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In the following, we offer a novel approach to modeling the observed effects currently attributed to the theoretical concepts of `dark energy', `dark matter', and `dark flow'. Instead of assuming the existence of these theoretical concepts,…

General Physics · Physics 2014-01-06 Michael R. Feldman

The problem of explaining the acceleration of the expansion of the universe and the observational and theoretical difficulties associated with dark matter and dark energy are discussed. The possibility that Einstein gravity does not…

Astrophysics · Physics 2007-05-23 J. W. Moffat

We develop a new approach to building cosmological models, in which small pieces of perturbed Minkowski space are joined together at reflection-symmetric boundaries in order to form a global, dynamical space-time. Each piece of this…

General Relativity and Quantum Cosmology · Physics 2016-04-12 Viraj A. A. Sanghai , Timothy Clifton

In this article we apply the holographic principle for describing in a unifying way the early and the late-time universe, when the general equation of state contains a bulk viscosity. We use the idea of a generalized cut-off holographic…

General Relativity and Quantum Cosmology · Physics 2022-06-24 I. Brevik , A. V. Timoshkin

We consider cosmological implications of the formula for the dark energy density derived by Gurzadyan and Xue which predicts a value fitting the observational one. Cosmological models with varying by time physical constants, namely, speed…

Astrophysics · Physics 2010-11-05 G. V. Vereshchagin

General equations of the unified field theory, obtained using the curved and torsional space-time, are presented. They contain only independent geometrical parameters (metric and connections) of the metric-affine space, and describe the…

General Physics · Physics 2026-01-22 Alex Karpelson

From a hydrodynamicist's point of view the inclusion of viscosity concepts in the macroscopic theory of the cosmic fluid would appear most natural, as an ideal fluid is after all an abstraction (excluding special cases such as…

General Relativity and Quantum Cosmology · Physics 2017-10-30 Iver Brevik , Øyvind Grøn , Jaume de Haro , Sergei D. Odintsov , Emmanuel N. Saridakis

We investigate the properties of a cosmological scenario which undergoes a gravitational phase transition at late times. In this scenario, the Universe evolves according to general relativity in the standard, hot Big Bang picture until a…

Astrophysics · Physics 2013-05-29 Robert R. Caldwell , William Komp , Leonard Parker , Daniel A. T. Vanzella

A U(1) gauge theory turns, on physically motivated models of Quantum Spacetime, into a U($\infty$) gauge theory, hence free classical electrodynamics is no longer free and neutral fields may have electromagnetic interactions. We discuss the…

General Relativity and Quantum Cosmology · Physics 2017-03-22 Sergio Doplicher , Klaus Fredenhagen , Gerardo Morsella , Nicola Pinamonti

We investigate the impact of the generalized uncertainty principle proposed by some approaches to quantum gravity such as string theory and doubly special relativity on the cosmology. Using generalized Poisson brackets, we obtain the…

General Relativity and Quantum Cosmology · Physics 2019-05-22 Mahdi Rashki , Majid Fathi , Behrang Mostaghel , Sahram Jalalzadeh

The discovery that the Universe is accelerating in its expansion has brought the basic concept of cosmic expansion into question. An analysis of the evolution of this concept suggests that the paradigm that was finally settled into prior to…

History and Philosophy of Physics · Physics 2014-09-12 Daryl Janzen

The current expansion of the Universe has been observed to be accelerating, and the widely accepted spatially-flat concordance model of general relativistic cosmology attributes this phenomenon to a constant dark energy, a cosmological…

Cosmology and Nongalactic Astrophysics · Physics 2023-04-13 Shulei Cao

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

In this Essay we construct a concrete, non-perturbative realization of metric reconstruction using quantum-optical model of particle detectors in relativistic quantum information. The non-perturbative approach allows us to realize a version…

General Relativity and Quantum Cosmology · Physics 2023-06-01 Erickson Tjoa

Current observational evidence does not yet exclude the possibility that dark energy could be in the form of phantom energy. A universe consisting of a phantom constituent will be driven toward a drastic end known as the `Big Rip'…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-17 Hoda Ghodsi , Martin A. Hendry , Mariusz P. Dabrowski , Tomasz Denkiewicz

This contribution intends to give a pedagogical introduction to the topic of dark energy (the mysterious agent supposed to drive the observed late time acceleration of the Universe) and to various observational tests which require only…

Astrophysics · Physics 2008-11-26 Ruth Lazkoz

Using the evolution history of the universe, one can make constraint on the parameter space of dynamic dark energy models. We discuss two different parameterized dark energy models. Our results further restrict the combined constraints…

Astrophysics · Physics 2009-11-13 Zhuo-Yi Huang , Bin Wang , Rong-Gen Cai , Ru-Keng Su

There is compelling evidence that the Universe is undergoing a late phase of accelerated expansion. One of the simplest explanations for this behaviour is the presence of dark energy. A plethora of microphysical models for dark energy have…

Cosmology and Nongalactic Astrophysics · Physics 2024-10-25 William J. Wolf , Pedro G. Ferreira

The present work deals with evolution of the fractal model of the Universe in the background of homogeneous and isotropic FLRW space--time geometry. The cosmic substrum is taken as perfect fluid with barotropic equation of state. A general…

General Physics · Physics 2018-11-27 Dipanjana Das , Sourav Dutta , Abdulla Al Mamon , Subenoy Chakraborty

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