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The cosmological constant problem is turned around to argue for a new foundational physics postulate underlying a consistent quantum theory of gravity and matter, such as string theory. This postulate is a quantum equivalence principle…

High Energy Physics - Theory · Physics 2008-11-26 Vishnu Jejjala , Djordje Minic

Motivated by the cosmological constant and the coincidence problems, we consider a cosmological model where the cosmological constant $\Lambda_0$ is replaced by a cosmological term $\Lambda(t)$ which is allowed to vary in time. More…

Cosmology and Nongalactic Astrophysics · Physics 2013-07-24 Vincent Poitras

The main consequences of de Sitter Special Relativity to the Standard Cosmological Model of Physical Cosmology are examined. The cosmological constant Lambda appears, in this theory, as a manifestation of the proper conformal current, which…

General Relativity and Quantum Cosmology · Physics 2010-01-08 R. Aldrovandi , J. G. Pereira

The cosmological constant problem is explained by a theory based on the discrete space-time hypothesis. The calculated cosmological constant value is of the order of 10^-52[m]^-2 or equivalent to about 0.7 of the critical mass density. It…

Astrophysics · Physics 2007-05-23 H. M. Mok

We study the effects of a generalized uncertainty principle on the classical and quantum cosmology of a closed Friedmann Universe whose matter content is either a dust or a radiation fluid. More concretely, assuming the existence of a…

General Relativity and Quantum Cosmology · Physics 2015-02-26 S. Jalalzadeh , S. M. M. Rasouli , P. V. Moniz

The Cosmological Principle (CP) -- the notion that the Universe is spatially isotropic and homogeneous on large scales -- underlies a century of progress in cosmology. It is conventionally formulated through the…

It is observed that one of Einstein-Friedmann's equations has formally the aspect of a Sturm-Liouville problem, and that the cosmological constant, $\Lambda$, plays thereby the role of spectral parameter (what hints to its connection with…

Cosmology and Nongalactic Astrophysics · Physics 2012-12-19 Artyom V. Yurov , Artyom V. Astashenok , E. Elizalde

We investigate the global solutions of the Dirac equation on the Anti-de-Sitter Universe. Since this space is not globally hyperbolic, the Cauchy problem is not, {\it a priori}, well-posed. Nevertheless we can prove that there exists…

Mathematical Physics · Physics 2008-11-26 Alain Bachelot

Planck data provide precise constraints on cosmological parameters when assuming the base $\Lambda$CDM model, including a $0.17\%$ measurement of the age of the Universe, $t_0=13.797 \pm 0.023\,{\rm Gyr}$. However, the persistence of the…

Cosmology and Nongalactic Astrophysics · Physics 2021-06-28 Michael Boylan-Kolchin , Daniel R. Weisz

In a recent paper (Vigoureux et al. Int. J. Theor. Phys. 47:928, 2007) it has been suggested that the velocity of light and the expansion of the universe are two aspects of one single concept connecting space and time in the expanding…

Cosmology and Nongalactic Astrophysics · Physics 2011-03-22 David Viennot , Jean-Marie Vigoureux

H.A. Wilson, then R.H. Dicke, proposed to describe gravitation by a spatial change of the refractive index of the vacuum around a gravitational mass. Dicke extended this formalism in order to describe the apparent expansion of the Universe…

General Physics · Physics 2018-06-06 X. Sarazin , F. Couchot , A. Djannati-Atai , M. Urban

An ensemble of pure numbers of order near 10^122 is produced naturally from the fundamental parameters of modern cosmology. This new large-number coincidence problem is resolved by demonstrating implicit physical connections that follow…

General Physics · Physics 2015-06-26 Scott Funkhouser

We study cosmological solutions for the very early universe beginning at the Planck scale for a universe containing radiation, curvature and, as a simplification of a possible scalar field potential, a cosmological constant term. The…

General Relativity and Quantum Cosmology · Physics 2010-01-30 E. Galindo-Dellavalle , G. German , A. de la Macorra

A tetrad-based procedure is presented for solving Einstein's field equations for spherically-symmetric systems; this approach was first discussed by Lasenby et al. in the language of geometric algebra. The method is used to derive metrics…

General Relativity and Quantum Cosmology · Physics 2015-05-27 Roshina Nandra , Anthony N. Lasenby , Michael P. Hobson

We have critically compared different approaches to the cosmological constant problem, which is at the edge of elementary particle physics and cosmology. This problem is deeply connected with the difficulties formulating a theory of quantum…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Stefan Nobbenhuis

In our recently proposed quantum theory of gravity, the universe is made of `atoms' of space-time-matter (STM). Planck scale foam is composed of STM atoms with Planck length as their associated Compton wave-length. The quantum dispersion…

General Relativity and Quantum Cosmology · Physics 2020-08-03 Tejinder P. Singh

The \Lambda CDM standard model, although an excellent parametrization of the present cosmological data, requires two as yet unobserved components, Dark Matter and Dark Energy, for more than 95% of the Universe. Faced to this unsatisfactory…

Cosmology and Nongalactic Astrophysics · Physics 2012-03-01 Aurélien Benoit-Lévy , Gabriel Chardin

With the recent progresses on the Type II supernovae, we attempt to investigate whether there does exist new physics beyond the standard cosmological paradigm, i.e., the cosmological constant $\Lambda$ plus cold dark matter ($\Lambda$CDM).…

Cosmology and Nongalactic Astrophysics · Physics 2019-06-26 Deng Wang

Einstein's most famous equation -- $E=mc^2$ -- generated a short-circuit between the concepts of mass and energy, which also affects other concepts like matter, radiation, and vacuum. Physics currently has a mixture of classical,…

General Physics · Physics 2021-07-21 Luigi Foschini

The current cosmological model, known as the $\Lambda$-Cold Dark Matter model (or $\Lambda$CDM for short) is one of the most astonishing accomplishments of contemporary theoretical physics. It is a well-defined mathematical model which…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-25 Pedro G. Ferreira , Alexander Roskill