المؤلفون: Bhatti, M. Z.¹ (AUTHOR) mzaeem.math@pu.edu.pk, Turki, Nasser Bin² (AUTHOR) nassert@ksu.edu.sa, Hanif, S.¹ (AUTHOR) soniahanif9@gmail.com, Malik, A.³ (AUTHOR) adnan.maalik@skt.umt.edu.pk

المصدر: International Journal of Geometric Methods in Modern Physics. Aug2024, Vol. 21 Issue 9, p1-25. 25p.

مصطلحات موضوعية: *ENERGY density, *ELECTRIC charge, *ELECTROMAGNETIC fields, *TENSOR fields, *FLUIDS, *GRAVITY

مصطلحات جغرافية: GREECE

مستخلص: In this paper, we analyze energy density inhomogeneities for charged fluid configuration in the background of f (T) theory and recognize its prime features as computed in GR. The dynamical equations are composed employing Bianchi identities for the standard, f (T) extra terms, and energy-momentum tensor for the electromagnetic field. We evaluate various mathematical models of dissipative and anisotropic fluid distributions in-plane symmetry under f (T) gravity. To proceed with the investigation, we design the f (T) field equations, kinematical quantities, and mass function. We analyzed dynamical variables and Ellis equations in terms of our considered theory. To examine the associated inhomogeneity factors, specific scenarios are illustrated alongside and without dissipation. Within a non-radiating situation, we analyze dust and isotropic and anisotropic matter in the state of electric charge. We examine the inhomogeneity factor of a dissipative fluid via a charged dust haze. We derive that the electromagnetic field fosters matter inhomogeneity, but additional curvature factors make the entire structure more homogenous as time passes. [ABSTRACT FROM AUTHOR]

المؤلفون: Ajmal, M.¹ (AUTHOR) ranaajmal.math@gmail.com, Bhatti, M. Z.¹ (AUTHOR) mzaeem.math@pu.edu.pk

المصدر: International Journal of Geometric Methods in Modern Physics. Dec2023, Vol. 20 Issue 14, p1-19. 19p.

مصطلحات موضوعية: *ELECTRIC charge, *SPEED of sound, *ELECTROMAGNETIC fields, *GRAVITY, *COMPACT objects (Astronomy), *EQUATIONS of state

مستخلص: This work deals with the investigation of several physical elements that contribute to the construction of stellar objects in the f (R , G) theory, where R and G symbolize the Ricci and Gauss–Bonnet scalars, respectively. In the presence of an anisotropic source, we offer the fundamental formalization of this modified theory. To establish the physical viability of our models, we employ various methods. Energy conditions (ECs) will be derived to ensure the physical validity of our models within the context of f (R , G) gravity. Moreover, we examine the physical viability through the assessment of radial and tangential sound speeds. Additionally, we analyze the equation of state (EoS) parameter and the anisotropic factor in the presence of the electromagnetic field's influence. Dense stars are shown to be stable under anisotropy measures and exhibit their physical behavior under anisotropic stresses. We identify regions where the systems occupy high compactness and maintain stable ECs with a particular electric charge contribution. [ABSTRACT FROM AUTHOR]

المؤلفون: Yousaf, Z., Nashed, G. G. L., Bhatti, M. Z., Asad, H.

المصدر: Universe (2218-1997); Jun2022, Vol. 8 Issue 6, pN.PAG-N.PAG, 20p

مصطلحات موضوعية: TRANSPORT equation, ELECTROMAGNETIC fields, FLUIDS, HEAT flux, ENERGY density

مستخلص: This manuscript is devoted to analyze hyperbolically symmetric non-static fluid distribution incorporated with heat flux and electromagnetic field. We have developed a general framework in order to examine the dynamic regime of the matter configuration which eventually results in the static spacetime. With the aim of doing this, we constructed the Einstein-Maxwell (EM) field equations and obtained the conservation equation. Furthermore, the formulation of mass function indicates the presence of the negative energy density, which leads towards the significant quantum implications. Taking into account the transport equation, we have observed the thermodynamical attributes of the fluid. Additionally, quasi- homologous constraint has been utilized to construct several models. We have deduced the worthwhile applications of the astrophysical objects by evaluating several analytical solutions in terms of the kinematical variables. [ABSTRACT FROM AUTHOR]

: Copyright of Universe (2218-1997) is the property of MDPI and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

المؤلفون: Yousaf, Z.¹ (AUTHOR) zeeshan.math@pu.edu.pk, Bhatti, M. Z.¹ (AUTHOR) mzaeem.math@pu.edu.pk, Asad, H.¹ (AUTHOR) hamnaasad2596@gmail.com

المصدر: International Journal of Geometric Methods in Modern Physics. May2022, Vol. 19 Issue 5, p1-22. 22p.

مصطلحات موضوعية: *FLUID pressure, *ELECTROMAGNETISM, *ELECTROMAGNETIC fields, *SPACETIME

مستخلص: The purpose of this paper is to investigate the non-singular solutions of gravitationally vacuumed condensate star in the realm of the f(R, T, Q) theory, where Q = RσηTση. The three-layered gravastar structure has been constructed in the cylindrical spacetime under the effects of electromagnetism in the modified theory. Furthermore, we have studied the effects of electromagnetism on the effective matter, which involves the perfect fluid and isotropic pressure in it. To gain this objective, we consider the cylindrical spacetime and evaluate the three regions mathematically. The metric coefficients are calculated independently for each region. To match the region I and II at a hypersurface, the junction conditions have been calculated. To figure out the dependency of the thickness of shell on different physical features of gravastar, we interpret it graphically as well as mathematically. Subsequently, the noticeable facts are accomplished. [ABSTRACT FROM AUTHOR]

المؤلفون: Bhatti, M. Z.¹ (AUTHOR) mzaeem.math@pu.edu.pk, Yousaf, Z.¹ (AUTHOR), Hanif, S.¹ (AUTHOR)

المصدر: European Physical Journal C -- Particles & Fields. Apr2022, Vol. 82 Issue 4, p1-15. 15p.

مصطلحات موضوعية: *GRAVITATIONAL fields, *ELECTRIC charge, *ELECTROMAGNETIC fields, *TORSION

مستخلص: The present study aims to see how gravitational modification, specifically, the f(T) gravitational field, where T is torsion scalar, impacts static fluid content with hyperbolic symmetry and electromagnetic field. We enlarge Herrera's strategy (Herrera et al. in Phys Rev D 103:024037, 2021) to analyze the impact of electromagnetic field on f(T) gravity. We distinguish the stress–energy tensor by considering the ingredients of the tetrad field in the Minkowski co-ordinate frame, commencing with modified field equations. With the advent of negative density, this sort of fluid is supposed to surpass extreme physical conditions, enabling quantum impacts to be detected. We calculate a viable formulation of mass utilizing the Tolman mass from the viewpoint of f(T) gravity along with the electromagnetic field. The gravitational interference is repulsive, as made evident by the negative value of the Tolman mass. Also, we explored the structure scalars in f(T) gravity and found significant solutions in presence of electric charge. [ABSTRACT FROM AUTHOR]

المؤلفون: Yousaf, Z, Khlopov, Maxim Yu, Bhatti, M Z, Asad, H

المصدر: Monthly Notices of the Royal Astronomical Society; Mar2022, Vol. 510 Issue 3, p4100-4109, 10p

مصطلحات موضوعية: ELECTROMAGNETISM, GENERATING functions, ELECTROMAGNETIC fields, FLUIDS, INDUCTIVE effect

مستخلص: In this work, the study on static fluid distributions under the influence of electromagnetism has been carried out with an emphasis on the hyperbolically symmetric metric. For this purpose, modified gravitational formulations in the presence of charge are used to calculate the effective energy–momentum tensor, which is then further refined by taking into account tetrad field components in the Minkowski coordinate system. Also, we compute the Tolman mass and a suitable formulation of the mass function. It exhibits that the hyperbolically symmetrical source has a negative effective matter density in all stellar formulations. This demonstrates that the quantum processes together with certain excessive constraints are deemed important to explain any physical implementations under the effects of the electromagnetic field. Additionally, we assessed the structure scalars and implemented the orthogonal splitting of the structure scalars and Riemann tensor in this modified gravity. Subsequently, various explicit precise cosmological solutions and their generating functions are developed. [ABSTRACT FROM AUTHOR]

: Copyright of Monthly Notices of the Royal Astronomical Society is the property of Oxford University Press / USA and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

المؤلفون: Bhatti, M. Z.¹ (AUTHOR) mzaeem.math@pu.edu.pk, Yousaf, Z.¹ (AUTHOR) zeeshan.math@pu.edu.pk, Rehman, A.¹ (AUTHOR) attiqwatto786@gmail.com

المصدر: International Journal of Modern Physics D: Gravitation, Astrophysics & Cosmology. Jan2022, Vol. 31 Issue 1, p1-16. 16p.

مصطلحات موضوعية: *GRAVITY, *EQUATIONS of state, *FLUID pressure, *ELECTROMAGNETIC fields, *COMPUTATIONAL electromagnetics

مستخلص: This paper is dedicated to inspecting the appearance of electromagnetic field, which is caused by the presence of charge in the highly compact object named gravastar in the background of f (R , G) theory. According to conjecture introduced by Mazur and Mottola gravastar must be consisted of three sectors. We have interpreted these sectors by using specific equations of states. Spherically static metric, perfect fluid and the isotropic pressure have been used in order to calculate a singularity free solution. Gravitational mass present in the inner sector of gravastar is changed into electromagnetic mass in the existence of charge. The electromagnetic mass model of inner sector is responsible for stability by providing balance to the repulsive pressure, which is caused by the presence of charge. It is observed that the presence of electrical charge has a significant effect on energy content, entropy and proper length of the shell that is demonstrated with the help of graphs. [ABSTRACT FROM AUTHOR]

المؤلفون: Bhatti, M Z¹ (AUTHOR) mzaeem.math@pu.edu.pk, Khlopov, Maxim Yu^2,3,4 (AUTHOR), Yousaf, Z¹ (AUTHOR) zeeshan.math@pu.edu.pk, Khan, S¹ (AUTHOR)

المصدر: Monthly Notices of the Royal Astronomical Society. Sep2021, Vol. 506 Issue 3, p4543-4560. 18p.

مصطلحات موضوعية: *ELECTROMAGNETIC fields, *GRAVITY, *FLUIDS, *STELLAR evolution, *CELESTIAL mechanics, *ANALYTICAL solutions, *CHARGE transfer

مستخلص: The principal idea behind this manuscript is to inspect the complexity of dissipating as well as non-dissipating self-gravitating sources which are coupled with locally anisotropic charged matter. The gravitational equations in the regime of |$f(\mathbb {G})$| (⁠|$\mathbb {G}$| is the Gauss–Bonnet invariant) theory have elaborated for the imperfectly charged stellar configuration to scrutinize the charged object in the presence of |$f(\mathbb {G})$| corrections. The impact of charge distribution on the connection between density inhomogeneity, Weyl tensor, and pressure anisotropy is investigated. By incorporating the constraints of Q H (i.e. the quasi-homologous) evolution and C F = 0, (where C F denotes the complexity factor) multiple analytical solutions to the |$f(\mathbb {G})$| equations of gravity are developed defining the imperfectly charged compact spherical matter. Some of these stellar models (exact solutions) portray a spherical collapsing configuration of a charged fluid in which there arise a cavity about the fluid centre, while other models exhibit a fluid configuration wherein the sphere is totally filled by the fluid. These interior solutions to |$f(\mathbb {G})$| gravitational equations may exhibit some appealing astrophysical phenomenons. [ABSTRACT FROM AUTHOR]

المؤلفون: Bhatti, M. Z.¹ (AUTHOR) mzaeem.math@pu.edu.pk, Yousaf, Z.¹ (AUTHOR), Hussain, F.¹ (AUTHOR)

المصدر: European Physical Journal C -- Particles & Fields. Sep2021, Vol. 81 Issue 9, p1-16. 16p.

مصطلحات موضوعية: *ELECTRIC charge, *SPACETIME, *GRAVITY, *EVOLUTION equations, *ELECTROMAGNETIC fields

مستخلص: The objective of this article is to investigate the effects of electromagnetic field on the generalization of Lemaître–Tolman–Bondi (LTB) spacetime by keeping in view the Palatini f(R) gravity and dissipative dust fluid. For performing this analysis, we followed the strategy deployed by Herrera et al. (Phys Rev D 82(2):024021, 2010). We have explored the modified field equations along with kinematical quantities and mass function and constructed the evolution equations to study the dynamics of inhomogeneous universe along with Raychauduary and Ellis equations. We have developed the relation for Palatini f(R) scalar functions by splitting the Riemann curvature tensor orthogonally and associated them with metric coefficients using modified field equations. We have formulated these scalar functions for LTB and its generalized version, i.e., GLTB under the influence of charge. The properties of GLTB spacetime are consistent with those of the LTB geometry and the scalar functions found in both cases are comparable in the presence of charge and Palatini f(R) curvature terms. The symmetric properties of generalized LTB spacetime are also studied using streaming out and diffusion approximations. [ABSTRACT FROM AUTHOR]

المؤلفون: Bhatti, M. Z.¹ (AUTHOR) mzaeem.math@pu.edu.pk, Yousaf, Z.¹ (AUTHOR) zeeshan.math@pu.edu.pk, Zarnoor¹ (AUTHOR) zarnoormalik25@gmail.com

المصدر: Modern Physics Letters A. 10/10/2019, Vol. 34 Issue 31, pN.PAG-N.PAG. 14p.

مصطلحات موضوعية: *NEUTRON stars, *HYDROSTATIC equilibrium, *GRAVITY, *ELECTROMAGNETIC fields, *FRIEDMANN equations, *REDUCED gravity environments

مستخلص: In this work, we discuss the stability of charged neutron star in the background of f (R ̂) gravity and construct the generalized Tolman–Oppenheimer–Volkoff (TOV) equations. For this, we consider static spherically symmetric geometry to construct the hydrostatic equilibrium equation and deduce TOV equations from modified field equations with electromagnetic effects. We conclude that the generalized TOV equation depicts the stable stars configuration independent of the generic function of the modified gravity if the condition of uniform entropy and chemical composition is assumed. [ABSTRACT FROM AUTHOR]