Causes of irregular energy density in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi>f</mml:mi><mml:mo stretchy="false">(</mml:mo><mml:mi>R</mml:mi><mml:mo>,</mml:mo><mml:mi>T</mml:mi><mml:mo stretchy="false">)</mml:mo></mml:mrow></mml:math>gravity

Yousaf, Z.; Bamba, Kazuharu; Bhatti, M. Z.

doi:10.1103/physrevd.93.124048

Cited by 200 publications

(51 citation statements)

References 94 publications

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“…Sahoo et al [35] have investigated the background cosmology of power law and exponential law of volumetric expansion in ( , ) gravity in Kaluza-Klein model. Recently Yousaf et al have investigated the irregularity energy density factor in ( , ) theory responsible to disturb the stability of homogeneous universe [36] and also explored the evolutionary behaviour of compact objects [37].…”

Section: Advances In High Energy Physicsmentioning

confidence: 99%

Dynamics of an Anisotropic Universe inf(R,T)Theory

Mishra

Tarai

Tripathy

2016

Advances in High Energy Physics

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Dynamics of an anisotropic universe is studied in ( , ) gravity using a rescaled functional ( , ), where is the Ricci Scalar and is the trace of energy-momentum tensor. Three models have been constructed assuming a power law expansion of the universe. Physical features of the models are discussed. The model parameters are constrained from a dimensional analysis. It is found from the work that the anisotropic Bianchi type VI ℎ (BVI ℎ ) model in the modified gravity generally favours a quintessence phase when the parameter ℎ is either −1 or 0. We may not get viable models in conformity with the present day observation for ℎ = 1.

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Section: Advances In High Energy Physicsmentioning

confidence: 99%

Dynamics of an Anisotropic Universe inf(R,T)Theory

Mishra

Tarai

Tripathy

2016

Advances in High Energy Physics

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“…Recently, a kind of modified theory of gravity has been developed, f (R, T ) gravity, which was first introduced in [122]. This new proposal for modifying gravity has been widely studied within various contexts such as thermodynamics [123][124][125][126], energy conditions [127][128][129], cosmological solutions from dynamical system point of view [130,131], anisotropic cosmology [132][133][134], wormhole solution [135], scalar perturbations [136], cosmology of non-interacting Chaplygin gas [137,138], and some other studies such as f (R, T ) gravity in higher dimensions [139][140][141][142], the effects of matter-curvature coupling on the distribution of matter configuration for a self-gravitating spherical body [143] and dark matter effects in spiral galaxies [144]. This theory extends f (R) gravity by including the trace of the energymomentum tensor (EMT), in addition to the Ricci curvature scalar.…”

Section: Introductionmentioning

confidence: 99%

Stability of the Einstein static universe in f(R, T) gravity

Shabani¹,

Ziaie²

2017

Eur. Phys. J. C

131

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The Einstein static (ES) universe has played a major role in various emergent scenarios recently proposed in order to cure the problem of the initial singularity of the standard model of cosmology. In the model we address, we study the existence and stability of an ES universe in the context of f (R, T ) modified theories of gravity. Considering specific forms of the f (R, T ) function, we seek for the existence of solutions representing ES state. Using dynamical system techniques along with numerical analysis, we find two classes of solutions: the first one is always unstable of the saddle type, while the second is always stable so that its dynamical behavior corresponds to a center equilibrium point. The importance of the second class of solutions is due to the significant role they play in constructing non-singular emergent models in which the universe could have experienced past-eternally a series of infinite oscillations about such an initial static state after which it enters, through a suitable physical mechanism, to an inflationary era. Considering specific forms for the functionality of f (R, T ), we show that this theory is capable of providing cosmological solutions which admit emergent universe (EU) scenarios. We also investigate homogeneous scalar perturbations for the mentioned models. The stability regions of the solutions are parametrized by a linear equation of state (EoS) parameter and other free parameters that will be introduced for the models. Our results suggest that modifications in f (R, T ) gravity would lead to stable solutions which are unstable in f (R) gravity model.

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“…ey [33] analyzed the role of electric charge on the entire analytical solutions which are stable, nonevent horizon and singularity free in nature. Also, Yousaf and his collaborators [34][35][36][37][38] have worked on the stability of gravastars in several modified theories of gravity.…”

Section: Introductionmentioning

confidence: 99%

Isotropic Gravastar Model in Rastall Gravity

Abbas

Majeed

2020

Advances in Astronomy

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In the present paper, we have introduced a new model of gravastar with an isotropic matter distribution in Rastall gravity by the Mazur–Mottola (2004) mechanism. Mazur–Mottola approach is about the construction of gravastar which is predicted as an alternative to black hole. By following this convention, we define gravastar in the form of three phases. The first one is an interior phase which has negative density; the second part consists of thin shell comprising ultrarelativistic stiff fluid for which we have discussed the length, energy, and entropy. By the graphical analysis of entropy, we have shown that our proposed thin shell gravastar model is potentially stable. The third phase of gravastar is defined by the exterior Schwarzschild geometry. For the interior of gravastar, we have found the analytical solutions free from any singularity and the event horizon in the framework of Rastall gravity.

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Causes of irregular energy density inf(R,T)gravity

Cited by 200 publications

References 94 publications

Dynamics of an Anisotropic Universe inf(R,T)Theory

Dynamics of an Anisotropic Universe inf(R,T)Theory

Stability of the Einstein static universe in f(R, T) gravity

Isotropic Gravastar Model in Rastall Gravity

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