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In this paper we study the perturbations of a cosmic multi-fluid medium consisting of radiation, dust and a Chaplygin gas. To do so, we follow the 1 + 3 covariant formalism and derive the evolution equations of the fluctuations in the…

General Relativity and Quantum Cosmology · Physics 2020-10-27 Shambel Sahlu , Heba Sami , Anna-Mia Swart , Thato Tsabone , Maye Elmardi , Amare Abebe

Interacting dark energy models may play a crucial role in explaining several important observational issues in modern cosmology and also may provide a solution to current cosmological tensions. Since the phenomenology of the dark sector…

Cosmology and Nongalactic Astrophysics · Physics 2023-12-06 Weiqiang Yang , Supriya Pan , Olga Mena , Eleonora Di Valentino

In this paper, we attempt to explore the possibility of a obtaining a viable emergent universe scenario supported by a type of fluid known as the extended Chaplygin gas, which extends a modification to the equation of state of the well…

General Relativity and Quantum Cosmology · Physics 2025-08-13 Rikpratik Sengupta , Anirban Chanda , B C Paul , M Kalam

Even though the Dark Energy Spectroscopic Instrument (DESI) mission does not exclude a dynamical dark energy evolution, the concordance paradigm, i.e., the $\Lambda$CDM model, remains statistically favored, as it depends on the fewest…

Cosmology and Nongalactic Astrophysics · Physics 2024-11-08 Anna Chiara Alfano , Orlando Luongo , Marco Muccino

The fact that the energy densities of dark energy and matter are similar currently, known as the coincidence problem, is one of the main unsolved problems of cosmology. We present here a model in which a spatial curvature of the universe…

Astrophysics · Physics 2009-11-13 Urbano Franca

In this paper the coupling between dark energy and the other components of the cosmological fluid has been studied. Firstly, it will be shown that the application of general cosmological equations, deduced by the authors in a previous work,…

Cosmology and Nongalactic Astrophysics · Physics 2010-06-02 Alberto C. Balfagon , Raul Ramirez-Satorras , Angel R. Martinez

We perform a detailed analysis of a theoretically motivated dark energy quintessence model which interacts with the dark matter sector of the universe. Utilising the current observational datasets from the Cosmic Microwave Background,…

General Relativity and Quantum Cosmology · Physics 2025-09-12 Atul Ashutosh Samanta , Abhijith Ajith , Sukanta Panda

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

We do a detailed analysis of a well-theoretically motivated interacting dark energy scalar field model with a time-varying interaction term. Using current cosmological datasets from CMB, BAO, Type Ia Supernova, $H(z)$ measurements from…

Cosmology and Nongalactic Astrophysics · Physics 2024-06-11 Trupti Patil , Ruchika , Sukanta Panda

We propose a scenario in which the dark components of the Universe are manifestations of a single bulk viscous fluid. Using dynamical system methods, a qualitative study of the homogeneous, isotropic background scenario is performed in…

Astrophysics · Physics 2008-12-18 R. Colistete , J. C. Fabris , J. Tossa , W. Zimdahl

A late accelerated expansion of the Universe is obtained from non-relativistic particles with a short-range attractive interaction, and low enough temperature to produce a Bose-Einstein condensate; by considering coupled dark-energy…

Cosmology and Nongalactic Astrophysics · Physics 2016-05-13 Jaime Besprosvany , German Izquierdo

Models with dark energy decaying into dark matter have been proposed in Cosmology to solve the coincidence problem. We study the effect of such coupling on the cosmic microwave background temperature anisotropies. The interaction changes…

Astrophysics · Physics 2008-11-26 German Olivares , Fernando Atrio-Brandela , Diego Pavon

We investigate the dynamical behaviour of a general class of interacting models in the dark sector in which the phenomenological coupling between cold dark matter and dark energy is a power law of the cosmic scale factor. From numerical…

Cosmology and Nongalactic Astrophysics · Physics 2017-09-04 F. E. M. Costa , A. O. Ribeiro , F. Roig

In this work, we establish a correspondence between the interacting holographic, new agegraphic dark energy and generalized Chaplygin gas model in Bianchi type I universe. In continue, we reconstruct the potential of the scalar field which…

General Relativity and Quantum Cosmology · Physics 2017-04-26 Vahid Fayaz , Hossien Hossienkhani

The recent observational evidences for the present accelerated stage of the Universe have stimulated renewed interest for alternative cosmologies. In general, such models contain an unknown negative-pressure dark component that explains the…

Astrophysics · Physics 2009-11-07 J. V. Cunha , J. S. Alcaniz , J. A. S. Lima

The coincidence problem of late cosmic acceleration gets significantly alleviated when a suitable interaction between matter and dark energy, either of phantom type or not, enters the picture. We show that a class of models featuring this…

Astrophysics · Physics 2007-05-23 German Olivares , Diego Pavon , Fernando Atrio-Barandela

Interactions between dark matter and dark energy with a given equation of state are known to modify the cosmic dynamics. On the other hand, the strength of these interactions is subject to strong observational constraints. Here we discuss a…

Astrophysics · Physics 2015-05-13 Winfried Zimdahl

Three-form field can give rise to viable cosmological scenarios of dark energy with potentially observable signatures distinct from standard single scalar field models. In this study, the background dynamics of three-form cosmology are…

High Energy Physics - Phenomenology · Physics 2011-11-24 T. Ngampitipan , P. Wongjun

Cosmological analysis based on currently available observations are unable to rule out a sizeable coupling between dark energy and dark matter. However, the signature of the coupling is not easy to grasp, since the coupling is degenerate…

Cosmology and Nongalactic Astrophysics · Physics 2011-03-22 Jian-Hua He , Bin Wang , Elcio Abdalla

We consider a cosmological scenario endowed with an interaction between the universe's dark components $-$ dark matter and dark energy. Specifically, we assume the dark matter component to be a pressure-less fluid, while the dark energy…

General Relativity and Quantum Cosmology · Physics 2021-08-03 Andronikos Paliathanasis , Genly Leon , Wompherdeiki Khyllep , Jibitesh Dutta , Supriya Pan
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