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Within the framework of modified gravity model namely Slotheon model, inspired by the theory of extra dimensions, we explore the behaviour of Dark Energy and the perturbations thereof. The Dark Energy and matter perturbations equations are…

General Relativity and Quantum Cosmology · Physics 2020-07-15 Upala Mukhopadhyay , Debasish Majumdar , Debabrata Adak

The standard cosmological model is in the midst of a stress test, thanks to the tension between supernovae-based measurements of the Hubble constant $H_{0}$ and inferences of its values from Cosmic Microwave Background (CMB) anisotropies.…

Cosmology and Nongalactic Astrophysics · Physics 2024-11-05 K. Rezazadeh , A. Ashoorioon , D. Grin

We consider scalar field models of dark energy interacting with dark matter through a coupling proportional to the contraction of the four-derivative of the scalar field with the four-velocity of the dark matter fluid. The coupling is…

General Relativity and Quantum Cosmology · Physics 2018-02-07 Jibitesh Dutta , Wompherdeiki Khyllep , Nicola Tamanini

In this article we address the well-known cosmic coincidence problem in the framework of the f(G) gravity. In order to achieve this, an interaction between dark energy and dark matter is considered. A set-up is designed and a constraint…

General Relativity and Quantum Cosmology · Physics 2015-06-23 Prabir Rudra

The coincidence problem is studied in the effective Yang-Mills condensate dark energy model. As the effective YM Lagrangian is completely determined by quantum field theory, there is no adjustable parameter in this model except the energy…

Astrophysics · Physics 2010-11-11 Wen Zhao , Yang Zhang

We present a Dark Energy (DE) model with a sound derivation as a natural extension of the Standard Model of particle physics with no free parameters and an excellent fit with current cosmological data improving by 21% the $\Lambda$CDM fit…

Cosmology and Nongalactic Astrophysics · Physics 2018-10-24 A. de la Macorra , E. Almaraz

In this paper we consider that dark energy could be described solely by a complex scalar field with a Bose-Einstein condensate-like potential (denoted as CSFDE), that is, with a self-interaction and a mass term. In particular, we analyse a…

General Relativity and Quantum Cosmology · Physics 2021-03-17 Belen Carvente , Víctor Jaramillo , Celia Escamilla-Rivera , Darío Núñez

Dark energy is a fundamental constituent of our universe, its status in the cosmological field equation should be equivalent to that of gravity. Here we construct a dark energy and matter gravity coupling (DEMC) model of cosmology in a way…

General Physics · Physics 2015-01-14 Ti-Pei Li

In this work we examine the possibility that the dark energy (DE) density, $\rho_{de}$ can be dynamical and appear as a power series expansion of the Hubble rate (and its derivatives), i.e.$\rho_{de}(H,\dot{H},...)$. For the present…

General Relativity and Quantum Cosmology · Physics 2019-07-30 Mehdi Rezaei , Mohammad Malekjani , Joan Sola

We here investigate the model of interacting dark energy in the context of five dimensional brane cosmology. The effective equations of state of dark energy are evaluated for various choices of the variable time dependent cosmological…

General Relativity and Quantum Cosmology · Physics 2016-11-15 Mubasher Jamil

We study a cosmological model in which phantom dark energy is coupled to dark matter by phenomenologically introducing a coupled term to the equations of motion of dark energy and dark matter. This term is parameterized by a dimensionless…

High Energy Physics - Theory · Physics 2009-11-10 Rong-Gen Cai , Anzhong Wang

We investigate the cosmological dynamics of a universe described by Lyra's geometry in the presence of dark energy (DE) and dark matter (DM). Dark energy is modeled as a quintessence scalar field with bulk viscosity, while dark matter is…

Cosmology and Nongalactic Astrophysics · Physics 2025-11-20 Giridhari Deogharia , Madhurima Pandey , Ashadul Halder

In the last decades, a cosmological model that fits observations through a vast range of scales emerged. It goes under the name of ${\Lambda}$CDM. However, there are still challenging questions that remain unanswered by this model, such as…

Cosmology and Nongalactic Astrophysics · Physics 2017-09-25 Michele Mancarella

In this paper we investigate possible solutions to the coincidence problem in flat phantom dark energy models with a constant dark energy equation of state and quintessence models with a linear scalar field potential. These models are…

Cosmology and Nongalactic Astrophysics · Physics 2011-05-19 A. Barreira , P. P. Avelino

A cosmological constant fits all current dark energy data, but requires two extreme fine tunings, both of which are currently explained by anthropic arguments. Here we discuss anti-anthropic solutions to one of these problems: the cosmic…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 Joseph M. Fedrow , Kim Griest

A simple discussion on the backreaction of inhomogeneities in cosmology, focusing on the possibility that it could explain the present acceleration and solve the coincidence problem.

Astrophysics · Physics 2007-05-23 Syksy Rasanen

On the cosmological length scale, recent measurements by WMAP have validated $\Lambda$CDM to a precision not see before in cosmology. Such is not the case on galactic length scales, however, where the `cuspy-core' problem has demonstrated…

Astrophysics · Physics 2007-12-05 A. D. Speliotopoulos

In this talk we present a model of the universe in which dark energy is modelled explicitely with both a dynamical quintessence field and a cosmological constant. Our results confirm the possibility of a collapsing universe (for a given…

Astrophysics · Physics 2007-05-23 Rolando Cardenas , Tame Gonzalez , Osmel Martin , Israel Quiros

Investigations on dark energy (DE) are currently inconclusive about its time evolution. Hints of this possibility do however glow now and then in the horizon. Herein we assess the current status of dynamical dark energy (DDE) in the light…

Cosmology and Nongalactic Astrophysics · Physics 2019-05-06 Joan Sola Peracaula , Adria Gomez-Valent , Javier de Cruz Perez

Currently, a large amount of data implies that the matter constituents of the cosmological dark sector might be collisional. An attractive feature of such a possibility is that, it can reconcile dark matter (DM) and dark energy (DE) in…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-25 K. Kleidis , N. K. Spyrou
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