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In cosmology, the cosmic curvature $K$ and the cosmological constant $\Lambda$ are two important parameters, and the values have strong influence on the behavior of the universe. In the context of normal cosmology, under the ordinary…

General Relativity and Quantum Cosmology · Physics 2017-08-11 Ying-Qiu Gu

This paper continues the development of a discrete space-time concept that is recently used in the explanation of the cosmological constant. Instead of order estimation, a more theoretical treatment of the theory is introduced. Based on the…

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

In a recent article we showed that the analog of the cosmological constant in two spacetime dimensions for a wide variety of integrable quantum field theories has the form $\rho_{\rm vac} = - m^2 /2 \mathfrak{g} $ where $m$ is a physical…

High Energy Physics - Theory · Physics 2025-09-15 André LeClair

We discuss the possibility of a dynamical solution to the cosmological constant problem in the contaxt of six-dimensional Einstein-Maxwell theory. A definite answer requires an understanding of the full bulk cosmology in the early universe,…

High Energy Physics - Theory · Physics 2009-11-11 Jan-Markus Schwindt , Christof Wetterich

The cosmological constant, i.e., the energy density stored in the true vacuum state of all existing fields in the Universe, is the simplest and the most natural possibility to describe the current cosmic acceleration. However, despite its…

Astrophysics · Physics 2008-11-26 S. Carneiro , M. A. Dantas , C. Pigozzo , J. S. Alcaniz

A two dimensional matter coupled model of quantum gravity is studied in the Dirac approach to constrained dynamics in the presence of a cosmological constant. It is shown that after partial fixing to the conformal gauge the requirement of a…

High Energy Physics - Theory · Physics 2011-08-29 Jan Govaerts , Simone Zonetti

If the observed dark energy is a cosmological constant, the canonical state of the universe is de Sitter spacetime. In such a spacetime, quantum fluctuations that violate the null energy condition will create islands of matter that, if…

General Relativity and Quantum Cosmology · Physics 2009-04-30 Sourish Dutta , Tanmay Vachaspati

In this paper we continue the investigations in \cite{1} concerning the origin of the cosmological constant. First of all, we generalise the results in \cite{1,2} by considering a continuum approximation for a radiation field in a…

General Relativity and Quantum Cosmology · Physics 2019-08-23 Stefano Viaggiu

The present paper seeks to construct a quantum theory of the cosmological constant in which its presently observed very small value emerges naturally.

General Relativity and Quantum Cosmology · Physics 2007-06-13 Budh Ram

There are now two cosmological constant problems: (i) why the vacuum energy is so small and (ii) why it comes to dominate at about the epoch of galaxy formation. Anthropic selection appears to be the only approach that can naturally resolve…

High Energy Physics - Theory · Physics 2007-06-20 Alexander Vilenkin

A range of cosmological observations demonstrate an accelerated expansion of the Universe, and the most likely explanation of this phenomenon is a cosmological constant. Given the importance of understanding the underlying physics, it is…

Cosmology and Nongalactic Astrophysics · Physics 2021-04-07 Karoline Loeve , Kristine Simone Nielsen , Steen H. Hansen

It has recently been proposed [M. P. Hertzberg and A. Loeb, arXiv:2302.09090] that the observed value of the cosmological constant can be related to the physical parameters of the Standard Model. In the present compact note we point out…

General Relativity and Quantum Cosmology · Physics 2023-02-23 Shahar Hod

Within conventional big bang cosmology, it has proven to be very difficult to understand why today's cosmological constant is so small. In this paper, we show that a cyclic model of the universe can naturally incorporate a dynamical…

Astrophysics · Physics 2009-09-01 Paul J. Steinhardt , Neil Turok

Two sides of cosmological constant problem are discussed: a mysterious compensation of all contributions to vacuum energy with the accuracy of 100-50 orders of magnitude and a surprising equality of a constant vacuum energy density to the…

High Energy Physics - Phenomenology · Physics 2007-05-23 A. D. Dolgov

We present a simple quantum-mechanical estimate of the cosmological constant of a Newtonian Universe. We first mimic the dynamics of a Newtonian spacetime by means of a nonrelativistic quantum mechanics for the matter contents of the…

General Relativity and Quantum Cosmology · Physics 2020-12-02 J. C. Castro-Palacio , P. Fernandez de Cordoba , J. M. Isidro

The evolution of the wave function in quantum mechanics is deterministic like that of classical waves. Only when we bring in observers the fundamentally different quantum reality emerges. Similarly the introduction of observers changes the…

General Physics · Physics 2020-10-16 Jan O. Stenflo

Well tempering is one of the few classical field theory methods for solving the original cosmological constant problem, dynamically canceling a large (possibly Planck scale) vacuum energy and leaving the matter component intact, while…

Cosmology and Nongalactic Astrophysics · Physics 2021-01-15 Stephen Appleby , Eric V. Linder

This article aims at discussing the cosmological constant problem at a pedagogical but fully technical level. We review how the vacuum energy can be regularized in flat and curved space-time and how it can be understood in terms of Feynman…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 Jerome Martin

The idea of the quantum state of the Universe described by some density matrix, i.e mixture of at least two vacua, the trivial symmetric and the nontrivial one with spontaneously broken symmetry is discussed. Nonzero cosmological constant…

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

It is suggested that the exact value of the cosmological constant could be derived from first principles, based on entanglement of the Standard Model field vacuum with emergent holographic quantum geometry. For the observed value of the…

General Relativity and Quantum Cosmology · Physics 2018-04-03 Craig Hogan