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We study the cosmology with the running dark energy. The parametrization of dark energy with the respect to the redshift is derived from the first principles of quantum mechanics. Energy density of dark energy is obtained from the quantum…

General Relativity and Quantum Cosmology · Physics 2017-08-23 Aleksander Stachowski , Marek Szydlowski , Krzysztof Urbanowski

We investigate the possibility of using cosmological observations to probe and constrain an imperfect dark energy fluid. We consider a general parameterization of the dark energy component accounting for an equation of state, speed of sound…

Astrophysics · Physics 2008-12-18 D. F. Mota , J. R. Kristiansen , T. Koivisto , N. E. Groeneboom

Observations of distant supernovae indicate that the Universe is now in a phase of accelerated expansion the physical cause of which is a mystery. Formally, this requires the inclusion of a term acting as a negative pressure in the…

The modified F(R)-scalar-Gauss-Bonnet gravity is proposed as dark energy model. The reconstruction program for such theory is developed. It is explicitly demonstrated that the known classical universe expansion history (deceleration epoch,…

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

We here investigate the model of interacting dark energy in the context of five dimensional brane cosmology. The effective equations of state of dark energy are evaluated for various choices of the variable time dependent cosmological…

General Relativity and Quantum Cosmology · Physics 2016-11-15 Mubasher Jamil

The presence of dark energy in the Universe is inferred directly from the accelerated expansion of the Universe, and indirectly, from measurements of cosmic microwave background (CMB) anisotropy. Dark energy contributes about 2/3 of the…

Astrophysics · Physics 2011-05-05 Dragan Huterer , Michael S. Turner

A so called "ghost dark energy" was recently proposed to explain the present acceleration of the universe expansion. The energy density of ghost dark energy, which originates from Veneziano ghost of QCD, is proportional to the Hubble…

General Physics · Physics 2011-11-04 Ahamd Sheykhi , Ali Bagheri

A new dark energy model called "ghost dark energy" was recently suggested to explain the observed accelerating expansion of the universe. This model originates from the Veneziano ghost of QCD. The dark energy density is proportional to…

High Energy Physics - Theory · Physics 2015-03-19 A. Sheykhi , M. Sadegh Movahed

Understanding the origin of the accelerated expansion of the Universe poses one of the greatest challenges in physics today. Lacking a compelling fundamental theory to test, observational efforts are targeted at a better characterization of…

Cosmology and Nongalactic Astrophysics · Physics 2010-12-28 Tracy Holsclaw , Ujjaini Alam , Bruno Sanso , Herbert Lee , Katrin Heitmann , Salman Habib , David Higdon

I briefly review our current understanding of dark matter and dark energy. The first part of this paper focusses on issues pertaining to dark matter including observational evidence for its existence, current constraints and the `abundance…

Astrophysics · Physics 2022-07-19 Varun Sahni

In this paper, we point out thermodynamical description of ghost dark energy and its generalization to the early universe. Thereinafter, we find expressions for the entropy changes of these dark energy candidates. In addition, considering…

General Relativity and Quantum Cosmology · Physics 2015-05-06 M. Honarvaryan , A. Sheykhi , H. Moradpour

Combined measurements of Baryon Acoustic Oscillations (BAO) from the Dark Energy Spectroscopic Survey (DESI), the Cosmic Microwave Background (CMB) and Type Ia Supernovae (SN Ia), have recently challenged the $\Lambda$-Cold Dark Matter…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-10 Rayff de Souza , Agripino Sousa-Neto , Javier E. González , Jailson Alcaniz

We consider the generalized particle dynamics, proposed by us, in brane world formalisms for an asymptotically anti de Sitter background. The present framework results in a new model that accounts for the late acceleration of the universe.…

Cosmology and Nongalactic Astrophysics · Physics 2011-07-25 Sudipta Das , Subir Ghosh , Jan-Willem van Holten , Supratik Pal

We place observational constraints on models with the late-time cosmic acceleration based on a number of parametrizations allowing fast transitions for the equation of state of dark energy. In addition to the model of Linder and Huterer…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Antonio De Felice , Savvas Nesseris , Shinji Tsujikawa

It is generally argued that the present cosmological observations support the accelerating models of the universe, as driven by the cosmological constant or `dark energy'. We argue here that an alternative model of the universe is possible…

Astrophysics · Physics 2009-11-07 J. V. Narlikar , R. G. Vishwakarma , G. Burbidge

The universe's current acceleration is a pretty recent phenomenon in cosmological time scales. This means that the modes that have left our horizon since the beginning of the contemporary acceleration phase, have not really reached the…

High Energy Physics - Theory · Physics 2023-08-23 A. Ashoorioon , A. Yousefi-Sostani

Constantly accumulating observational data continue to confirm that about 70% of the energy density today consists of dark energy responsible for the accelerated expansion of the Universe. We present recent observational bounds on dark…

Cosmology and Nongalactic Astrophysics · Physics 2013-11-12 Shinji Tsujikawa

It has been only ~15 years since the discovery of dark energy (although some may argue there were strong indications even earlier). In the short time since measurements of type Ia supernovae indicated an accelerating universe, many other…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-19 Tamara M. Davis

We study a phenomenological dark energy model which is rooted in the Veneziano ghost of QCD. In this dark energy model, the energy density of dark energy is proportional to Hubble parameter and the proportional coefficient is of the order…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 Rong-Gen Cai , Qiping Su , Zhong-Liang Tuo , Hong-Bo Zhang

This paper focuses on developing a generalized ghost dark energy model $f\mathcal{(Q,T)}$ through the correspondence scheme for a non-interacting scenario involving pressureless matter and a power-law scale factor. We analyze the…

General Relativity and Quantum Cosmology · Physics 2024-09-06 M. Sharif , Iqra Ibrar
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