Cosmology in scalar-tensor $f(R,T)$ gravity

Abstract

In this work, we use reconstruction methods to obtain cosmological solutions in the recently developed scalar-tensor representation of $f(R,T)$ gravity. Assuming that matter is described by an isotropic perfect fluid and the spacetime is homogeneous and isotropic, i.e., the Friedmann-Lemaître-Robsertson-Walker (FLRW) universe, the energy density, the pressure, and the scalar field associated with the arbitrary dependency of the action in $T$ can be written generally as functions of the scale factor. We then select three particular forms of the scale factor: an exponential expansion with $a(t)\propto e^t$ (motivated by the de Sitter solution); and two types of power-law expansion with $a(t)\propto t^{1/2}$ and $a(t)\propto t^{2/3}$ (motivated by the behaviors of radiation- and matter-dominated universes in general relativity, respectively). A complete analysis for different curvature parameters $k=\{-1,0,1\}$ and equation of state parameters $w=\{-1,0,1/3\}$ is provided. Finally, the explicit forms of the functions $f\left(R,T\right)$ associated with the scalar-field potentials of the representation used are deduced.

14 pages, 18 figures

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Cited by in corpus (27)

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• Gravitationally induced particle production in scalar-tensor $f(R,T)$ gravity
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• Dynamical reconstruction of the $\Lambda$CDM model in scalar-tensor $f(R,T)$ gravity
• Moment of inertia and compactness of quark stars within the context of $f(R,T,L_m)$ gravity
• Junction conditions of Palatini $f\left(\mathcal{R},T\right)$ gravity
• Warm Inflation in $f(R,T)$ gravity
• Dark Energy Nature in Logarithmic $f(R,T)$ Cosmology
• Inflation in f(R,T) gravity with Double-Well potential
• Dynamical reconstruction of the $\Lambda$CDM model in the scalar-tensor representation of $f\left(Q,T\right)$ gravity
• Irreversible Geometrothermodynamics of Open Systems in Modified Gravity
• Cosmological effects on $f(\bar{R},\bar{T})$ gravity through a non-standard theory
• Collapsing scenarios of K-essence generalized Vaidya spacetime under $f(\bar{R},\bar{T})$ gravity
• Multi-kink braneworld configurations in the scalar-tensor representation of $f(R,T)$ gravity
• Growth of cosmic perturbations in the modified $f(R,T)$ gravity
• NEC violation in $f(\bar{R},\bar{T})$ gravity in the context of a non-canonical theory via modified Raychaudhuri equation
• Addressing the DESI DR2 Phantom-Crossing Anomaly and Enhanced $H_0$ Tension with Reconstructed Scalar-Tensor Gravity
• Modified $f(R,T)$ theory in light of gravitational wave standard sirens
• Scalar-tensor representation to $f(R,T)-$brane with Gauss-Bonnet gravity
• Scalar-tensor baryogenesis: a scalar-tensor completion of gravitational baryogenesis
• Cosmological implications and causality in $f(R,L_m,T)$ gravity theory with observational constraints
• Cosmological sudden singularities in $f(R,T)$ gravity