English
Related papers

Related papers: Acausality and Nonunique Evolution in Generalized …

200 papers

The improved dynamics of loop quantum cosmology is extended to include the Bianchi type II model. Because these space-times admit both anisotropies and non-zero spatial curvature, certain technical difficulties arise over and above those…

General Relativity and Quantum Cosmology · Physics 2010-01-07 Abhay Ashtekar , Edward Wilson-Ewing

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

We consider a brane universe in an asymptotically de Sitter background spacetime of arbitrary dimensionality. In particular, the bulk spacetime is described by a ``topological de Sitter'' solution, which has recently been investigated by…

High Energy Physics - Theory · Physics 2009-11-07 A. J. M. Medved

We propose the simplest model of teleparallel dark energy with purely a non-minimal coupling to gravity but no self-potential, a single model possessing various interesting features: simplicity, self-potential-free, the guaranteed late-time…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Je-An Gu , Chung-Chi Lee , Chao-Qiang Geng

My research work can be classified into two parts namely, (i) Cosmological phenomena with varying speed of light and (ii) Gravitational collapse and black holes. We have investigated several cosmological phenomena when velocity of light…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Ujjal Debnath

We generalize prior work on the signatures of bulk signals detected by brane-based observers in a spacetime with a compactified dimension. When such braneworlds move with constant velocities or constant proper accelerations in the extra…

High Energy Physics - Theory · Physics 2026-02-17 Ryan Debolt , David Kagan

We consider Brans Dicke scalar vector tensor gravity to study an inflationary scenario of the accelerating expansion of the universe for which the anisotropy property occurs. We study both primordial inflation and late inflationary period…

General Relativity and Quantum Cosmology · Physics 2022-09-20 Hossein Ghaffarnejad , Hoda Gholipour

The generalized teleparallel gravity has been suggested to explain the present cosmic acceleration of the universe. In this paper, we take spatially homogenous and anisotropic Bianchi type $I$ universe in the framework of $F(T)$ gravity.…

General Physics · Physics 2015-06-03 M. Sharif , Shamaila Rani

In the last century, theoretical and experimental developments have established the General Relativity theory as the most successful theory for describing the gravitational phenomenon. On the other hand, in the last two decades, multiple…

General Relativity and Quantum Cosmology · Physics 2025-02-18 Raja Solanki

The stability of the Bianchi type I anisotropic brane cosmology is analyzed in this paper. We also study the effect of the brane solution by comparing the models on the 3-brane and the models in the conventional Einstein's space. Analysis…

High Energy Physics - Theory · Physics 2007-05-23 Chiang-Mei Chen , W. F. Kao

We investigate the behaviour on approach to the initial singularity in higher-order extensions of general relativity by finding exact cosmological solutions for a wide class of models in which the Lagrangian is allowed to depend nonlinearly…

General Relativity and Quantum Cosmology · Physics 2014-11-21 Jonathan Middleton

Bianchi I cosmological solutions in f(T) gravity are discussed. We start from diagonal metrics and tetrads and show that their dynamical equations are pretty much tractable analytically, with a possible arena for physical applications. Then…

General Relativity and Quantum Cosmology · Physics 2026-02-24 Alexey Golovnev , Mustafa M. Hemida

This thesis investigates modified teleparallel gravity models with a scalar field and teleparallel boundary terms, focusing on their cosmological implications for late-time cosmic acceleration. Teleparallel gravity, is an alternative to…

General Relativity and Quantum Cosmology · Physics 2025-01-22 S. A. Kadam

Motivated by anomalies in cosmic microwave background observations, we investigate the implications of $f(Q, T)$ gravity in Bianchi type-I spacetime, aiming to characterize the universe's spatially homogeneous and anisotropic properties. By…

Cosmology and Nongalactic Astrophysics · Physics 2024-09-30 A. Zhadyranova , M. Koussour , V. Zhumabekova , O. Donmez , S. Muminov , J. Rayimbaev

The detection of a time variation of the angle between two distant sources would reveal an anisotropic expansion of the Universe. We study this effect of "cosmic parallax" within the "ellipsoidal universe" model, namely a particular…

Cosmology and Nongalactic Astrophysics · Physics 2011-06-29 L. Campanelli , P. Cea , G. L. Fogli , L. Tedesco

We consider possible resolutions of singularities in a contracting anisotropic universe for a class of higher derivative gravity theories. We give evidence that for our models the big crunch singularity may be replaced by a nearly flat…

High Energy Physics - Theory · Physics 2008-11-26 Philipp Höffer v. Loewenfeld , Ivo Sachs

Density perturbations in cosmology, i.e. spherically symmetric adiabatic perturbations of a Friedmann-Lema\^itre-Robertson-Walker (FLRW) spacetime, are locally exactly equivalent to a different FLRW solution, as long as their wavelength is…

Cosmology and Nongalactic Astrophysics · Physics 2017-02-21 Hiu Yan Ip , Fabian Schmidt

Considering the Universe as a dynamic system, the understanding of its evolution is an interesting aspect of study in cosmology. Here, we investigate the anisotropic locally rotationally symmetric (LRS) Bianchi type-I (LRS-BI) spacetime…

General Relativity and Quantum Cosmology · Physics 2024-06-21 Pranjal Sarmah , Umananda Dev Goswami

We present here an overview of our basic understanding and recent developments on spacetime singularities in the Einstein theory of gravity. Several issues related to physical significance and implications of singularities are discussed.…

General Relativity and Quantum Cosmology · Physics 2015-06-17 Pankaj S. Joshi

We discuss the cosmological evolution of a braneworld in five dimensional Gauss-Bonnet gravity. Our discussion allows the fifth (bulk) dimension to be space-like as well as time-like. The resulting equations of motion have the form of a…

General Relativity and Quantum Cosmology · Physics 2014-11-18 Hideki Maeda , Varun Sahni , Yuri Shtanov