Results 71 to 80 of about 1,515,012 (182)

Charged Anisotropic Compact Stars in f(R, ϕ, X) Gravity: A Class I Embedding Approach With Reissner–NordstrÖm Exterior

Advances in High Energy Physics, Volume 2026, Issue 1, 2026.
This work examines the physical characteristics of charged, anisotropic compact spheres within the framework of f(R, ϕ, X) modified gravity. Starting from a static, spherically symmetric spacetime, we employ an Adler‐type ansatz for the temporal metric component gtt.
Adnan Malik, Fatemah Mofarreh, Ayesha Almas, Wedad Albalawi, Aishah Alshehri, Mohammad Rezwan Habib   +5 more
wiley   +1 more source

Spacetimes admitting the Z-symmetric tensor

, 2022
This paper aims to introduce the spacetimes admitting the Z-symmetric tensor. We investigate the properties of these spacetimes for a perfect fluid and a pressureless perfect flluid (a dust).
Zengin, Füsen Özen, Yavuz Taşci, Ayşe   +1 more
core  

Riemann Solitons on Relativistic Bulk‐Viscous Fluid String Spacetime

International Journal of Mathematics and Mathematical Sciences, Volume 2026, Issue 1, 2026.
In this article, we undertake a comprehensive study of almost Riemann solitons and their gradient counterparts within the framework of relativistic bulk‐viscous fluid string (BVFS) geometries. We begin by analyzing the potential vector field. It is shown that, on BVFS backgrounds, this potential vector must coincide with a torse‐forming field which is ...
Mehdi Jafari, Shahroud Azami, Shikha Binwal   +2 more
wiley   +1 more source

Causality and its violation in $$f(R,\mathcal {L}_m,\phi ,g^{\mu \nu }\nabla _\mu \phi \nabla _\nu \phi )$$ f ( R , L m , ϕ , g μ ν ∇ μ ϕ ∇ ν ϕ ) gravity

European Physical Journal C: Particles and Fields
A modified gravitational model whose action is given by an arbitrary function of the Ricci scalar, the matter Lagrangian density, a scalar field, and its kinetic term is investigated as an extension of the gravitational sector including an additional ...
L. A. S. Evangelista, M. L. R. Silva, J. V. Moretti, A. F. Santos   +3 more
doaj   +1 more source

Geometry of Manifolds and Applications

Mathematics
This editorial presents 24 research articles published in the Special Issue entitled Geometry of Manifolds and Applications of the MDPI Mathematics journal, which covers a wide range of topics from the geometry of (pseudo-)Riemannian manifolds and their ...
Adara M. Blaga
doaj   +1 more source

Novel Theorems on Spacetime Admitting Pseudo‐W2 Curvature Tensor

Journal of Mathematics, Volume 2026, Issue 1, 2026.
This paper investigates spacetime manifolds admitting a pseudo‐W2 curvature tensor. We show that a pseudo‐W2 flat spacetime is an Einstein manifold and therefore has constant curvature. Moreover, when the manifold satisfies the Einstein field equations (EFE), with a cosmological constant, the associated energy–momentum tensor is covariantly constant ...
B. B. Chaturvedi, Prabhawati Bhagat, Mohammad Nazrul Islam Khan, Ljubisa Kocinac   +3 more
wiley   +1 more source

Holographic fluids from 5D dilaton gravity

Journal of High Energy Physics
We study a solvable class of five-dimensional dilaton gravity models that continuously interpolate between anti-de Sitter (AdS5), linear dilaton (LD5) and positively curved spacetimes as a function of a continuous parameter ν.
Sylvain Fichet, Eugenio Megías, Mariano Quirós   +2 more
doaj   +1 more source

Lanczos Potentials in Perfect Fluid Cosmologies

, 2004
We derive the equation linking the Weyl tensor with its Lanczos potential, called the Weyl-Lanczos equation, in 1+3 covariant formalism for perfect fluid Bianchi type I spacetime and find an explicit expression for a Lanczos potential of the Weyl tensor ...
Holgersson, David
core   +2 more sources

Observational constraints on the Kerr and its several single-parameter modified spacetimes using quasi-periodic oscillation data

European Physical Journal C: Particles and Fields
This paper investigates the dynamical effects of particles moving in the Kerr spacetime and its nine single-parameter modified spacetimes, including Bardeen, Ayon-Beato and Garcia (ABG), Hayward, Kerr–Newman (KN), Kerr–Taub–NUT (KTN), Braneworld Kerr (BK)
Shining Yang, Jianbo Lu, Wenmei Li, Mou Xu, Jingyang Xu   +4 more
doaj   +1 more source

Signatures of non-metricity on dynamical analysis of isotropic cosmological models

Nuclear Physics B
The characteristics of compact stars are examined in this study utilizing the Kohler-Chao-Tikekar and Tolman IV spacetime models. This study is framed within the f(Q) gravity, a geometric theory of gravity where spacetime curvature is describe by the non-
Tayyab Naseer, M. Sharif, M. Waqas, Kottakkaran Sooppy Nisar, Mohammed Zakarya   +4 more
doaj   +1 more source