Article
Materials Science, Multidisciplinary
Suhail Khan, Furqan Habib, Hassan Shah, Ali H. Alkhaldi, Akram Ali
Summary: This paper investigates exact solutions of anisotropic gravitating source with the cosmological constant in (n + 2) dimensional spacetime, considering collapse and expansion scenarios. By analyzing the expansion scalar and the mass function, the conditions for trapped surfaces are determined. Plots of pressures, anisotropy parameter, and energy density for both collapse and expansion scenarios are presented.
RESULTS IN PHYSICS
(2021)
Article
Physics, Multidisciplinary
M. Sharif, Amal Majid, M. Shafaqat
Summary: This paper examines the general formalism and applications of isotropic and anisotropic polytropic stars in curvature-matter coupled gravity. Physically viable solutions of the field equations are obtained using two polytropic equations of state. The effects of anisotropic pressure on the stellar structure are studied, and the physical behavior of polytropes is graphically inspected through energy conditions and stability criterion.
Article
Physics, Multidisciplinary
M. Sharif, Tayyab Naseer
Summary: This paper discusses the gravitational collapse of dynamical self-gravitating fluid distribution in f(R,T,Q) gravity, where Q = R phi theta T phi theta. In this regard, a charged anisotropic spherical geometry involving dissipation flux and a standard model with coupling parameters Phi and Psi is assumed. The corresponding dynamical and transport equations are formulated using the Misner-Sharp and Muler-Israel Stewart mechanisms. The interlinked evolution equations are used to study the impact of state variables, heat dissipation, modified corrections, and charge on the collapse rate. The Weyl scalar is expressed in terms of the modified field equations and the necessary and sufficient condition for conformal flatness and homogeneous energy density is obtained. Different cases are discussed to investigate the effects of charge and modified corrections on the spherical matter source.
CHINESE JOURNAL OF PHYSICS
(2023)
Article
Physics, Multidisciplinary
Susmita Sarkar, Nayan Sarkar, Farook Rahaman
Summary: This article presents a new model for spherically symmetric anisotropic compact stars with class 1 solutions in f(R, T) gravity. The solutions satisfy all physical parameters and energy conditions, demonstrating equilibrium and stability. The coupling parameter chi plays a crucial role in the characteristics of the solutions.
CHINESE JOURNAL OF PHYSICS
(2022)
Article
Physics, Multidisciplinary
M. Sharif, T. Naseer
Summary: This paper analyzes static spherically symmetric anisotropic solutions in the presence of an electromagnetic field using the gravitational decoupling approach in f(R, T, R gamma upsilon, T gamma upsilon) gravity. The study finds that both sets of solutions are viable and stable for specific values of parameters.
CHINESE JOURNAL OF PHYSICS
(2021)
Article
Physics, Multidisciplinary
Riaz Ahmed, G. Abbas, Ertan Gudekli
Summary: This study investigates the dissipative gravitational collapse of an anisotropic spherically symmetric radiating star in f(R, T) gravity, while confirming the well-behaved energy conditions and other physical properties in the background of f(R, T) theory. The results of the model are consistent with General Relativity when the parameter lambda is set to zero.
CHINESE JOURNAL OF PHYSICS
(2021)
Article
Physics, Mathematical
Allah Ditta, Tiecheng Xia
Summary: The commitment of this work is to find solutions for compact stellar models using the spherically symmetric static space-time and anisotropic matter distribution in the framework of f(T, T) gravity. The authors used specific metric functions and evaluated their solutions based on the Karmarkar condition. By incorporating observational data, they demonstrate the graphical fit and physical admissibility of their solutions.
INTERNATIONAL JOURNAL OF GEOMETRIC METHODS IN MODERN PHYSICS
(2022)
Article
Astronomy & Astrophysics
G. Mustafa, Xia Tie-Cheng, Mushtaq Ahmad, M. Farasat Shamir
Summary: This article investigates compact anisotropic matter profiles in the context of f (R, T) gravity, utilizing spherical symmetric space-time and Karmarkar's condition. By considering Schwarzschild exterior solution and experimental statistics of three different stars, it concludes that all observed stars are realistic, stable, and free from singularities.
PHYSICS OF THE DARK UNIVERSE
(2021)
Article
Physics, Particles & Fields
S. K. Maurya, Riju Nag
Summary: In this paper, we discuss the role of gravitational decoupling in isotropizing the anisotropic solution of Einstein's field equations. We also analyze its influence on the complexity factor in static self-gravitating systems. Additionally, we propose a simple and effective technique to generate new solutions for self-gravitating objects using the complete geometric deformation approach.
EUROPEAN PHYSICAL JOURNAL C
(2022)
Article
Physics, Multidisciplinary
M. Sharif, T. Naseer
Summary: This paper examines the composition of various spherically symmetric star models coupled with anisotropic configuration in f (R, T, Q) gravity. The physical features of compact objects are discussed using a bag model equation of state, and modified field equations are constructed with unknowns (A, B, C) in terms of the Krori-Barua ansatz. Observational data of several stars are used to calculate the unknowns and the bag constant B-c. The behavior of energy density, pressure, and anisotropy is observed through graphical interpretation. The stability of the considered stars is also checked using two criteria. The structure developed in this gravity is found to be in good agreement with all physical requirements.
PRAMANA-JOURNAL OF PHYSICS
(2022)
Article
Physics, Multidisciplinary
Suparna Biswas, Debabrata Deb, Saibal Ray, B. K. Guha
Summary: This study presents spherically symmetric anisotropic charged strange stars under f(R, T) gravity framework, using a simplified MIT bag model equation of state to describe the Strange Quark Matter distribution inside the stars. By calculating the value of B-g from observed mass and radius values for the strange star candidate LMC X-4, the model shows that the coupling constant chi significantly affects the bag constant value. The model demonstrates consistency with physical conditions and offers a viable study on the nature of charged anisotropic massive stellar systems.
Article
Physics, Particles & Fields
Pawan Joshi, Sukanta Panda
Summary: A Hamiltonian for the nonlocal F(R) theory is constructed in this work, revealing the nature of the ghost degrees of freedom. Finally, conditions that lead to ghost-free theories are found.
EUROPEAN PHYSICAL JOURNAL C
(2022)
Article
Astronomy & Astrophysics
Tayyab Naseer, Muhammad Sharif
Summary: In this paper, the isotropic solution is extended to two different anisotropic solutions through minimal geometric deformation method in f(R,T,R rho eta T rho eta) gravity. The physical acceptability and stability of the obtained solutions are analyzed, and it is concluded that this curvature-matter coupling gravity provides more stable solutions corresponding to a self-gravitating geometry.
Article
Astronomy & Astrophysics
T. Vinutha, Venkata Vasavi Kuncham, Sri Kavya Kolli
Summary: In this paper, an anisotropic axially symmetric perfect fluid cosmological model in f (R, T) gravity is studied. The field equations of the present cosmological model are derived by assuming a particular choice for f (R, T). The exact solutions of the field equations are obtained by using specific conditions for the expansion scalar and the scale factor. Various parameters and conditions are discussed for the obtained model, including the pressure, energy density, SEC, DEC, NEC, and cosmological parameter.
GENERAL RELATIVITY AND GRAVITATION
(2023)
Article
Physics, Particles & Fields
Julio C. Fabris, Ednaldo L. B. Junior, Manuel E. Rodrigues
Summary: This article investigates the implementation of black bounce solutions in f(R) theories. It is found that violation of the energy conditions still occurs in these solutions, albeit less severe than in General Relativity (GR) cases. The authors propose a zero-density model with horizons and present a model with positive energy density, which differs from GR.
EUROPEAN PHYSICAL JOURNAL C
(2023)
