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We discuss a cosmological model where the universe shrinks rather than expands during the radiation and matter dominated periods. Instead, the Planck mass and all particle masses grow exponentially, with the size of atoms shrinking…

Cosmology and Nongalactic Astrophysics · Physics 2013-11-13 C. Wetterich

From the axiom of the unrestricted repeatability of all experiments, Bondi and Gold argued that the universe is in a stable, self-perpetuating equilibrium state. This concept generalizes the usual cosmological principle to the perfect…

Astrophysics · Physics 2007-05-23 Thomas B. Andrews

Recently, a new framework for describing the multiverse has been proposed which is based on the principles of quantum mechanics. The framework allows for well-defined predictions, both regarding global properties of the universe and…

High Energy Physics - Theory · Physics 2013-05-29 Grant Larsen , Yasunori Nomura , H. L. L. Roberts

In order to account for the observable Universe, any comprehensive theory or model of cosmology must draw from many disciplines of physics, including gauge theories of strong and weak interactions, the hydrodynamics and microphysics of…

General Relativity and Quantum Cosmology · Physics 2015-06-25 Peter Anninos

This paper has two parts, for a specific multiverse, and for the origin of our universe as it resulted from that multiverse. The first is based on the Planck domain and a Chandrasekhar equation that have quantum, relativity, gravity, and…

General Physics · Physics 2009-12-31 Tom Gehrels

Traditional ideas for testing unification involve searching for the decay of the proton and its branching modes. We point out that several astrophysical experiments are now reaching sensitivities that allow them to explore supersymmetric…

High Energy Physics - Phenomenology · Physics 2010-04-15 Asimina Arvanitaki , Savas Dimopoulos , Sergei Dubovsky , Peter W. Graham , Roni Harnik , Surjeet Rajendran

Particle physics has evolved a coherent model that characterizes forces and particles at the most elementary level. This Standard Model, built from many theoretical and experimental studies, is in excellent accord with almost all current…

High Energy Physics - Phenomenology · Physics 2008-11-26 Mary K. Gaillard , Paul D. Grannis , Frank J. Sciulli

Modern observations based on general relativity indicate that the spatial geometry of the expanding, large-scale Universe is very nearly Euclidean. This basic empirical fact is at the core of the so-called "flatness problem", which is…

General Relativity and Quantum Cosmology · Physics 2018-10-24 Marc Holman

A well-known topic within the philosophy of physics is the problem of fine-tuning: the fact that the universal constants seem to take non-arbitrary values in order for live to thrive in our Universe. In this paper we will talk about this…

History and Philosophy of Physics · Physics 2024-09-06 Julian De Vuyst

Time is a parameter playing a central role in our most fundamental modeling of natural laws. Relativity theory shows that the comparison of times measured by different clocks depends on their relative motions and on the strength of the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-11 Pierre Magain , Clémentine Hauret

In physical theories, boundary or initial conditions play the role of selecting special situations which can be described by a theory with its general laws. Cosmology has long been suspected to be different in that its fundamental theory…

General Relativity and Quantum Cosmology · Physics 2015-06-25 Martin Bojowald

The tired-light cosmology is considered in the framework of Kaluza-Klein theory in 5D. The solution of the five-dimensional semi-classical Einstein equations with nonzero five-dimensional energy-momentum tensor gives density of matter in…

General Relativity and Quantum Cosmology · Physics 2007-05-23 W. B. Belayev

A phenomenological approach is proposed to the problem of universe accelerated expansion and of the dark energy nature. A general class of models is introduced whose energy density depends on the redshift $z$ in such a way that a smooth…

Astrophysics · Physics 2009-11-10 V. F. Cardone , A. Troisi , S. Capozziello

From classical mechanics to quantum field theory, the physical facts at one point in space are held to be independent of those at other points in space. I propose that we can usefully challenge this orthodoxy in order to explain otherwise…

Quantum Physics · Physics 2012-12-03 Steven Weinstein

Assuming that Quantum Mechanics is universal and that it can be applied over all scales, then the Universe is allowed to be in a quantum superposition of states, where each of them can correspond to a different space-time geometry. How can…

General Relativity and Quantum Cosmology · Physics 2024-02-27 José Luis Gaona-Reyes , Lucía Menéndez-Pidal , Mir Faizal , Matteo Carlesso

One signature of an expanding universe is the time-variation of the cosmological abundances of its different components. For example, a radiation-dominated universe inevitably gives way to a matter-dominated universe, and critical moments…

Cosmology and Nongalactic Astrophysics · Physics 2022-02-09 Keith R. Dienes , Lucien Heurtier , Fei Huang , Doojin Kim , Tim M. P. Tait , Brooks Thomas

It is shown that the homogeneous and isotropic Universe is spatially flat in the limit which takes into account the moments of infinitely large orders of probabilistic distribution of a scale factor with respect to its mean value in the…

Astrophysics · Physics 2007-12-05 V. E. Kuzmichev , V. V. Kuzmichev

In models where the constants of Nature can take more than one set of values, the cosmological wave function $\psi$ describes an ensemble of universes with different values of the constants. The probability distribution for the constants…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Alexander Vilenkin

Big Bang models of the Universe predict rapid domination by curvature, a paradox known as the flatness problem. Solutions to this problem usually leave the Universe exactly flat for every practical purpose. Explaining a nearly but not…

Astrophysics · Physics 2009-10-31 John D. Barrow , Joao Magueijo

We discuss the fundamental constants of physics in the Standard Model and possible changes of these constants on the cosmological time scale. The Grand Unification of the strong, electromagnetic and weak interactions implies relations…

High Energy Physics - Phenomenology · Physics 2009-07-22 H. Fritzsch