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We show the existence of an infinite family of finite-time singularities in isotropically expanding universes which obey the weak, strong, and dominant energy conditions. We show what new type of energy condition is needed to exclude them…

General Relativity and Quantum Cosmology · Physics 2009-11-10 John D. Barrow , Christos G. Tsagas

An explicit model of $F(R)$ gravity with realizing a crossing of the phantom divide is reconstructed. In particular, it is shown that the Big Rip singularity may appear in the reconstructed model of $F(R)$ gravity. Such a Big Rip…

High Energy Physics - Theory · Physics 2010-05-27 Kazuharu Bamba , Chao-Qiang Geng , Shin'ichi Nojiri , Sergei D. Odintsov

Understanding the late-time acceleration of the universe and its subtleties is one of the biggest mysteries in cosmology. A lot of different approaches have been put forward to deal with this, ranging from the conventional cosmological…

General Relativity and Quantum Cosmology · Physics 2024-09-30 Oem Trivedi , Maxim Khlopov

We present cosmic solutions corresponding to universes filled with dark and phantom energy, all having a negative cosmological constant. All such solutions contain infinite singularities, successively and equally distributed along time,…

General Relativity and Quantum Cosmology · Physics 2010-11-02 Salvador Robles-Perez , Prado Martin-Moruno , Alberto Rozas-Fernandez , Pedro F. Gonzalez-Diaz

It is shown that phantom scalar models can be mapped into a mathematically equivalent, modified $F(R)$ gravity, which turns out to be complex, in general. Only for even scalar potentials is the ensuing modified gravity real. It is also…

High Energy Physics - Theory · Physics 2008-11-26 F. Briscese , E. Elizalde , S. Nojiri , S. D. Odintsov

The knowledge of the universe future is of fundamental importance for any advanced civilization. We study the future of singular dark universe where thermal effects due to the Hawking radiation on the apparent horizon of the FRW universe…

General Relativity and Quantum Cosmology · Physics 2020-07-27 Shin'ichi Nojiri , Sergei D. Odintsov

In this work we consider a family of cosmological models featuring future singularities. This type of cosmological evolution is typical of dark energy models with an equation of state violating some of the standard energy conditions (e.g.…

General Relativity and Quantum Cosmology · Physics 2016-12-21 Jose Beltran Jimenez , Ruth Lazkoz , Diego Saez-Gomez , Vincenzo Salzano

Recent observational evidence seems to allow the possibility that our universe may currently be under a dark energy effect of a phantom nature. A suitable effective phantom fluid behaviour can emerge in brane cosmology; In particular,…

General Relativity and Quantum Cosmology · Physics 2009-02-23 Mariam Bouhmadi-Lopez , Paulo Vargas Moniz

We investigate the gravitational collapse of a homogeneous dust cloud in the Shtanov Sahni braneworld model, which incorporates an extra timelike dimension. The interior of the collapsing configuration is modeled by a Friedmann Lemaitre…

General Relativity and Quantum Cosmology · Physics 2025-10-27 Rikpratik Sengupta , Chiranjeeb Singha

The generalized Chaplygin gas (GCG) model allows for an unified description of the cosmologically recent accelerated expansion of the Universe and of the evolution of energy density perturbations. This dark energy - dark matter unification…

Astrophysics · Physics 2007-05-23 O. Bertolami

We propose in this paper a new model for describing the unification of dark energy and dark matter. This new model is a further generalization of the generalized Chaplygin gas (GCG) model, thus dubbed new generalized Chaplygin gas (NGCG)…

Astrophysics · Physics 2009-11-10 Xin Zhang , Feng-Quan Wu , Jingfei Zhang

Some relevant aspects of a new form of generalized entropic cosmology, recently introduced by Nojiri, Odintsov and Faraoni, are considered. The setup is a logarithmic equation of state for a viscous dark fluid coupled with dark matter, in…

General Relativity and Quantum Cosmology · Physics 2026-05-05 E. Elizalde , A. V. Yurov , A. V. Timoshkin

Motivated by condensed matter physical systems, in which a finite-time singularity indicates that the topology of the system changes, we critically examine the possibility of the Universe's topology change at a finite-time cosmological…

General Relativity and Quantum Cosmology · Physics 2019-03-27 V. K. Oikonomou

We investigate the unification scenario provided by the generalised Chaplygin gas model (a perfect fluid characterized by an equation of state p = -A/\rho^{\alpha}). Our concerns lie with a possible tension existing between background…

Cosmology and Nongalactic Astrophysics · Physics 2014-07-18 Juliano Pereira Campos , Júlio César Fabris , Rafael Perez , Oliver F. Piattella , Hermano Velten

We present a Friedmann-Robertson-Walker quantum cosmological model in the presence of Chaplygin gas and perfect fluid for early and late time epoches. In this work, we consider perfect fluid as an effective potential and apply Schutz's…

General Relativity and Quantum Cosmology · Physics 2008-11-26 P. Pedram , S. Jalalzadeh

We demonstrate how holonomy corrections in loop quantum cosmology (LQC) prevent the Big Rip singularity by introducing a quadratic modification in terms of the energy density $\rho$ in the Friedmann equation in the…

General Relativity and Quantum Cosmology · Physics 2015-06-12 Kazuharu Bamba , Jaume de Haro , Sergei D. Odintsov

We investigate various dark energy models by taking into account the thermal effects induced from Hawking radiation on the apparent horizon of the Universe, for example near a finite-time future singularity. If the dark energy density…

General Relativity and Quantum Cosmology · Physics 2021-02-17 Artyom V. Astashenok , Sergei D. Odintsov , Vasilis K. Oikonomou

Depending on the choice of its potential, the scalar phantom field $\phi$ (the equation of state parameter $w<-1$) leads to various catastrophic fates of the universe including big rip, little rip and other future singularity. For example,…

General Relativity and Quantum Cosmology · Physics 2015-06-03 Ping Xi , Xiang-hua Zhai , Xin-zhou Li

We study the evolution of Born-Infeld-type phantom in the second Randall-Sundrum brane scenario, and find that there exists attractor solution for the potential with a maximum, which implies a cosmological constant at the late time.…

High Energy Physics - Theory · Physics 2009-11-10 Dao-jun Liu , Xin-zhou Li

We construct a piecewise model that gives a physical viable realization of finite-time future singularity for a spatially flat Friedmann-Robertson-Walker universe within the interacting dark matter--dark energy framework, with the latter…

General Relativity and Quantum Cosmology · Physics 2017-03-14 Mauricio Cataldo , Luis P. Chimento , Martín G. Richarte
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