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I describe an approach which connects classical gravity with the quantum microstructure of spacetime. The field equations arise from maximizing the density of states of matter plus geometry. The former is identified using the thermodynamics…

General Relativity and Quantum Cosmology · Physics 2017-08-25 T. Padmanabhan

We present a model in which the cosmological constant emerges as a purely geometric effect from the four-dimensional compactification of five-dimensional Einstein-Chern-Simons gravity. The compactification of the extra dimension generates…

General Relativity and Quantum Cosmology · Physics 2026-04-03 M. Cataldo , S. Lepe , C. Riquelme , P. Salgado

It is shown that the cosmological constant links the roots both of General Relativity and Newtonian gravity via the general function satisfying Newton's theorem according to which the gravitating sphere acts as a point mass situated in its…

General Relativity and Quantum Cosmology · Physics 2019-01-10 V. G. Gurzadyan

The conventional cold, particle interpretation of dark matter (CDM) still lacks laboratory support and struggles with the basic properties of common dwarf galaxies, which have surprisingly uniform central masses and shallow density…

Astrophysics of Galaxies · Physics 2014-06-26 Hsi-Yu Schive , Tzihong Chiueh , Tom Broadhurst

The main foundations of the standard $\Lambda $CDM model of cosmology are that: 1) The redshifts of the galaxies are due to the expansion of the Universe plus peculiar motions; 2) The cosmic microwave background radiation and its…

Cosmology and Nongalactic Astrophysics · Physics 2017-03-08 Martin Lopez-Corredoira

A model for gravitational collapse where the event horizon is a quantum critical phase transition is extended to provide an explanation for the origin of the observable universe, where the expanding universe that we observe today was…

General Relativity and Quantum Cosmology · Physics 2016-02-09 George Chapline , James Barbieri

There is something unknown in the cosmos. Something big. Which causes the acceleration of the Universe expansion, that is perhaps the most surprising and unexpected discovery of the last decades, and thus represents one of the most pressing…

General Physics · Physics 2013-04-18 M. Villata

In this essay, we present a new understanding of the cosmological constant problem, built upon the realization that the vacuum energy density can be expressed in terms of a phase space volume. We introduce a UV-IR regularization which…

High Energy Physics - Theory · Physics 2023-03-31 Laurent Freidel , Jerzy Kowalski-Glikman , Robert G. Leigh , Djordje Minic

A phenomenological model is proposed to explain the recent observed cosmological variation of the fine structure constant as an effect of the quantum vacuum, assuming a flat universe with cosmological constant $\Lambda$ in the cases…

Astrophysics · Physics 2010-12-17 Antonio F. Rañada

We note that in general there exist two basic aspects in any branch of physics, including cosmology - one dealing with the attributes of basic constituents and forces of nature, the other dealing with how structures arise from them and how…

General Relativity and Quantum Cosmology · Physics 2007-05-23 B. L. Hu

We argue that there is an intrinsic noise on measurements of the equation of state parameter $w=p/\rho$ from large-scale structure around us. The presence of the large-scale structure leads to an ambiguity in the definition of the…

Cosmology and Nongalactic Astrophysics · Physics 2014-04-29 Wessel Valkenburg , Martin Kunz , Valerio Marra

The $\Lambda$CDM model, or concordance cosmology, as it is often called, is a paradigm at its maturity. It is clearly able to describe the universe at large scale, even if some issues remain open, such as the cosmological constant problem ,…

Cosmology and Nongalactic Astrophysics · Physics 2017-03-27 Antonino Del Popolo , Morgan Le Delliou

The cosmological constant (CC, $\Lambda$) problem represents a remarkable discrepancy of about 120 orders of magnitude between the observed dark energy and its natural expectation from quantum field theory. This paper synthesizes two…

High Energy Physics - Theory · Physics 2026-04-30 Andrea Addazi , Salvatore Capozziello , Giuseppe Meluccio

Even when completely and consistently formulated, a fundamental theory of physics and cosmological boundary conditions may not give unambiguous and unique predictions for the universe we observe; indeed inflation, string/M theory, and…

High Energy Physics - Theory · Physics 2009-10-07 Anthony Aguirre , Max Tegmark

A mechanism for suppressing the cosmological constant is developed, based on an analogy with a superconducting phaseshift in which free fermions coupled perturbatively to a weak gravitational field are in an unstable false vacuum state. The…

High Energy Physics - Theory · Physics 2007-05-23 Stephon Alexander , Manasse Mbonye , John Moffat

A finite quantum gravity theory is used to resolve the cosmological constant problem. A fundamental quantum gravity scale, \Lambda_G \leq 10^{-3} eV, is introduced above which the quantum corrections to the vacuum energy density coupled to…

High Energy Physics - Phenomenology · Physics 2007-05-23 J. W. Moffat

In a previous work [1], it was speculated that the lack of homogeneity of the large-scale structure of the universe may be due to quantum fluctuations of space in the early universe. In [1], this was argued for a Friedmann-type universe for…

General Physics · Physics 2019-10-28 Benito Hernández-Bermejo

Gravitation as a fundamental interaction that governs all phenomena at large and very small scales, but still not well understood at a quantum level, is a cardinal missing link in unification of all physical interactions. Discovery of the…

General Relativity and Quantum Cosmology · Physics 2009-11-30 V. N. Melnikov

In this paper we provide both a diagnosis and resolution of the cosmological constant problem, one in which a large (as opposed to a small) cosmological constant $\Lambda$ can be made compatible with observation. We trace the origin of the…

Astrophysics · Physics 2009-10-31 Philip D. Mannheim

The cosmological constant is the most economical candidate for dark energy. No other approach really alleviates the difficulties faced by the cosmological constant because, in all other attempts to model the dark energy, one still has to…

General Relativity and Quantum Cosmology · Physics 2014-11-18 T. Padmanabhan
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