Stability of self-gravitating anisotropic fluids in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="d1e22" altimg="si7.svg"><mml:mrow><mml:mi>f</mml:mi><mml:mrow><mml:mo>(</mml:mo><mml:mi>R</mml:mi><mml:mo>,</mml:mo><mml:mi>T</mml:mi><mml:mo>)</mml:mo></mml:mrow></mml:mrow></mml:math> gravity

Bhatti, M. Z.; Yousaf, Z.; Yousaf, M.

doi:10.1016/j.dark.2020.100501

Cited by 80 publications

(27 citation statements)

References 52 publications

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“…This indicates, the universe exhibits a transition from early deceleration to the current acceleration in this model. The behavior of ρ andp from equations (14) and (15) with respect to redshift z is plotted below.…”

Section: General Solutionmentioning

confidence: 99%

Effective equation of state in modified gravity and observational constraints

Arora

Meng

Pacif

et al. 2020

Class. Quantum Grav.

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In this article, the bulk viscosity is introduced in a modified gravity model. The gravitational action has a general f (R, T) form, where R and T are the curvature scalar and the trace of energy momentum tensor respectively. An effective equation of state (EoS) has been investigated in the cosmological evolution with bulk viscosity. In the present scenario, the Hubble parameter which has a scaling relation with the redshift can be obtained generically. The role of deceleration parameter q and equation of state parameter ω is discussed to explain the late-time accelerating expansion of the universe. The statefinder parameters and Om diagnostic analysis are discussed for our obtained model to distinguish from other dark energy models together with the analysis of energy conditions and velocity of sound for the model. We have also numerically investigated the model by detailed maximum likelihood analysis of 580 Type Ia supernovae from Union 2.1 compilation datasets and updated 57 Hubble datasets (31 data points from differential age method and 26 points from BAO and other methods). It is with efforts found that the present model is in good agreement with observations.

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Section: General Solutionmentioning

confidence: 99%

Effective equation of state in modified gravity and observational constraints

Arora

Meng

Pacif

et al. 2020

Class. Quantum Grav.

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“…Their contributions delivered gravitational-radiations, heat-dissipation and flow of super energy associated with magnetic parts of the Weyl-tensor, heat-flux vector and vorticity, respectively. Bhatti and his collaborators [51] considered axial-symmetric configuration to analyze the stability of compact bodies by imposing perturbation scheme in the direction of f (R, T ) gravity. For this purpose they investigated Newtonian as well post-Newtonian realm for particular f (R, T ) model.…”

Section: Introductionmentioning

confidence: 99%

Quasi Static Evolution of Compact Objects in Modified Gravity

Yousaf,

Bamba,

Bhatti

et al. 2022

Preprint

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In this paper, the quasi static-approximation on the hydrodynamics of compact objects is proposed in f (R, T ) gravity, where R is the scalar curvature and T is the trace of stress-energy tensor, by exploring the axial and reflection symmetric space time stuffed with anisotropic and dissipative matter contents. The set of invariant-velocities is defined to comprehend the concept of quasi static-approximation. As a consequence, the evolution of compact objects is shown by analyzing the corresponding modified field, dynamical and scalar equations in this approximation to evoke all the feasible outcomes. Furthermore, the significance of kinematical quantities, modified heat-fluxes and scalar variables are found through the proposed approximation.

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“…In this work we shall work with f (R, T) gravity theory in which the Ricci scalar R is replaced with a suitable functional form of R and trace of energy momentum tensor T [43] and therefore is a straightforward conjecture to f (R) gravity (see [44,45]). f (R, T) gravity have proved to be successful in numerous cosmological sectors such as dark matter [46] dark energy [47], massive pulsars [48,49], super-Chandrasekhar white dwarfs [50], wormholes [51][52][53][54][55][56][57][58][59][60][61], gravitational waves [62][63][64], bouncing cosmology [65,66], baryogenesis [67,68], Big-Bang nucleosynthesis [69] and in varying speed of light scenarios [70]. The article is methodized as follows: In Section II we provide a summary of f (R, T) gravity and solve the field equations assuming a bulk viscous fluid.…”

Section: Introductionmentioning

confidence: 99%

Late-time viscous cosmology in f(R, T) gravity

2021

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The article communicates an alternative route to suffice the late-time acceleration considering a bulk viscous fluid with viscosity coefficient ζ = ζ 0 + ζ 1 H + ζ 2 H 2 , where ζ 0 , ζ 1 , ζ 2 are constants in the framework of f (R, T) modified gravity. We presume the f (R, T) functional form to be f = R + 2αT where α is a constant. We then solve the field equations for the Hubble Parameter and study the cosmological dynamics of kinematic variables such as deceleration, jerk, snap and lerk parameters as a function of cosmic time. We observe the deceleration parameter to be highly sensitive to α and undergoes a signature flipping at around t ∼ 10 Gyrs for α = −0.179 which is favored by observations. The EoS parameter for our model assumes values close to −1 at t 0 = 13.7Gyrs which is in remarkable agreement with the latest Planck measurements. Next, we study the evolution of energy conditions and find that our model violate the Strong Energy Condition in order to explain the late-time cosmic acceleration. To understand the nature of dark energy mimicked by the bulk viscous baryonic fluid, we perform some geometrical diagnostics like the {r, s} and {r, q} plane. We found the model to mimic the nature of a Chaplygin gas type dark energy model at early times while a Quintessence type in distant future. Finally, we study the violation of continuity equation for our model and show that in order to explain the cosmic acceleration at the present epoch, energymomentum must violate.

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Stability of self-gravitating anisotropic fluids in f(R,T) gravity

Cited by 80 publications

References 52 publications

Effective equation of state in modified gravity and observational constraints

Effective equation of state in modified gravity and observational constraints

Quasi Static Evolution of Compact Objects in Modified Gravity

Late-time viscous cosmology in f(R, T) gravity

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