The hybrid cosmology in the scalar-tensor representation of gravity

Adam Z. Kaczmarek; Dominik Szczȩśniak

doi:10.1140/epjc/s10052-024-12668-y

2024 Impact factor 4.8

Particles and Fields

Open Access

Eur. Phys. J. C (2024) 84: 375
https://doi.org/10.1140/epjc/s10052-024-12668-y

Regular Article - Theoretical Physics

The hybrid cosmology in the scalar-tensor representation of $f (G, T)$ $f({\mathcal {G}},T)$ gravity

Adam Z. Kaczmarek^a and Dominik Szczȩśniak

Department of Theoretical Physics, Faculty of Science and Technology, Jan Długosz University in Czȩstochowa, 13/15 Armii Krajowej Ave., 42200, Czestochowa, Poland

^a adam.kaczmarek@doktorant.ujd.edu.pl

Received: 20 December 2023
Accepted: 10 March 2024
Published online: 9 April 2024

Abstract

In this work, the $f (G, T)$ $f({\mathcal {G}},T)$ theory of gravity is recast in terms of the $ϕ$ $\phi$ and $ψ$ $\psi$ fields within the scalar-tensor formulation, where $G$ ${\mathcal {G}}$ is the Gauss–Bonnet term and T denotes the trace of the energy–momentum tensor. The general aspects of the introduced reformulation are discussed and the reconstruction of the cosmological scenarios is presented, focusing on the so-called hybrid evolution. As a result, the scalar-tensor $f (G, T)$ $f({\mathcal {G}},T)$ theory is successfully reconstructed for the early and late time approximations with the corresponding potentials. The procedure of recovering the $f (G, T)$ $f({\mathcal {G}},T)$ theory in the original formulation is performed for the late time evolution and a specific quadratic potential. The scalar-tensor formulation introduced herein not only facilitates the description of various cosmic phases but also serves as a viable alternative portrayal of the $f (G, T)$ $f({\mathcal {G}},T)$ gravity which can be viewed as an extension of the well-established scalar Einstein–Gauss–Bonnet gravity.

© The Author(s) 2024

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