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We explore the bounds that can be placed on interactions between cold dark matter and vacuum energy, with equation of state $w=-1$, using state-of-the-art cosmological observations. We consider linear perturbations about a simple background…

Cosmology and Nongalactic Astrophysics · Physics 2023-02-08 Chakkrit Kaeonikhom , Hooshyar Assadullahi , Jascha Schewtschenko , David Wands

Any unified dark matter cosmology can be decomposed into dark matter interacting with vacuum energy, without introducing any additional degrees of freedom. We present observational constraints on an interacting vacuum plus dark energy…

Cosmology and Nongalactic Astrophysics · Physics 2013-04-16 Yuting Wang , David Wands , Lixin Xu , Josue De-Santiago , Alireza Hojjati

The considerable difference between early and late universe measurements of the Hubble constant, called the Hubble tension, poses a potential challenge to the standard $\Lambda$CDM cosmological model. We examine an interacting dark…

Cosmology and Nongalactic Astrophysics · Physics 2026-05-11 Yismaw Wassie Ambelu , Amare Abebe , Solomon Belay Tessema , Shambel Sahlu

Considering the general Lagrangian of k-essence models, we study and classify them through variables connected to the fluid equation of state parameter w_\kappa. This allows to find solutions around which the scalar field describes a…

Astrophysics · Physics 2008-11-26 Daniele Bertacca , Sabino Matarrese , Massimo Pietroni

We study a coupled quintessence model with pure momentum exchange and present the effects of such an interaction on the Cosmic Microwave Background (CMB) and matter power spectrum. For a wide range of negative values of the coupling…

Cosmology and Nongalactic Astrophysics · Physics 2016-08-24 Alkistis Pourtsidou , Thomas Tram

We examine the growth of structure in three different cosmological models with interacting dark matter and vacuum energy. We consider the case of geodesic dark matter with zero sound speed, where the relativistic growing mode in…

Cosmology and Nongalactic Astrophysics · Physics 2020-05-20 Humberto A Borges , David Wands

We explore the cosmological implications of the interactions among the dark particles in the dark $SU(2)_R$ model. It turns out that the relevant interaction is between dark energy and dark matter, through a decay process. With respect to…

Cosmology and Nongalactic Astrophysics · Physics 2018-07-02 Ricardo G. Landim , Rafael J. F. Marcondes , Fabrízio F. Bernardi , Elcio Abdalla

Almost in all interacting dark energy models present in the literature, the stability of the model becomes potentially sensitive to the dark energy equation of state parameter $w_x$, and a singularity arises at `$w_x = -1$'. Thus, it…

Cosmology and Nongalactic Astrophysics · Physics 2019-01-02 Weiqiang Yang , Ankan Mukherjee , Eleonora Di Valentino , Supriya Pan

We constrain an interacting, holographic dark energy model, first proposed by two of us in [1], with observational data from supernovae, CMB shift, baryon acoustic oscillations, x-rays, and the Hubble rate. The growth function for this…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-21 Iván Durán , Diego Pavón , Winfried Zimdahl

In our present work, we study the evolution of the universe by assuming an interacting dark energy model, where dark energy interacts with matter. Basing on this model, first we calculated the dark energy density parameter and using this we…

General Relativity and Quantum Cosmology · Physics 2019-12-30 Debasis Sahu , Bibekananda Nayak

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

In this paper, we present an analytical solution for the interacting generalized holographic dark energy model, assuming a linear interaction rate between dark energy and dark matter. We determine the equation of state parameter, the…

General Relativity and Quantum Cosmology · Physics 2024-10-15 Omar Enkhili , Farida Bargach , Dalale Mhamdi , Taoufik Ouali , Ahmed Errahmani

We study the evolution of $k=-1$ FLRW cosmological models for two interacting Dark Matter-Dark Energy Models using dynamical system analysis. Since we are interested in late time evolution, the sign of the interaction term is chosen such…

General Relativity and Quantum Cosmology · Physics 2024-11-26 Ashmita , Kinjal Banerjee , Prasanta Kumar Das

We study some properties of the dark degeneracy, which is the fact that what we measure in gravitational experiments is the energy momentum tensor of the total dark sector, and any split into components (as in dark matter and dark energy)…

Cosmology and Nongalactic Astrophysics · Physics 2011-10-17 Alejandro Aviles , Jorge L. Cervantes-Cota

In the framework of general relativity, dark energy was proposed to explain the cosmic acceleration. A pivotal inquiry in cosmology is to determine whether dark energy is the cosmological constant, and if not, the challenge lies in…

Cosmology and Nongalactic Astrophysics · Physics 2025-08-08 Peng-Ju Wu

We study the speed of sound in strong-interaction matter at zero temperature and in density regimes which are expected to be governed by the presence of a color-superconducting gap. At (very) high densities, our analysis indicates that the…

Nuclear Theory · Physics 2024-05-07 Jens Braun , Andreas Geißel , Benedikt Schallmo

We examine an interacting dark matter--variable vacuum energy model for a spatially flat Friedmann-Roberston-Walker spacetime, focusing on the appearance of cosmological singularities such as \emph{big rip, big brake, big freeze}, and…

General Relativity and Quantum Cosmology · Physics 2015-08-19 Luis P. Chimento , Martín G. Richarte

We consider a set of non-linear interactions between dark matter and dark energy which comprises couplings proportional to products of (powers of) the energy densities of both dark components and of the total energy. We demonstrate that…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 Fabiola Arévalo , Anna Paula Ramos Bacalhau , Winfried Zimdahl

A cosmological model of dark energy interacting with dark matter and another general component of the universe is investigated. We found general constraints on these models imposing an accelerated expansion. The same is also studied in the…

High Energy Physics - Phenomenology · Physics 2008-11-26 Norman Cruz , Samuel Lepe , Francisco Pena

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