Dynamics of spherical collapse in energy–momentum squared gravity

Sharif, M.; Gul, M. Zeeshan

doi:10.1142/s0217751x21500044

Cited by 38 publications

(13 citation statements)

References 55 publications

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“…[ 34 ] We have also discussed the dynamics of celestial objects and found that collapse rate reduces in EMSG as compared to GR. [ 35 ] The physical features of a gravastar in this framework has been studied in [36].…”

Section: Literature Reviewmentioning

confidence: 99%

Study of Charged Anisotropic Karmarkar Stars in f(R,T2)$f(\mathcal {R},\mathbb {T}^{2})$ Theory

Sharif

Gul

2023

Fortschritte der Physik

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This paper examines the viable attributes of charged compact stars with anisotropic matter configuration in ffalse(scriptR,T2false)$f(\mathcal {R},\mathbb {T}^{2})$ theory. For this purpose, we use the embedding class‐1 technique and consider a specific functional form of this modified theory, i.e, f(R,double-struckT2)=scriptR−γT2$f(\mathcal {R},\mathbb {T} ^{2})=\mathcal {R}-\gamma \mathbb {T}^{2}$ to examine the geometry of compact objects. The values of unknown parameters are found by the smooth matching of interior (static spherical metric) and exterior (Reissner‐Nordstrom metric of energy‐momentum squared gravity) spacetimes. We investigate the impact of effective fluid parameters anisotropy, equation of state parameters and energy bounds in the inner region of the charged stellar objects. The stability of the stellar models in the presence of charge is examined by speed of sound and adiabatic index. We find that embedding class‐1 solution is physically viable and stable for charged anisotropic stellar objects in this modified theory.

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Section: Literature Reviewmentioning

confidence: 99%

Study of Charged Anisotropic Karmarkar Stars in f(R,T2)$f(\mathcal {R},\mathbb {T}^{2})$ Theory

Sharif

Gul

2023

Fortschritte der Physik

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“…In contrast to most higher-order theories of gravity referred to as f (R) theories, where the gravitational Lagrangian is modified as a nonlinear function of the Ricci scalar curvature R, in EMSG, the higher order of the energy-momentum tensor of the matter fields is considered to modify the general relativity (GR). This theory has recently been taken into consideration and examined in several contexts [7][8][9][10][11][12][13][14]. Moreover, applying some observational measurements, its free parameter has been constrained, e.g., see [3,4,9].…”

Section: Introductionmentioning

confidence: 99%

Light bending and gravitational lensing in energy-momentum-squared gravity

Nazari

2022

Preprint

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In the present work, we derive the motion of light in the weak-field limit of energy-momentumsquared gravity (EMSG). To do so, we introduce the post-Newtonian (PN) expansion of this modified theory of gravity. It is shown that in addition to the Newtonian potential, a new EMSG potential affects the trajectory of photons. As a result, in this theory, photons do not behave as predicted by general relativity (GR). To evaluate the EMSG theory by the solar system tests, we study light deflection and Shapiro time delay. Regarding the results obtained in [1, 2], we restrict the free parameter of the theory and show that it lies within the range −4.0 × 10 −27 m s 2 kg −1 < f 0 < 8.7 × 10 −26 m s 2 kg −1 . This interval is in agreement with those derived in [3,4]. This consistency manifests that this theory passes these solar system tests with flying colors. Interestingly, it turns out that the magnitude of the EMSG correction strongly depends on the density of the deflector. So, we investigate the possible effects of EMSG on images of a light source microlensed by a compact dense object such as neutron stars. It is estimated that the EMSG correction to the position of lensed images could be as large as (1 − 0.1) micro-arcseconds which may be detected by future highresolution missions. Moreover, the total magnification and the shape of light curves are obtained in the EMSG theory. It is revealed that except for a small deviation, the overall behavior of the EMSG light curves is similar to that in GR. We also show that as long as the light source and the dense lens are aligned, the EMSG correction is effective, and the combined light of the lensed images is different from the GR case. This issue makes it possible to observe signatures of this theory in the microlensing regime.

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“…Sharif and Gul [34] explored the structure of cosmic objects through the Noether symmetry approach. They also studied the dynamics of cylindrical collapse with dissipative matter in the presence of charge and deduced that the dissipative matter, electromagnetic field and modified terms reduce the collapse rate [35].…”

Section: Introductionmentioning

confidence: 99%

Impact of Charge on the Complexity of Static Sphere in $f(R,\textbf{T}^{2})$ Gravity

Sharif¹,

Anjum²

2022

Preprint

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This paper investigates the complexity of a charged static sphere filled with anisotropic matter in the background of energy-momentum squared gravity. For this purpose, we evaluate the modified field and conservation equations to determine the structure of celestial system. The mass function is calculated through Misner-Sharp as well as Tolman mass definitions. The complexity of a self-gravitating system depends on different factors such as anisotropic pressure, electromagnetic field, energy density inhomogeneity, etc. We formulate the structure scalars by the orthogonal decomposition of the Riemann tensor to develop a complexity factor containing all vital features of the stellar structure. The vanishing complexity condition is achieved by setting the complexity factor equal to zero. Finally, we construct two static solutions by utilizing the energy density of Gokhroo-Mehra solution as well as the polytropic equation of state along with the zero complexity condition. It is found that electromagnetic field decreases the complexity of stellar structure.

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Dynamics of spherical collapse in energy–momentum squared gravity

Cited by 38 publications

References 55 publications

Study of Charged Anisotropic Karmarkar Stars in f(R,T2)$f(\mathcal {R},\mathbb {T}^{2})$ Theory

Study of Charged Anisotropic Karmarkar Stars in f(R,T2)$f(\mathcal {R},\mathbb {T}^{2})$ Theory

Light bending and gravitational lensing in energy-momentum-squared gravity

Impact of Charge on the Complexity of Static Sphere in $f(R,\textbf{T}^{2})$ Gravity

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