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Related papers: Emergent scenario in the Einstein-Cartan theory

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A stability criterion is derived in general relativity for self-similar solutions with a scalar field and those with a stiff fluid, which is a perfect fluid with the equation of state $P=\rho$. A wide class of self-similar solutions turn…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Tomohiro Harada , Hideki Maeda

In this work, we give a general class of solutions of the spinning cosmic string in Einstein's theory of gravity. After treating same problem in Einstein Cartan (EC) theory of gravity, the exact solution satisfying both exterior and…

General Relativity and Quantum Cosmology · Physics 2009-11-11 N. Ozdemir

We address issues on the origin of gravity and the dark energy (or the cosmological constant) from the perspectives of emergent gravity. We discuss how the emergent gravity reveals a noble, radically different picture about the origin of…

High Energy Physics - Theory · Physics 2008-11-26 Hyun Seok Yang

We prove existence and uniqueness of solutions of the semiclassical Einstein equation in flat cosmological spacetimes driven by a quantum massive scalar field with arbitrary coupling to the scalar curvature. In the semiclassical…

Mathematical Physics · Physics 2021-11-24 Paolo Meda , Nicola Pinamonti , Daniel Siemssen

In this article, we study small perturbations of the family of Friedmann-Lema\^itre-Robertson-Walker cosmological background solutions to the Euler-Einstein system with a positive cosmological constant in 1 + 3 dimensions. The background…

Mathematical Physics · Physics 2010-08-31 Igor Rodnianski , Jared Speck

We investigate the emergent universe scenario in the presence of interacting fluids. The non-linear equation of state (EoS) considered in the general theory of relativity for obtaining emergent universe is effectively a cosmological model…

General Relativity and Quantum Cosmology · Physics 2015-05-20 B. C. Paul , A. S. Majumdar

This paper explores stability of the Einstein universe against linear homogeneous perturbations in the background of $f(\mathcal{G},T)$ gravity. We construct static as well as perturbed field equations and investigate stability regions for…

General Relativity and Quantum Cosmology · Physics 2017-07-26 M. Sharif , Ayesha Ikram

The purpose of this work is to investigate spatially homogeneous and flat cosmological solutions of the Einstein equations coupled to a non-variational ``near-minimal'' scalar field. This coupling model represents a minimal departure from…

General Relativity and Quantum Cosmology · Physics 2026-05-05 Joshua Ritchie

We find a class of solutions for a homogeneous and isotropic universe in which the initially expanding universe stops expanding, experiences contraction, and then expands again (the "bounce"), in the framework of Einstein gravity with a…

General Relativity and Quantum Cosmology · Physics 2019-06-26 Hiroki Matsui , Fuminobu Takahashi , Takahiro Terada

Possibilities emerging out of the dynamical evolutions of collapsing systems are addressed in this thesis through analytical investigations of the highly non-linear Einstein Field Equations. Studies of exact solutions and their properties,…

General Relativity and Quantum Cosmology · Physics 2017-09-07 Soumya Chakrabarti

We present modified Gauss-Bonnet gravity without matter in four dimensions which accommodates flat emergent universe (EU) obtained in Einstein's general theory of gravity with a non-linear equation of state. The EU model is interesting…

Cosmology and Nongalactic Astrophysics · Physics 2020-08-04 B. C. Paul , S. D. Maharaj , A. Beesham

We show that there is a phenomenologically and theoretically consistent limit of the generic Einstein-Aether theory in which the Einstein-Aether field equations reduce to Einstein field equations with a perfect fluid distribution sourced by…

General Relativity and Quantum Cosmology · Physics 2024-09-20 Metin Gurses , Cetin Senturk , Bayram Tekin

We propose a phenomenological approach to the cosmological constant problem based on generally covariant non-local and acausal modifications of four-dimensional gravity at enormous distances. The effective Newton constant becomes very small…

High Energy Physics - Theory · Physics 2007-05-23 Nima Arkani-Hamed , Savas Dimopoulos , Gia Dvali , Gregory Gabadadze

In this work we study classical bouncing solutions in the context of $f({\sf R},{\sf T})={\sf R}+h({\sf T})$ gravity in a flat {\sf FLRW} background using a perfect fluid as the only matter content. Our investigation is based on introducing…

General Relativity and Quantum Cosmology · Physics 2018-06-05 Hamid Shabani , Amir Hadi Ziaie

The cosmological constant is one of the most pressing problems in modern physics. We address this issue from an emergent gravity standpoint, by using an analogue gravity model. Indeed, the dynamics of the emergent metric in a Bose-Einstein…

General Relativity and Quantum Cosmology · Physics 2012-02-29 Stefano Finazzi , Stefano Liberati , Lorenzo Sindoni

KKLT give a mechanism to generate de Sitter vacua in string theory. And recently, the scenario, {\em landscape}, is suggested to explain the problem of the cosmological constant. In this scenario, the cosmological constant is a de Sitter…

High Energy Physics - Theory · Physics 2009-07-06 C. Y. Sun , D. H. Zhang

Stability of the Einstein static universe versus the linear scalar, vector and tensor perturbations is investigated in the context of deformed Ho\v{r}ava-Lifshitz cosmology inspired by entropic force scenario. A general stability condition…

General Relativity and Quantum Cosmology · Physics 2017-02-14 Y. Heydarzade , M. Khodadi , F. Darabi

In this paper, we sketch the proof of the extension of the stability theorem of the Minkowski space in General Relativity done explicitly in previous work by the present author. We discuss solutions of the Einstein vacuum (EV) equations. We…

General Relativity and Quantum Cosmology · Physics 2009-08-10 Lydia Bieri

This paper invokes a new mechanism for reducing a coupled system of fields (including Einstein's equations without a cosmological constant) to equations that possess solutions exhibiting characteristics of immediate relevance to current…

General Relativity and Quantum Cosmology · Physics 2019-11-05 Robin W. Tucker , Timothy J. Walton , Manuel Arrayás , José L. Trueba

We consider the gravitational collapse of a spherically symmetric homogeneous matter distribution consisting of a Weyssenhoff fluid in the presence of a negative cosmological constant. Our aim is to investigate the effects of torsion and…

General Relativity and Quantum Cosmology · Physics 2017-04-19 Amir Hadi Ziaie , Paulo Vargas Moniz , Arash Ranjbar , Hamid Reza Sepangi