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``One could imagine that as a result of enormously extended astronomical experience, the entire universe consists of countless identical copies of our Milky Way, that the infinite space can be partitioned into cubes each containing an…

Astrophysics · Physics 2007-05-23 Jean-Pierre Luminet , Boudewijn F. Roukema

If the topology of the universe is compact we show how it significantly changes our assessment of the naturalness of the observed structure of the universe and the likelihood of its present state of high isotropy and near flatness arising…

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

The Standard Model of Particle Physics (SMPP) is an enormously successful description of high energy physics, driving ever more precise measurements to find "physics beyond the standard model", as well as providing motivation for developing…

Astrophysics · Physics 2015-06-24 Douglas Scott

We revise the statistical properties of the primordial cosmological density anisotropies that, at the time of matter radiation equality, seeded the gravitational development of large scale structures in the, otherwise, homogeneous and…

High Energy Physics - Phenomenology · Physics 2008-11-26 David H. Oaknin

We explore the effects of a positive cosmological constant on astrophysical and cosmological configurations described by a polytropic equation of state. We derive the conditions for equilibrium and stability of such configurations and…

Astrophysics · Physics 2008-11-26 Andres Balaguera-Antolinez , David F. Mota , Marek Nowakowski

The universe we observe is homogeneous on super-horizon scales, leading to the ``cosmic homogeneity problem''. Inflation alleviates this problem but cannot solve it within the realm of conservative extrapolations of classical physics. A…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Mark Trodden , Tanmay Vachaspati

Based on an analysis of the entropy associated to the vacuum quantum fluctuations, we show that the holographic principle, applied to the cosmic scale, constitutes a possible explanation for the observed value of the cosmological constant,…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Saulo Carneiro

Supernovae observations strongly support the presence of a cosmological constant, but its value, which we will call apparent, is normally determined assuming that the Universe can be accurately described by a homogeneous model. Even in the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 Antonio Enea Romano , Pisin Chen

The current cosmological dark sector (dark matter plus dark energy) is challenging our comprehension about the physical processes taking place in the Universe. Recently, some authors tried to falsify the basic underlying assumptions of such…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 V. C. Busti , J. A. S. Lima

A general principle of non-equivalence for bodies and observers in different G potentials (GP) was derived from correspondence of the Einstein's equivalence principle either with optical physics or with gravitational experiments in which…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Rafael A. Vera

The holographic principle sets an upper bound on the total entropy content of the Universe. Within the limits of a Newtonian approximation, a quantum-mechanical model is presented to describe the cosmological fluid. Under the assumption…

General Relativity and Quantum Cosmology · Physics 2023-07-19 P. Fernandez de Cordoba , J. M. Isidro

In this work a satisfactory, simple theoretical prediction of the data corresponding to observationally (by fine tuning condition) estimated value of the cosmological constant is given. It is supposed (in conceptually analogy with…

Astrophysics · Physics 2007-12-27 Vladan Pankovic , Simo Ciganovic , Jovan Ivanovic , Rade Glavatovic , Petar Grujic

In the standard cosmological model the dark energy (DE) and nonrelativistic (NR) matter densities are observationally determined to be comparable at the present time, in spite of their greatly different evolution histories. This `cosmic…

Cosmology and Nongalactic Astrophysics · Physics 2022-08-30 Meir Shimon

Advantages of inhomogeneous cosmological models that are exact solutions of Einstein's equations over linearised perturbations of homogeneous models are presented. Examples of effects that can be described in the inhomogeneous ones are…

General Relativity and Quantum Cosmology · Physics 2011-12-05 Andrzej Krasiński

We consider the possibility of describing the Higgs effect in unified theories without the Higgs potential in the presence of the Einstein gravity with the conformal gravity-scalar coupling under the assumption of homogeneous matter…

General Relativity and Quantum Cosmology · Physics 2007-05-23 V. N. Pervushin , V. I Smirichinski

The linear cosmological perturbation theory of an almost homogeneous and isotropic perfect fluid universe is reconsidered and formally simplified by introducing new covariant and gauge-invariant variables with physical interpretations on…

General Relativity and Quantum Cosmology · Physics 2011-07-19 Winfried Zimdahl

A fundamental presupposition of modern cosmology is the Copernican Principle; that we are not in a central, or otherwise special region of the Universe. Studies of Type Ia supernovae, together with the Copernican Principle, have led to the…

Astrophysics · Physics 2009-11-13 Timothy Clifton , Pedro G. Ferreira , Kate Land

One of the fundamental assumptions of the standard $\Lambda$CDM cosmology is that, on large scales, all the matter-energy components of the Universe share a common rest frame. This seems natural for the visible sector, that has been in…

Cosmology and Nongalactic Astrophysics · Physics 2019-06-26 J. A. R. Cembranos , A. L. Maroto , H. Villarrubia-Rojo

This is a short summary of a project to construct a first principles cosmology of the Standard Model epoch, the period starting shortly before the electro-weak transition. The cosmology is derived from a simple initial state entirely within…

Cosmology and Nongalactic Astrophysics · Physics 2022-04-14 Daniel Friedan

A comparison of the standard models in particle physics and in cosmology demonstrates that they are not compatible, though both are well established. Basics of modern cosmology are briefly reviewed. It is argued that the measurements of the…

High Energy Physics - Phenomenology · Physics 2008-11-26 A. D. Dolgov