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Dark energy in the universe is assumed to be vacuum energy. The energy-momentum of vacuum is described by a scale-dependent cosmological constant. The equations of motion imply for the density of matter (dust) the sum of the usual matter…

General Physics · Physics 2008-11-09 Walter Petry

We examine the embedding of dark energy in high energy models based upon supergravity and extend the usual phenomenological setting comprising an observable sector and a hidden supersymmetry breaking sector by including a third sector…

High Energy Physics - Theory · Physics 2009-10-02 Philippe Brax , Carsten van de Bruck , Jerome Martin , Anne-Christine Davis

We initiate the exploration of the cosmology of dark fifth forces: new forces acting solely on Dark Matter. We focus on long range interactions which lead to an effective violation of the Equivalence Principle on cosmological scales today.…

Cosmology and Nongalactic Astrophysics · Physics 2025-11-19 Maria Archidiacono , Emanuele Castorina , Diego Redigolo , Ennio Salvioni

We show that quantum decoherence, in the context of observational cosmology, can be connected to the cosmic dark energy. The decoherence signature could be characterized by the existence of quantum entanglement between cosmological eras. As…

General Relativity and Quantum Cosmology · Physics 2015-06-15 Salvatore Capozziello , Orlando Luongo

The equation of state characterizing the dark energy component is constrained by combining Chandra observations of the X-ray luminosity of galaxy clusters with independent measurements of the baryonic matter density and the latest…

Astrophysics · Physics 2008-11-26 J. A. S. Lima , J. V. Cunha , J. S. Alcaniz

The postulate of universal local Weyl scaling (conformal) symmetry modifies both general relativity and the Higgs scalar field model. The conformal Higgs model (CHM) acquires a cosmological effect that fits observed accelerating Hubble…

General Relativity and Quantum Cosmology · Physics 2022-02-02 R. K. Nesbet

The mysterious `dark energy' needed to explain the current observations, poses a serious confrontation between fundamental physics and cosmology. The present crisis may be an outcome of the (so far untested) prediction of the general theory…

General Relativity and Quantum Cosmology · Physics 2020-05-19 Ram Gopal Vishwakarma

Dark energy is the component in the present Universe with the greatest abundance, and it is responsible for the accelerating expansion of the Universe. As a result, dark energy is likely to interact with any compact astrophysical object…

General Relativity and Quantum Cosmology · Physics 2022-02-28 Piyali Bhar

I briefly review the cosmological constant problem and the issue of dark energy (or quintessence). Within the framework of quantum field theory, the vacuum expectation value of the energy momentum tensor formally diverges as $k^4$. A cutoff…

Astrophysics · Physics 2008-11-26 Varun Sahni

In this paper, it is shown that the cosmological model that was introduced in a sequence of three earlier papers under the title, A Dust Universe Solution to the Dark Energy Problem, can be used to resolve the problem of the great mismatch…

General Physics · Physics 2010-07-21 James G. Gilson

The discovery of cosmic acceleration has triggered a consistent body of theoretical work aimed at modeling its phenomenology and understanding its fundamental physical nature. In recent years, a powerful formalism that accomplishes both…

Cosmology and Nongalactic Astrophysics · Physics 2020-06-09 Noemi Frusciante , Louis Perenon

We study a universe filled with cold dark matter in the form of discrete inhomogeneities (e.g., galaxies) and dark energy in the form of a continuous perfect fluid. We develop a first-order scalar perturbation theory in the weak gravity…

General Relativity and Quantum Cosmology · Physics 2017-11-07 Maxim Eingorn , Claus Kiefer , Alexander Zhuk

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

We report the detection of dark energy near the Milky Way made with precision observations of the local Hubble flow of expansion. We estimate the local density of dark energy and find that it is near, if not exactly equal to, the global…

Recent observations on Type-Ia supernovae and low density measurement of matter (including dark matter) suggest that the present day universe consists mainly of repulsive-gravity type exotic-matter with negative-pressure often referred as…

General Physics · Physics 2007-05-23 R. C. Gupta

Recently, the observed equation of state for dark energy appears to favor values below $-1$. The tendency implies that the nature of dark energy may be quite different from that of the cosmological constant. In view of the adjustment on the…

Cosmology and Nongalactic Astrophysics · Physics 2021-10-13 Yu-Ping Teng , Wolung Lee , Kin-Wang Ng

Using recent precision measurements of cosmological paramters, we re-examine whether these observations alone, independent of type Ia supernova surveys, are sufficient to imply the existence of dark energy. We find that best measurements of…

Astrophysics · Physics 2008-11-26 Greg Bothun , Stephen D. H. Hsu , Brian Murray

The averaged term of squared vorticity is attributed to accelerated expansion. Cosmological singularity has been a consequence of excessive symmetry of flow, such as "Hubble's law". More realistic one is suggested. Exact dynamic and…

General Physics · Physics 2012-10-30 I. S. Nurgaliev

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 2009-11-06 Dragan Huterer , Michael S. Turner

We revisit the quantum cosmological constant problem and highlight the important roles played by the dS horizon of zero point energy. We argue that fields which are light enough to have dS horizon of zero point energy comparable to the FLRW…

General Relativity and Quantum Cosmology · Physics 2022-09-30 Hassan Firouzjahi
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