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Cosmological models with different types of Dark Energy are becoming viable alternatives for standard models with the cosmological constant. Yet, such models are more difficult to analyze and to simulate. We present analytical…

Astrophysics · Physics 2009-11-07 R. Mainini , A. V. Maccio' , S. A. Bonometto , A. Klypin

The dark energy dominated warm dark matter (WDM) model is a promising alternative cosmological scenario. We explore large-scale structure formation in this paradigm. We do this in two different ways: with the halo model approach and with…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 Aurel Schneider , Robert E. Smith , Andrea V. Maccio , Ben Moore

This study explores the impact of cosmic curvature on structure formation through general relativistic first-order perturbation theory. We analyze continuity and Euler equations, incorporating cosmic curvature into Einstein equations.…

Cosmology and Nongalactic Astrophysics · Physics 2025-05-29 Bikash R. Dinda

We discuss the evolution of density perturbations of dark matter and dark energy in cosmological models which admit future singularities in a finite time. Up to now geometrical tests of the evolution of the universe do not differentiate…

Cosmology and Nongalactic Astrophysics · Physics 2015-04-10 Tomasz Denkiewicz

The existence of dark matter and dark energy in cosmology is implied by various observations, however, they are still unclear because they have not been directly detected. In this Letter, an unified model of dark energy and dark matter that…

Cosmology and Nongalactic Astrophysics · Physics 2016-10-27 Jiro Matsumoto

The present work is an example of the application of the dynamical system analysis in the context of cosmology. Here cosmic evolution is considered in the background of homogeneous and isotropic flat Friedmann-Lema\^{i}tre-Robertson-Walker…

General Relativity and Quantum Cosmology · Physics 2020-11-20 Soumya Chakraborty , Sudip Mishra , Subenoy Chakraborty

We study cosmological perturbations in a model of unified dark matter and dark energy with a sharp transition in the late-time universe. The dark sector is described by a dark fluid which evolves from an early stage at redshifts $z > z_C$…

Cosmology and Nongalactic Astrophysics · Physics 2018-09-05 Rodrigo R. Cuzinatto , Léo G. Medeiros , Eduardo M. de Morais , Robert H. Brandenberger

In this review we consider in detail different theoretical topics associated with interaction in the dark sector. We study linear and nonlinear interactions which depend on the dark matter and dark energy densities. We consider a number of…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-25 Yu. L. Bolotin , A. Kostenko , O. A. Lemets , D. A. Yerokhin

We investigate the characteristic modifications in the evolving cosmological perturbations when dark energy interacts with dust-like matter, causing the latter's background energy density fall off with time faster than usual. Focusing in…

Cosmology and Nongalactic Astrophysics · Physics 2022-04-06 Mohit Kumar Sharma , Sourav Sur

The standard cold dark matter (CDM) model predicts too many and too dense small structures. We consider an alternative model that the dark matter undergoes two-body decays with cosmological lifetime $\tau$ into only one type of massive…

Cosmology and Nongalactic Astrophysics · Physics 2015-11-04 Dalong Cheng , M. -C. Chu , Jiayu Tang

We revisit a cosmological model where dark matter (DM) and dark energy (DE) follow barotropic equations of state, allowing deviations from the standard $\Lambda$CDM framework (i.e. $w_{dm} \neq 0$, $w_{de} \neq -1$), considering both flat…

Cosmology and Nongalactic Astrophysics · Physics 2025-11-24 Dorian Araya , Cristian Castillo , Genly Leon , Juan Magaña , Angie Barr Domínguez , Miguel A. García-Aspeitia

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

While there is plentiful evidence in all fronts of experimental cosmology for the existence of a non-vanishing dark energy (DE) density \rho_D in the Universe, we are still far away from having a fundamental understanding of its ultimate…

Astrophysics · Physics 2011-07-19 Javier Grande , Ana Pelinson , Joan Sola

In the context of a homogeneous and isotropic universe, we consider the degeneracy condition at the background level between two scenarios in which processes out of equilibrium are possible; this consideration allows us to deviate from the…

General Relativity and Quantum Cosmology · Physics 2025-03-05 Gilberto Aguilar-Pérez , Ana A. Avilez-López , Miguel Cruz

The matter creation cosmology is revisited, including the evolution of baryons and dark matter particles. The creation process affects only dark matter and not baryons. The dynamics of the $\Lambda$CDM model can be reproduced only if two…

Cosmology and Nongalactic Astrophysics · Physics 2014-07-08 J. C. Fabris , J. A. de Freitas Pacheco , O. F. Piattella

A $\Lambda$CDM model with dark matter that decays into inert relativistic energy on a timescale longer than the Hubble time will produce an expansion history that can be misinterpreted as stable dark matter with time-varying dark energy. We…

Cosmology and Nongalactic Astrophysics · Physics 2010-08-27 Sourish Dutta , Robert J. Scherrer

Cold Dark Matter (CDM) has become the standard modern theory of cosmological structure formation. Its predictions appear to be in good agreement with data on large scales, and it naturally accounts for many properties of galaxies. But…

Astrophysics · Physics 2007-05-23 Joel R. Primack

In the standard cosmological model a mysterious cold dark matter (CDM) component dominates the formation of structures. Numerical studies of the formation of CDM halos have produced several robust results that allow unique tests of the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 Jürg Diemand , Ben Moore

We construct a cosmological model which is physically reasonable, mathematically tractable, and extends the study of CDM models to the case where the equations of state (EoS) for matter and dark energy (DE) vary with time. It is based on…

General Relativity and Quantum Cosmology · Physics 2012-06-14 J. Ponce de Leon

We investigate the creation of cold dark matter (CCDM) cosmology as an alternative to explain the cosmic acceleration. Particular attention is given to the evolution of density perturbations and constraints coming from recent observations.…

Cosmology and Nongalactic Astrophysics · Physics 2014-04-11 Rudnei O. Ramos , Marcelo Vargas dos Santos , Ioav Waga
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