T_μνT^μν) in the fundamental action, encoding specific geometrical effects due to a nontrivial coupling with the Gauss-Bonnet invariant (G), and the energy--momentum squared term (T_μνT^μν). After obtaining the corresponding gravitational field equations for the specific decomposition where F(G, T_μνT^μν)=f(G)+g(T_μνT^μν), we have explored the physical features of the cosmological model by considering the linear stability theory, an important analytical tool in the cosmological theory which can reveal the dynamical characteristics of the phase space. The analytical exploration of the corresponding phase space structure revealed that the present model can represent a viable dark energy model, with various stationary points where the effective equation of state corresponds to a de--Sitter epoch, possible explaining the early and late time acceleration of the Universe.

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