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We consider a holographic cosmological model in which the infrared cutoff is fixed by the Ricci's length and dark matter and dark energy do not evolve separately but interact non-gravitationally with one another. This substantially…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 Iván Durán , Diego Pavón

Associated with the cosmic acceleration are the old and new cosmological constant problems, recently put into the more general context of the dark energy problem. In broad terms, the old problem is related to an unexpected order of…

Astrophysics · Physics 2008-11-26 Mustapha Ishak

This article looks at how inhomogeneous spacetime models may be significant for cosmology. First it looks at how the averaging process may affect large scale dynamics, with backreaction effects leading to effective contributions to the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 George F R Ellis

We show that a suitable interaction between a scalar field and a matter fluid in a spatially homogeneous and isotropic spacetime can drive the transition from a matter dominated era to an accelerated expansion phase and simultaneously solve…

Astrophysics · Physics 2009-11-07 Luis P. Chimento , Alejandro S. Jakubi , Diego Pavon , Winfried Zimdahl

We examine the evolution of a universe comprising two interacting fluids, which interact via a term proportional to the product of their densities. In the case of two matter fluids it is shown that the ratio of the densities tends to a…

General Relativity and Quantum Cosmology · Physics 2011-05-13 Sean Z. W. Lip

The dark energy problem may have a simple solution in the model of cosmology based on the space-time interaction hypothesis. The hypothesis throws light on the nature of time (see Time-Transcendence-Truth, Monograph published in 2006).

General Physics · Physics 2020-02-11 S. C. Tiwari

Motivated by the cosmological constant and the coincidence problems, we consider a cosmological model where the cosmological constant $\Lambda_0$ is replaced by a cosmological term $\Lambda(t)$ which is allowed to vary in time. More…

Cosmology and Nongalactic Astrophysics · Physics 2013-07-24 Vincent Poitras

The dynamics of interacting dark matter-dark energy models is characterized through an interaction rate function quantifying the energy flow between these dark sectors. In most of the interaction functions, the expansion rate Hubble…

Cosmology and Nongalactic Astrophysics · Physics 2021-05-05 Weiqiang Yang , Supriya Pan , Llibert Aresté Saló , Jaume de Haro

In this Letter we demonstrate that any interaction of pressureless dark matter with holographic dark energy, whose infrared cutoff is set by the Hubble scale, implies a constant ratio of the energy densities of both components thus solving…

General Relativity and Quantum Cosmology · Physics 2009-09-29 Diego Pavon , Winfried Zimdahl

We explore an autonomous system analysis of dark energy models with interactions between dark energy and cold dark matter in a general systematic approach to cosmological fluids. We investigate two types of models such as local and…

General Relativity and Quantum Cosmology · Physics 2024-03-14 Parth Shah , Gauranga C. Samanta , Kazuharu Bamba , R. Myrzakulov

Within the standard cosmological model, the presence of Dark Energy (DE) is the only structural difference between the early and late times Universe. While its presence is in full display at late times, it is irrelevant at early times,…

Cosmology and Nongalactic Astrophysics · Physics 2023-09-14 Marco Raveri

Cosmic acceleration is explained quantitatively, as an apparent effect due to gravitational energy differences that arise in the decoupling of bound systems from the global expansion of the universe. "Dark energy" is a misidentification of…

General Relativity and Quantum Cosmology · Physics 2008-11-26 David L. Wiltshire

An interesting approach to the cosmological coincidence problem is to allow dark matter and dark energy interact with each other also nongravitationally. We consider two general Ans\"{a}tze for such an interaction and appraise their ability…

General Relativity and Quantum Cosmology · Physics 2013-10-10 Pedro C. Ferreira , Diego Pavón , Joel C. Carvalho

New systematic classification of cosmological models of the present Universe is introduced. After making the comparison of these models with all existing observational data three viable models remain: the cold dark matter model with the…

Astrophysics · Physics 2007-05-23 A. A. Starobinsky

The standard model of cosmology is investigated using time dependent cosmological constant $\Lambda$ and Newton's gravitational constant $G$. The total energy content is described by the modified Chaplygin gas equation of state. It is found…

General Relativity and Quantum Cosmology · Physics 2009-03-12 Mubasher Jamil , Farook Rahaman , Mehedi Kalam

The coupling between the dark components provides a new approach to mitigate the coincidence problem of cosmological standard model. In this paper, dark energy is treated as a fluid with a constant equation of state, whose coupling with…

Cosmology and Nongalactic Astrophysics · Physics 2014-08-18 Weiqiang Yang , Lixin Xu

Two exotic elements have been introduced into the standard cosmological model: non-baryonic dark matter and dark energy. The success in converting a hypothesis into a solid theory depends strongly on whether we are able to solve the…

Cosmology and Nongalactic Astrophysics · Physics 2020-01-08 Martin Lopez-Corredoira

In this manuscript, we investigate late-time cosmology and the evolution of cosmic structures using an interacting dark fluid model in which dark matter (DM) and dark energy (DE) interact through a diffusive mechanism. To provide a…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-01 Shambel Sahlu , Upala Mukhopadhyay , Remudin R. Mekuria , Amare Abebe

Cosmological models with two interacting fluids, each satisfying the strong energy condition, are studied in the framework of classical General Relativity. If the interactions are phenomenologically described by a power law in the scale…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Nelson Pinto-Neto , Bernardo M. O. Fraga

We study a holographic cosmological model in which the infrared cutoff is set by the Ricci's length and dark matter and dark energy do not evolve on their own but interact non-gravitationally with each other. This greatly alleviates the…

Cosmology and Nongalactic Astrophysics · Physics 2011-02-25 Ivan Duran , Diego Pavon
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