Dynamical reconstruction of the $Λ$CDM model in the scalar-tensor representation of $f\left(Q,T\right)$ gravity

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Main Authors: Kaczmarek, Adam Z., Rosa, João Luís, Szczȩśniak, Dominik
Format: Preprint
Published: 2024
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author Kaczmarek, Adam Z.
Rosa, João Luís
Szczȩśniak, Dominik
author_facet Kaczmarek, Adam Z.
Rosa, João Luís
Szczȩśniak, Dominik
contents Motivated by the growing interest in the nonmetricity-matter couplings, we develop the scalar-tensor formulation of recently introduced $f(Q,T)$ gravity, where $Q$ is the nonmetricity and $T$ is the trace of the energy-momentum tensor. The main properties of the scalar-tensor formalism for the Friedmann-Lema{\^ i}tre-Robertson-Walker (FLRW) Universe are discussed, and we introduce an appropriate set of dynamical variables to analyze the cosmic evolution of the scalar-tensor $f(Q,T)$ cosmology as a dynamical system. By considering two distinct cosmic fluids, namely matter and radiation, we have demonstrated that the cosmological phase space exhibits the typical curvature-dominated, radiation-dominated, matter-dominated, and exponentially accelerated fixed points. Furthermore, under an appropriate set of initial conditions compatible with the current observations from the Planck satellite, our analysis shows that the scalar-tensor $f(Q,T)$ successfully yields models indistinguishable from the $Λ$CDM cosmology and compatible with the weak-field solar system dynamics, without the inclusion of a cosmological constant $Λ$. Thus, the theory introduced herein may be regarded as a suitable candidate to describe the cosmological dynamics of the Universe.
format Preprint
id arxiv_https___arxiv_org_abs_2410_00707
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Dynamical reconstruction of the $Λ$CDM model in the scalar-tensor representation of $f\left(Q,T\right)$ gravity
Kaczmarek, Adam Z.
Rosa, João Luís
Szczȩśniak, Dominik
General Relativity and Quantum Cosmology
Motivated by the growing interest in the nonmetricity-matter couplings, we develop the scalar-tensor formulation of recently introduced $f(Q,T)$ gravity, where $Q$ is the nonmetricity and $T$ is the trace of the energy-momentum tensor. The main properties of the scalar-tensor formalism for the Friedmann-Lema{\^ i}tre-Robertson-Walker (FLRW) Universe are discussed, and we introduce an appropriate set of dynamical variables to analyze the cosmic evolution of the scalar-tensor $f(Q,T)$ cosmology as a dynamical system. By considering two distinct cosmic fluids, namely matter and radiation, we have demonstrated that the cosmological phase space exhibits the typical curvature-dominated, radiation-dominated, matter-dominated, and exponentially accelerated fixed points. Furthermore, under an appropriate set of initial conditions compatible with the current observations from the Planck satellite, our analysis shows that the scalar-tensor $f(Q,T)$ successfully yields models indistinguishable from the $Λ$CDM cosmology and compatible with the weak-field solar system dynamics, without the inclusion of a cosmological constant $Λ$. Thus, the theory introduced herein may be regarded as a suitable candidate to describe the cosmological dynamics of the Universe.
title Dynamical reconstruction of the $Λ$CDM model in the scalar-tensor representation of $f\left(Q,T\right)$ gravity
topic General Relativity and Quantum Cosmology
url https://arxiv.org/abs/2410.00707