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In this study, we demonstrate a new anisotropic solution to the Einstein field equations in Finch-Skea spacetime. The physical features of stellar configuration are studied in previous investigations. We create a model that meets all…

General Relativity and Quantum Cosmology · Physics 2023-06-28 Ankita Jangid , B. S. Ratanpal , K Venkataratnam Kamma

A recently proposed nonlinear transport equation is used to model bulk viscous cosmologies that may be far from equilibrium, as happens during viscous fluid inflation or during reheating. The asymptotic stability of the de Sitter and…

General Relativity and Quantum Cosmology · Physics 2009-10-30 L Chimento , A Jakubi , V Mendez , R Maartens

We establish the nonlinear stability to the future of tilted two-fluid Bianchi I solutions to the Einstein-Euler equations with positive cosmological constant and linear equations of state…

General Relativity and Quantum Cosmology · Physics 2025-08-22 Grigorios Fournodavlos , Elliot Marshall , Todd A. Oliynyk

We study the stability of the isotropic vacuum Friedmann universe in gravity theories with higher-order curvature terms of the form $(R_{ab}R^{ab})^{n}$ added to the Einstein-Hilbert Lagrangian of general relativity on approach to an…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Jonathan Middleton , John D. Barrow

We present a class of exact solutions for homogeneous, anisotropic cosmologies in four dimensions derived from the low-energy string effective action including a homogeneous dilaton $\phi$ and antisymmetric tensor potential $B_{\mu\nu}$.…

High Energy Physics - Theory · Physics 2011-07-19 E. J. Copeland , Amitabha Lahiri , David Wands

In this paper, we investigate a non-canonical scalar field model in the background dynamics of anisotropic Locally Rotationally Symmetric (LRS) Bianchi type I universe where gravity is coupled minimally to scalar field which is taken as…

General Relativity and Quantum Cosmology · Physics 2023-11-17 Sujoy Bhanja , Goutam Mandal , Abdulla Al Mamon , Sujay Kr. Biswas

Structure formation models with a cosmological constant are successful in explaining large-scale structure data, but are threatened by the magnitude-redshift relation for Type Ia supernovae. This has led to discussion of models where the…

Astrophysics · Physics 2009-12-30 Pedro T P Viana , Andrew R Liddle

Cosmological solution to the gravitational field equations in the generalized Randall-Sundrum model for an anisotropic brane with Bianchi I geometry and perfect fluid as matter sources has been considered. The matter on the brane is…

General Relativity and Quantum Cosmology · Physics 2019-12-16 Rikpratik Sengupta , Prasenjit Paul , Bikash Chandra Paul , Saibal Ray

In this paper, we would like to figure out whether a k-inflation model admits the Bianchi type I metric as its inflationary solution under a constant-roll condition in the presence of the supergravity motivated coupling between scalar and…

General Relativity and Quantum Cosmology · Physics 2023-04-03 Duy H. Nguyen , Tuyen M. Pham , Thien D. Le , Tuan Q. Do

A non-local gravity model, which includes a function $f(\Box^{-1} R)$, where $\Box$ is the d'Alembert operator, is considered. For the model with an exponential $f(\Box^{-1} R)$ de Sitter solutions are explored, without any restrictions on…

General Relativity and Quantum Cosmology · Physics 2019-10-30 E. Elizalde , E. O. Pozdeeva , S. Yu. Vernov

We investigate a non-singular cosmological scenario in which uniform-rate inflation is realised on an anisotropic Shtanov-Sahni braneworld. The model naturally resolves the initial singularity resulting in an infinite number of smooth…

General Relativity and Quantum Cosmology · Physics 2026-02-10 Rikpratik Sengupta , Arkajit Aich , Kaushik Bhattacharya

We study the linear stability of entire radial solutions $u(re^{i\theta})=f(r)e^{i\theta}$, with positive increasing profile $f(r)$, to the anisotropic Ginzburg-Landau equation \[ -\Delta u -\delta (\partial_x+i\partial_y)^2\bar u…

Analysis of PDEs · Mathematics 2021-07-01 Xavier Lamy , Andrés Zúñiga

We consider a warm inflationary scenario in which the two dominant matter components present in the early Universe, the scalar field, and the radiation fluid, evolve with different four-velocities. This cosmological system is mathematically…

General Relativity and Quantum Cosmology · Physics 2021-03-15 Tiberiu Harko , Haidar Sheikhahmadi

Solutions to flat space Friedmann-Robertson-Walker cosmologies in Brans-Dicke theory with a cosmological constant are investigated. The matter is modelled as a $\gamma$-law perfect fluid. The field equations are reduced from fourth order to…

General Relativity and Quantum Cosmology · Physics 2009-10-22 Shawn J. Kolitch

The dynamics and evolution of Bianchi type I space-times is considered in the framework of the four-dimensional truncation of a reduced theory obtained from the N=2,D=5 supergravity. The general solution of the gravitational field equations…

High Energy Physics - Theory · Physics 2009-10-31 Chiang-Mei Chen , T. Harko , M. K. Mak

We investigate exact solutions of the Einstein field equations in higher-dimensional, spatially homogeneous Bianchi type-I spacetimes, introducing a real parameter $\lambda$ that correlates the expansion rates of external and internal…

General Relativity and Quantum Cosmology · Physics 2025-07-02 Nihan Katırcı

We study the cosmological evolution of a type-0 string theory by employing non-criticality, which may be induced by fluctuations of the D3 brane worlds. We check the consistency of the approach to O(alpha ') in the corresponding…

High Energy Physics - Theory · Physics 2009-11-07 G. A. Diamandis , B. C. Georgalas , N. E. Mavromatos , E. Papantonopoulos , I. Pappa

We present a dynamical analysis in terms of new expansion-normalized variables for homogeneous and anisotropic Bianchi-I spacetimes in $f(R)$ gravity in the presence of anisotropic matter. With a suitable choice of the evolution parameter,…

General Relativity and Quantum Cosmology · Physics 2019-03-29 Saikat Chakraborty , Kazuharu Bamba , Alberto Saa

We discuss the stability of the higher-dimensional de Sitter (dS) brane solutions with two-dimensional internal space in the Einstein-Maxwel theory. We show that an instability appears in the scalar-type perturbations with respect to the dS…

High Energy Physics - Theory · Physics 2008-11-26 Masato Minamitsuji

A Bianchi type-I cosmological model in the presence of a magnetic flux along a cosmic string is investigated. A nonlinear spinor field is used to simulate the cosmological cloud of strings. It is shown that the spinor field simulation offer…

General Relativity and Quantum Cosmology · Physics 2015-05-01 Bijan Saha , Mihai Visinescu