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In this paper, we propose a model in which an additional pressure due to the effects of the entropic force is added to the ideal fluid. Furthermore, we obtain the dynamic equation in the FRW universe which contains the quantum gravitational…

High Energy Physics - Theory · Physics 2016-03-08 Fei-Quan Tu , Yi-Xin Chen

Consistency relations between growth of structure and expansion history observables exist for any physical explanation of cosmic acceleration, be it a cosmological constant, scalar field quintessence, or a general component of dark energy…

Astrophysics · Physics 2010-04-15 Michael J. Mortonson , Wayne Hu , Dragan Huterer

The relationship between the cosmic microwave background radiation temperature and the redshift, i.e., the $T$--$z$ relation, is examined in a phenomenological dissipative model. The model contains two constant terms, as if a nonzero…

Cosmology and Nongalactic Astrophysics · Physics 2015-08-10 Nobuyoshi Komatsu , Shigeo Kimura

Astronomical observations have shown that the expansion of the universe is at present accelerating, in a way consistent with the presence of a positive cosmological constant. This is a major puzzle, because we do not understand: why the…

Astrophysics · Physics 2007-05-23 Jordi Miralda-Escude

We discuss the first results from two successful simulations of galaxy formation within a cosmological volume. With over 2000 large objects forming in each we have sufficient numbers to reliably produce both galaxy correlation and…

Fluctuations in the intensity and polarization of the cosmic microwave background (CMB) and the large-scale distribution of matter in the universe each contain clues about the nature of the earliest moments of time. The next generation of…

Cosmic acceleration is explained quantitatively, purely in general relativity, as an apparent effect due to quasilocal gravitational energy differences that arise in the decoupling of bound systems from the global expansion of the universe.…

General Relativity and Quantum Cosmology · Physics 2008-11-26 David L. Wiltshire

For two decades the hot big-bang model has been referred to as the standard cosmology -- and for good reason. For just as long cosmologists have known that there are fundamental questions that are not addressed by the standard cosmology and…

Astrophysics · Physics 2007-05-23 Michael S. Turner

A non--minimally coupled quintessence model is investigated and the conditions for a stationary solution to the coincidence problem are obtained. For a conformally coupled scalar field and dissipative matter, a general solution possessing…

Astrophysics · Physics 2009-11-10 Luis P. Chimento , Alejandro S. Jakubi , Diego Pavon

According to the Big Bang theory and as a consequence of adiabatic expansion of the Universe, the temperature of the cosmic microwave background (CMB) increases linearly with redshift. This relation is, however, poorly explored, and…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 S. Muller , A. Beelen , J. H. Black , S. J. Curran , C. Horellou , S. Aalto , F. Combes , M. Guelin , C. Henkel

This paper proposes a systematic study of cosmological signatures of modifications of gravity via the presence of a scalar field with a multiplicative coupling to the electromagnetic Lagrangian. We show that, in this framework, variations…

Cosmology and Nongalactic Astrophysics · Physics 2015-01-27 A. Hees , O. Minazzoli , J. Larena

BVRI data for the majority of the objects of the RC catalogue with steep spectra and $m_R<24^m$ are presented. These data have been used to estimate colour redshifts and the age of stellar systems of host galaxies. By way of example of…

In all Friedman models, the cosmological redshift is widely interpreted as a consequence of the general-relativistic phenomenon of EXPANSION OF SPACE. Other commonly believed consequences of this phenomenon are superluminal recession…

Astrophysics · Physics 2009-11-11 Michal Chodorowski

Constancy of the speed of light together with the Hubble law lead in a doctrine of expanding universe to a conclusion that universe evolution is not only an expansion of space but also a deceleration of the course of physical time (Taganov,…

General Physics · Physics 2008-07-28 Igor N. Taganov

The thermodynamic and dynamical properties of a variable dark energy model with density scaling as rho_x \propto (1+z)^m, z being the redshift, are discussed following the outline of Jetzer et al. This kind of models are proven to lead to…

Cosmology and Nongalactic Astrophysics · Physics 2011-09-08 Philippe Jetzer , Crescenzo Tortora

Observational constraints guide one forcefully to examine models in which the matter density is substantially less than critical density. Particularly noteworthy are those which are consistent with inflation. For these models, microwave…

Astrophysics · Physics 2007-05-23 J. P. Ostriker , Paul J. Steinhardt

One possibility for explaining the apparent accelerating expansion of the universe is that we live in the center of a spherically inhomogeneous universe. Although current observations cannot fully distinguish $\Lambda$CDM and these…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 Kent Yagi , Atsushi Nishizawa , Chul-Moon Yoo

Almost all cosmologists accept nowadays that the redshift of the galaxies is due to the expansion of the Universe (cosmological redshift), plus some Doppler effect of peculiar motions, but can we be sure of this fact by means of some other…

Cosmology and Nongalactic Astrophysics · Physics 2015-01-08 Martin Lopez-Corredoira

In this paper we describe the evolution of the Universe in terms of the Friedmann equation, which takes into account of the composition and geometry of the Universe. The dependence of the solution on the geometry and composition for…

Popular Physics · Physics 2020-11-02 Vinicius S. Aderaldo , Victor P. Goncalves

Astrophysical data reformulated in the units of the relative Paris meter and running Planck mass are used for restoration of a conformal version of the unified theory where the absolute Planck mass belongs to ordinary initial data (like the…

High Energy Physics - Phenomenology · Physics 2007-05-23 Victor Pervushin
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