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Cosmological data have provided new constraints on the number of neutrino species and the neutrino mass. However these constraints depend on assumptions related to the underlying cosmology. Since a correlation is expected between the number…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-30 Aaron Smith , Maria Archidiacono , Asantha Cooray , Francesco De Bernardis , Alessandro Melchiorri , Joseph Smidt

The evolution of a universe with Brans-Dicke gravity and nonzero curvature is investigated here. We present the equations of motion and their solutions during the radiation dominated era. In a Friedman-Robertson-Walker cosmology we show…

General Relativity and Quantum Cosmology · Physics 2010-11-01 Janna Levin , Katherine Freese

The assumption of a flat Universe that follows the cosmological principle, i.e., that the universe is statistically homogeneous and isotropic at large scales, comprises one of the core foundations of the standard cosmological model --…

Cosmology and Nongalactic Astrophysics · Physics 2025-04-24 Mariana L. S. Dias , Antônio F. B. da Cunha , Carlos A. P. Bengaly , Rodrigo S. Gonçalves , Jonathan Morais

The observed acceleration of the Universe can be explained by modifying general relativity. One such attempt is the nonlocal model of Deser and Woodard. Here we fix the background cosmology using results from the Planck satellite and…

Cosmology and Nongalactic Astrophysics · Physics 2014-09-05 Scott Dodelson , Sohyun Park

We examine an extension of General Relativity with an explicit non-minimal coupling between matter and curvature. The purpose of this work is to present an overview of the implications of the latter to various contexts, ranging from…

General Relativity and Quantum Cosmology · Physics 2014-01-20 Orfeu Bertolami , Jorge Páramos

The flat matter dominated Universe that dominated cosmological model building for much of the past 20 years does not correspond to the Universe in which we live. This has profound implications both for our understanding of dark matter, and…

Astrophysics · Physics 2007-05-23 Lawrence M. Krauss

Cosmic voids, the less dense patches of the Universe, are promising laboratories to extract cosmological information. Thanks to their unique low density character, voids are extremely sensitive to diffuse components such as neutrinos and…

Quantum gravity is sometimes considered as a kind of metaphysical speculation. In this review, we show that, although still extremely difficult to reach, observational signatures can in fact be expected. The early universe is an invaluable…

General Relativity and Quantum Cosmology · Physics 2015-06-17 A. Barrau , T. Cailleteau , J. Grain , J. Mielczarek

In this paper I argue for a reassessment of special relativity. The fundamental theory of relativity applicable in this Universe has to be consistent with the existence of the massive Universe, and with the effects of its gravitational…

General Relativity and Quantum Cosmology · Physics 2007-05-23 C. S. Unnikrishnan

The lower limit on the age of the universe derived from globular cluster dating techniques, which previously strongly motivated a non-zero cosmological constant, has now been dramatically reduced, allowing consistency for a flat matter…

Astrophysics · Physics 2011-02-11 Lawrence M. Krauss

The next generation of cosmological surveys will operate over unprecedented scales, and will therefore provide exciting new opportunities for testing general relativity. The standard method for modelling the structures that these surveys…

General Relativity and Quantum Cosmology · Physics 2018-03-28 Sophia R. Goldberg , Christopher Gallagher , Timothy Clifton

As evidenced by a great number of works, it is common practice to assume that the Universe is flat. However, the majority of studies which make use of observational data to constrain the curvature density parameter are premised on the…

General Relativity and Quantum Cosmology · Physics 2019-07-18 Christine R. Farrugia , Joseph Sultana

We investigate structure formation in a one dimensional model of a matter-dominated universe using a quasi-newtonian formulation. In addition to dark matter, luminous matter is introduced to examine the potential bias in the distributions.…

Cosmology and Nongalactic Astrophysics · Physics 2016-06-29 Yui Shiozawa , Bruce N. Miller

Using a gauge-invariant formalism we derive and solve the perturbed cosmological equations for the BSBM theory of varying fine structure 'constant'. We calculate the time evolution of inhomogeneous perturbations of the fine structure…

General Relativity and Quantum Cosmology · Physics 2009-11-07 John D. Barrow , D. F. Mota

The distribution of the non-luminous matter in galaxies of different luminosity and Hubble type is much more than a proof of the existence of dark particles governing the structures of the Universe. Here, we will review the complex but…

Astrophysics of Galaxies · Physics 2019-02-25 Paolo Salucci

Cosmic voids are low-mass-density regions on intergalactic scales. They are where cosmic expansion and acceleration are most dominant, important places to understand and analyze for cosmology. This entry summarises theoretical underpinnings…

Cosmology and Nongalactic Astrophysics · Physics 2026-05-01 Yan-Chuan Cai , Mark Neyrinck

We investigate the propagation of certain non-plane wave solutions to Maxwell's equations in both flat and curved spacetimes. We find that such solutions (or rather parts of them) exhibit accelerative behaviour, and in particular do not…

History and Philosophy of Physics · Physics 2023-11-16 Felipe A. Asenjo , Sergio A. Hojman , Niels Linnemann , James Read

Quantum cosmology in the presence of a fundamental minimal length is analyzed in the context of the flat isotropic and the Taub cosmological models. Such minimal scale comes out from a generalized uncertainty principle and the quantization…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Marco Valerio Battisti , Giovanni Montani

We explore the dynamics and evolution of the Universe at early and late times, focusing on both dark energy and extended gravity models and their astrophysical and cosmological consequences. Modified theories of gravity not only provide an…

We revisit the observational constraints on spatial curvature following recent claims that the Planck data favour a closed Universe. We use a new and statistically powerful Planck likelihood to show that the Planck temperature and…

Cosmology and Nongalactic Astrophysics · Physics 2020-06-03 George Efstathiou , Steven Gratton