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Evolution of cosmological perturbations is considered in the model with dynamical dark energy which non-gravitationally interacts with dark matter. The dark energy equation of state parameter (EoS) is varying in time and is parameterized by…

Cosmology and Nongalactic Astrophysics · Physics 2020-11-09 R. Neomenko , B. Novosyadlyj

The equation of state (EOS) of the dark energy is the key parameter to study the nature of the dark energy from the observation. Though the dark energy is found to be well consistent with the cosmological constant with a constant EOS of…

Cosmology and Nongalactic Astrophysics · Physics 2015-09-24 Shi Qi

In this paper we study a model of cosmic evolution, assuming that the different components of the universe could interact between them any time. An effective equation of state (EOS) for the universe has been used as well. A particular…

Cosmology and Nongalactic Astrophysics · Physics 2010-03-17 Alberto C. Balfagon , Raul Ramirez-Satorras

The dark energy universe equation of state (EOS) with inhomogeneous,Hubble parameter dependent term is considered. The motivation to introduce such a term comes from time-dependent viscosity considerations and modifications of general…

High Energy Physics - Theory · Physics 2008-11-26 Shin'ichi Nojiri , Sergei D. Odintsov

The time evolution of cosmological parameters in early Universe at the deconfinement transition is studied by an equation of state (EoS) which takes into account the finite baryon density and the background magnetic field. The non…

High Energy Physics - Phenomenology · Physics 2015-09-30 Paolo Castorina , Vincenzo Greco , Salvatore Plumari

We investigate the cosmological implications of a generalized total equation of state (EoS) model by constraining its parameters using observational datasets to effectively characterize the universe's expansion history and its dynamic…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-14 M. Koussour , S. Bekov , A. Syzdykova , S. Muminov , I. Ibragimov , J. Rayimbaev

In the symmetric teleparallel gravity framework, we study the cosmic dynamics of the universe with dark energy equation of state (EoS) parameter having non-linear forms. The non-metricity scalar induced by the dark energy EoS parameter…

General Relativity and Quantum Cosmology · Physics 2025-07-10 Romanshu Garg , G. P. Singh , Ashutosh Singh

A generally parameterized equation of state (EOS) is investigated in the cosmological evolution with bulk viscosity media modelled as dark fluid, which can be regarded as a unification of dark energy and dark matter. Compared with the case…

Astrophysics · Physics 2009-11-13 J. Ren , Xin He Meng

The experimental evidence that the equation of state (EOS) of the dark energy (DE) could be evolving with time/redshift (including the possibility that it might behave phantom-like near our time) suggests that there might be dynamical DE…

General Relativity and Quantum Cosmology · Physics 2009-11-11 Joan Sola

In this work we present a new scheme to study the tachyon dark energy model using dynamical systems analysis by considering parametrization of the equation of state(EoS) of the dark energy. Both the canonical and phantom field dynamics are…

General Relativity and Quantum Cosmology · Physics 2023-03-21 Saddam Hussain , Saikat Chakraborty , Nandan Roy , Kaushik Bhattacharya

The cosmological model with an interaction between dynamical quintessence dark energy and cold dark matter is considered. Evolution of a dark energy equation of state parameter is defined by a dark energy adiabatic sound speed and a dark…

Cosmology and Nongalactic Astrophysics · Physics 2023-11-08 Roman Neomenko

Determining the mechanism behind the current cosmic acceleration constitutes a major question nowadays in theoretical physics. If the dark energy route is taken, this problem may potentially bring to light new insights not only in Cosmology…

Astrophysics · Physics 2009-07-09 E. M. Barboza , J. S. Alcaniz

While there is mounting evidence in all fronts of experimental cosmology for a non-vanishing dark energy component in the Universe, we are still far away from understanding its ultimate nature. A fundamental cosmological constant, Lambda,…

Astrophysics · Physics 2008-11-26 Joan Sola , Hrvoje Stefancic

We explore the cosmological evolution of equation of state (EoS) for dark energy in g-essence models, the action of which is described by a function of both the canonical kinetic term of both the scalar and fermionic fields. We examine…

General Physics · Physics 2013-05-06 Kazuharu Bamba , Olga Razina , Koblandy Yerzhanov , Ratbay Myrzakulov

In this paper, we present a dynamical system analysis of the tachyon dark energy model by parametrization of the equation of state (EoS) of the dark energy. The choice of parametrization can constrain the form of the field potential, and as…

General Relativity and Quantum Cosmology · Physics 2023-06-21 Saddam Hussain , Saikat Chakraborty , Nandan Roy , Kaushik Bhattacharya

This paper investigates the thermodynamic evolution of the universe within the framework of a quadratic equation of state (EoS). Building upon the basis of the quadratic EoS model, as a phenomenological extension to dark energy models, we…

Cosmology and Nongalactic Astrophysics · Physics 2025-10-28 A. Shahriar , M. Abbasiyan-Motlaq , M. Mohsenzadeh , E. Yusofi

Time variable cosmological constant (TVCC) of holographic origin with interaction in Brans-Dicke theory is discussed in this paper. We investigate some characters for this model, and show the evolutions of deceleration parameter and…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Jianbo Lu , Lina Ma , Molin Liu , Yabo Wu

In this work we study the cosmological evolution of a dark energy model with two scalar fields, i.e. the tachyon and the phantom tachyon. This model enables the equation of state $w$ to change from $w>-1$ to $w<-1$ in the evolution of the…

Astrophysics · Physics 2009-12-04 Shang-Gang Shi , Yun-Song Piao , Cong-Feng Qiao

Multiacceleration scenario can be used to solve the cosmological coincidence problem. In this paper, after considering the early radiation era, we revisit the cosmological dynamics of the oscillating dark energy model proposed in…

General Relativity and Quantum Cosmology · Physics 2020-10-08 S. X. Tian

We investigate an interacting quintessence dark energy - dark matter scenario and its impact on structure formation by analyzing the evolution of scalar perturbations. The interaction is introduced by incorporating a non-zero source term…

General Relativity and Quantum Cosmology · Physics 2025-02-06 Anirban Chatterjee , Abhijit Bandyopadhyay , Debasish Majumdar
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