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The future finite-time singularities emerging in alternative gravity dark energy models are classified and studied in Jordan and Einstein frames. It is shown that such singularity may occur even in flat spacetime for the specific choice of…

High Energy Physics - Theory · Physics 2009-06-30 S. Capozziello , M. De Laurentis , S. Nojiri , S. D. Odintsov

The present study deals with spatially homogeneous and anisotropic locally rotationally symmetric (LRS) Bianchi type I cosmological model with dominance of dark energy. To get the deterministic model of Universe, we assume that the shear…

General Physics · Physics 2012-01-24 Anil Kumar Yadav , Bijan Saha

In this paper, we have investigated some features of anisotropic accelerating Bianchi type-I cosmological model in the presence of two non-interacting fluids, i.e. one usual string and other dark energy fluid towards the gravitational field…

General Physics · Physics 2020-04-20 S. H. Shekh , V. R. Chirde

This paper contains a detailed discussion on new cosmic solutions describing the early and late evolution of a universe that is filled with a kind of dark energy that may or may not satisfy the energy conditions. The main distinctive…

Astrophysics · Physics 2008-11-26 Artyom V. Yurov , Prado Martin Moruno , Pedro F. Gonzalez-Diaz

In this paper, we investigate the viability of cosmological models featuring a type II singularity that occurs during the past evolution of the Universe. We construct a scenario in which the singularity arises and then constrain the model…

General Relativity and Quantum Cosmology · Physics 2023-09-12 Adam Balcerzak , Tomasz Denkiewicz , Mateusz Lisaj

We investigate the appearance of the classical anisotropic universe from the no-boundary quantum state according to the prescription proposed by Hartle, Hawking and Hertog. Our model is homogeneous, anisotropic, closed universes with a…

General Relativity and Quantum Cosmology · Physics 2009-09-02 Kazuya Fujio , Toshifumi Futamase

We investigate some new similarity inhomogeneous solutions of anisotropic dark energy and perfect fluid in Bianchi type-I space-time. Three different equation of state parameters along the spatial directions are introduced to quantify the…

General Relativity and Quantum Cosmology · Physics 2018-04-12 Ahmad T Ali , Anil Kumar Yadav , Abdulah K Alzahrani

The dynamics of solutions of the Einstein-Vlasov system with Bianchi I symmetry is discussed in the case of massive or massless particles. It is shown that in the case of massive particles the solutions are asymptotic to isotropic dust…

General Relativity and Quantum Cosmology · Physics 2011-07-19 Alan D. Rendall

An oscillating universe cycles through a series of expansions and contractions. We propose a model in which ``phantom'' energy with a supernegative pressure ($p < - \rho$) grows rapidly and dominates the late-time expanding phase. The…

Astrophysics · Physics 2008-03-29 Katherine Freese , Matthew G. Brown , William H. Kinney

It is shown that the existence of the cosmic kinematic fast dynamos in Bianchi type IX rotating cosmological models, faces severe difficulties, due to the fact that in these models rotation increases without bounds, which is strictly…

Astrophysics · Physics 2007-07-23 Garcia de Andrade

We examine the dynamical consequences of homogeneous cosmological magnetic fields in the framework of loop quantum cosmology. We show that a big-bounce occurs in a collapsing magnetized Bianchi I universe, thus extending the known cases of…

General Relativity and Quantum Cosmology · Physics 2008-12-11 Roy Maartens , Kevin Vandersloot

An infinite class of exact static anisotropic spheres is developed. All members of the class satisfy (i) regularity (meaning no singularities), and in particular at the origin, (ii) positive but monotone decreasing energy density…

General Relativity and Quantum Cosmology · Physics 2016-06-13 Kayll Lake

In this paper, we attempt to explore the possibility of a obtaining a viable emergent universe scenario supported by a type of fluid known as the extended Chaplygin gas, which extends a modification to the equation of state of the well…

General Relativity and Quantum Cosmology · Physics 2025-08-13 Rikpratik Sengupta , Anirban Chanda , B C Paul , M Kalam

In this work, we investigate the cosmological dynamics of an anisotropic Universe within the framework of $f(R,T)$ gravity by incorporating pressureless dark matter and the dark energy models. The analysis is carried out in a Bianchi type-I…

General Relativity and Quantum Cosmology · Physics 2026-05-13 S. H. Shekh , N. Myrzakulov , Anirudh Pradhan , M. Zeyauddin

We introduce a new type of generating theorems in General Relativity for anisotropic, static, spherically symmetric solutions of the Einstein field equations. The results are used to derive a class of solutions that can serve as new models…

General Relativity and Quantum Cosmology · Physics 2026-04-14 Paulo Luz , Sante Carloni

Einstein field equations for anisotropic spheres are solved and exact interior solutions obtained. This paper extends earlier treatments to include anisotropic models which accommodate a wider variety of physically viable energy densities.…

General Relativity and Quantum Cosmology · Physics 2008-11-26 M. Chaisi , S. D. Maharaj

Anisotropic cloud string cosmological model with Bianchi type I space time is investigated in the context of general relativity. The exact solutions of Einstein field equations are obtained with when the source for energy momentum tensor is…

General Physics · Physics 2019-09-26 Kangujam Priyokumar Singh , Meher Daimary

We consider the gravitational model with additional spatial dimensions and anisotropic pressure which is nonzero only in these dimensions. Cosmological solutions in this model include accelerated expansion of the Universe at late age of its…

General Relativity and Quantum Cosmology · Physics 2014-02-19 O. A. Grigorieva , G. S. Sharov

We consider an anisotropic brane world with Bianchi type I and V geometries where the mechanism of confining the matter on the brane is through the use of a confining potential. The resulting equations on the anisotropic brane are modified…

General Relativity and Quantum Cosmology · Physics 2008-11-26 M. Heydari-Fard , H. R. Sepangi

In the recent literature it has been shown that the $H_0$ tension may be eliminated if an abrupt physics transition changed the Cepheid parameters in the near past of the Universe, nearly $70-150\,$Myrs ago. In this letter we stress the…

General Relativity and Quantum Cosmology · Physics 2022-02-15 S. D. Odintsov , V. K. Oikonomou