$f(R,T)=f(R)+\lambda T$ gravity models as alternatives to cosmic acceleration

Abstract

This article presents cosmological models that arise in a subclass of $f(R,T)=f(R)+f(T)$ gravity models, with different $f(R)$ functions and fixed $T$-dependence. That is, the gravitational lagrangian is considered as $f(R,T)=f(R)+\lambda T$, with constant $\lambda$. Here $R$ and $T$ represent the Ricci scalar and trace of the stress-energy tensor, respectively. The modified gravitational field equations are obtained through the metric formalism for the Friedmann-Lemaître-Robertson-Walker metric with signature $(+,-,-,-)$. We work with $f(R)=R+\alpha R^2-\frac{{\mu }^4}{R}$, $f(R)=R+k\ln (\gamma R)$ and $f(R)=R+m{e}^{[-nR]}$, with $\alpha ,\mu ,k,\gamma ,m$ and $n$ all free parameters, which lead to three different cosmological models for our Universe. For the choice of $\lambda =0$, this reduces to widely discussed $f(R)$ gravity models. This manuscript clearly describes the effects of adding the trace of the energy-momentum tensor in the $f(R)$ lagrangian. The exact solution of the modified field equations are obtained under the hybrid expansion law. Also we present the Om diagnostic analysis for the discussed models.

arXiv comment11 pages, 20 figures, Accepted version in EPJ C

References in corpus (66)

• Observation of Gravitational Waves from a Binary Black Hole Merger
• GW170817: Observation of Gravitational Waves from a Binary Neutron Star Inspiral
• The Cosmological Constant and Dark Energy
• Nine-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Parameter Results
• First Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Preliminary Maps and Basic Results
• Detection of the Baryon Acoustic Peak in the Large-Scale Correlation Function of SDSS Luminous Red Galaxies
• GW151226: Observation of Gravitational Waves from a 22-Solar-Mass Binary Black Hole Coalescence
• Cosmological Constant - the Weight of the Vacuum
• Introduction to Modified Gravity and Gravitational Alternative for Dark Energy
• f(R,T) gravity
• The Case for a Positive Cosmological Lambda-term
• Quintessence, Cosmic Coincidence, and the Cosmological Constant
• The Cosmological Constant
• GW170104: Observation of a 50-Solar-Mass Binary Black Hole Coalescence at Redshift 0.2
• Dark energy cosmology: the equivalent description via different theoretical models and cosmography tests
• GW170814: A Three-Detector Observation of Gravitational Waves from a Binary Black Hole Coalescence
• The 2dF Galaxy Redshift Survey: Power-spectrum analysis of the final dataset and cosmological implications
• A Model of Holographic Dark Energy
• New Hubble Space Telescope Discoveries of Type Ia Supernovae at z > 1: Narrowing Constraints on the Early Behavior of Dark Energy
• Models of f(R) Cosmic Acceleration that Evade Solar-System Tests
• Measurements of the Cosmological Parameters Omega and Lambda from the First 7 Supernovae at z >= 0.35
• Kinetically Driven Quintessence
• Disappearing cosmological constant in f(R) gravity
• Entropy Bounds and Dark Energy
• Can modified gravity explain accelerated cosmic expansion?
• Two new diagnostics of dark energy
• Conditions for the cosmological viability of f(R) dark energy models
• 1/R gravity and Scalar-Tensor Gravity
• Curvature quintessence matched with observational data
• Are f(R) dark energy models cosmologically viable ?
• Do consistent $F(R)$ models mimic General Relativity plus $\Lambda$?
• Cross-correlation Tomography: Measuring Dark Energy Evolution with Weak Lensing
• Modified gravity with $\ln R$ terms and cosmic acceleration
• Reconstruction of f(R, T) gravity describing matter dominated and accelerated phases
• Future of the universe in modified gravitational theories: Approaching to the finite-time future singularity
• Hubble parameter measurement constraints on the redshift of the deceleration-acceleration transition, dynamical dark energy, and space curvature
• The Cosmological Constant Problem and Quintessence
• Thermodynamics in f(R,T) Theory of Gravity
• Solar System constraints to general f(R) gravity
• The future evolution and finite-time singularities in $F(R)$-gravity unifying the inflation and cosmic acceleration
• Curing singularities in cosmological evolution of F(R) gravity
• Dark matter as a geometric effect in f(R) gravity
• The simplest non-minimal matter-geometry coupling in the $f(R,T)$ cosmology
• Cosmographic bounds on the cosmological deceleration-acceleration transition redshift in $f(\mathcal{R})$ gravity
• Dark Matter From f(R,T) Gravity
• Cosmological solutions from Induced Matter Model applied to 5D f(R,T) gravity and the shrinking of the extra coordinate
• Cosmology with hybrid expansion law: scalar field reconstruction of cosmic history and observational constraints
• Singularity-free cosmological solutions in quadratic gravity
• Expansion History with Decaying Vacuum: A Complete Cosmological Scenario
• A litmus test for Lambda
• Interacting generalized Chaplygin gas model in non-flat universe
• Viability of f(R) Theories with Additional Powers of Curvature
• Stability of the Einstein static Universe in $f(R,T)$ gravity
• Anisotropic cosmological models in $f(R,T)$ gravity with variable deceleration parameter
• $Om$ diagnostic applied to scalar field models and slowing down of cosmic acceleration
• Influence of $f(R)$ Models on the Existence of Anisotropic Self-Gravitating Systems
• Accelerating Universe in Modified Theories of Gravity
• Making Sense Of The New Cosmology
• Magnetized strange quark model with Big Rip singularity in $f(R,T)$ gravity
• Phantom-Like Behavior in $f(R)$-Gravity
• Kaluza-Klein String Cosmological Model in f(R; T) Theory of Gravity
• Observational constraints on non-minimally coupled Galileon model
• Cosmological consequences and statefinder diagnosis of a non-interacting generalized Chaplygin gas in $f(R,T)$ gravity
• Comments on "Solar System constraints to general f(R) gravity"
• Perturbative approach for mass varying neutrinos coupled to the dark sector in the generalized Chaplygin gas scenario
• Two scalar field cosmology from coupled one-field models

Cited by in corpus (15)

• Wormholes in exponential $f(R,T)$ gravity
• Variable Chaplygin gas cosmologies in f(R, T) gravity with particle creation
• Existence of bulk viscous universe in $f(R,T)$ gravity and confrontation with observational data
• Viability of Bianchi type V Universe in $f(R,T)=f_1(R)+f_2(R)f_3(T)$ gravity
• An exponential shape function for wormholes in modified gravity
• The trace of the trace of the energy-momentum tensor-dependent Einstein's field equations
• Revisiting $f(R,T)$ cosmologies
• Accelerating model of flat universe in $f(R,T)$ gravity
• The study of Kantowski-Sachs perfect fluid cosmological model in modified gravity
• Cosmological effects on $f(\bar{R},\bar{T})$ gravity through a non-standard theory
• Growth of cosmic perturbations in the modified $f(R,T)$ gravity
• Modified $f(R,T)$ theory in light of gravitational wave standard sirens
• Dynamics of General Barotropic Stellar Fluid in the Framework of $R+2\alpha T$ Gravity
• Formation of Singularity and Apparent Horizon for Dissipative Collapse in $f(R,T)$ Theory of Gravity
• Reconstruction of Tsallis Holographic Dark Energy via Modified Non-Metric Gravity: An $f(Q,C)$ Approach