The hybrid cosmology in the scalar-tensor representation of f(G,T) gravity

In this work, the f(G,T) f ( G , T ) theory of gravity is recast in terms of the φ ϕ and ψ ψ fields within the scalar-tensor formulation, where G 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 ( 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 ( 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 ( G , T ) gravity which can be viewed as an extension of the well-established scalar Einstein–Gauss–Bonnet gravity.