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We consider finite-time, future (sudden or Big Rip type) singularities which may occur even when strong energy condition is not violated but equation of state parameter is time-dependent. Recently, example of such singularity has been…

High Energy Physics - Theory · Physics 2008-11-26 Shin'ichi Nojiri , Sergei D. Odintsov

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

The SNe type Ia data admit that the Universe today may be dominated by some exotic matter with negative pressure violating all energy conditions. Such exotic matter is called {\it phantom matter} due to the anomalies connected with…

General Relativity and Quantum Cosmology · Physics 2008-11-26 K. A. Bronnikov , J. C. Fabris , S. V. B. Gonçalves

Anisotropic dark energy model with dynamic pressure anisotropies along different spatial directions is constructed at the backdrop of a spatially homogeneous diagonal Bianchi type $V$ $(BV)$ space-time in the framework of General…

General Physics · Physics 2017-05-10 B. Mishra , S. K. Tripathy

The familiar Bang/Crunch singularities of classical cosmology have recently been augmented by new varieties: rips, sudden singularities, and so on. These tend to be associated with final states. Here we consider an alternative possibility…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Brett McInnes

We investigate a model of gravitational collapse of matter inhomogeneities where the latter are modelled as Bianchi type IX (BIX) spacetimes. We found that this model contains, as limiting cases, both the standard spherical collapse model…

General Relativity and Quantum Cosmology · Physics 2022-03-15 Leonardo Giani , Oliver F. Piattella , Alexander Yu. Kamenshchik

The behavior near the initial singular state of the anisotropy parameter of the arbitrary type, homogeneous and anisotropic Bianchi models is considered in the framework of the brane world cosmological models. The matter content on the…

General Relativity and Quantum Cosmology · Physics 2009-11-10 T. Harko , M. K. Mak

We investigate classically non-singular bounces caused by dark energy. In the presence of positive spatial curvature, vacuum energy, either in the form of a cosmological constant or a scalar field potential, allows for an open set of…

High Energy Physics - Theory · Physics 2019-06-26 Sebastian F. Bramberger , Jean-Luc Lehners

The big bounce singularity of a simple 5D cosmological model is studied. Contrary to the standard big bang space-time singularity, this big bounce singularity is found to be an event horizon at which the scale factor and the mass density of…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Lixin Xu , Hongya Liu , Beili Wang

Bianchi cosmologies are ``natural'' anisotropic extensions of the Friedmann universes and they have long been used to investigate the cosmological implications of anisotropy. The latter introduces new ingredients to the standard scenarios,…

General Relativity and Quantum Cosmology · Physics 2024-09-13 Amalia Tzartinoglou , Christos G. Tsagas

Some features of the Bianchi type-I universes in the presence of a fluid that wields an anisotropic equation of state (EoS) parameter are discussed in the context of general relativity. The models that exhibit de Sitter volumetric expansion…

General Relativity and Quantum Cosmology · Physics 2010-03-02 Ozgur Akarsu , Can B. Kilinc

The general form of the anisotropy parameter of the expansion for Bianchi type-III metric is obtained in the presence of a single diagonal imperfect fluid with a dynamically anisotropic equation of state parameter and a dynamical energy…

General Relativity and Quantum Cosmology · Physics 2014-11-20 Ozgur Akarsu , Can B. Kilinc

In this paper, we present a model of transitioning universe with minimal interaction between perfect fluid and anisotropic dark energy in Bianchi I space-time. The two sources are assumed to minimally interacted and therefore their energy…

General Relativity and Quantum Cosmology · Physics 2016-08-19 Anil Kumar Yadav

In this paper a possibility to accelerated the expansion of the large scale universe due to interacting varying Chaplygin gas of a specific form and a tachyonic matter is considered. A specific form of the potential and appropriate values…

General Physics · Physics 2017-08-16 Martiros Khurshudyan

We construct solutions of the Friedmann equations near a sudden singularity using generalized series expansions for the scale factor, the density, and the pressure of the fluid content. In this way, we are able to arrive at a solution with…

General Relativity and Quantum Cosmology · Physics 2013-01-29 John D. Barrow , S. Cotsakis , A. Tsokaros

We consider new models of dark energy with finite time future singularities, by introducing the pressure density as a function of the scale factor. This approach gives acceptable phenomenological models of dark energy, practically…

General Relativity and Quantum Cosmology · Physics 2019-07-17 L. N. Granda

This work explains how the presence of a Type-IV singularity (a mild singularity) can influence the dynamics of a bouncing universe. In particular, we examine bounce cosmology that appears with a Type-IV singularity in the context of a…

General Relativity and Quantum Cosmology · Physics 2022-05-24 Sergei D. Odintsov , Tanmoy Paul

We present the particular case of the Stephani solution for shear-free perfect fluid with uniform energy density and non-uniform pressure. Such models appeared as possible alternative to the consideration of the exotic forms of matter like…

General Relativity and Quantum Cosmology · Physics 2020-01-22 Elena Kopteva , Irina Bormotova , Maria Churilova , Zdenek Stuchlik

In homogeneous and isotropic loop quantum cosmology, gravity can behave repulsively at Planckian energy densities leading to the replacement of the big bang singularity with a big bounce. Yet in any bouncing scenario it is important to…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Dah-Wei Chiou , Kevin Vandersloot

By studying first a new decelerating sudden future singularity (SFS) universe we report finding a novel type of cosmological singularity which we dub a finite time pseudo-rip (FTPR) because unlike for a pseudo-rip, it happens in the finite…

General Relativity and Quantum Cosmology · Physics 2026-05-21 Mariusz P. Dąbrowski , Teodor Borislavov Vasilev