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We present a broad and simple class of scalar-tensor scenarios that successfully realize dynamical damping of the effective cosmological constant, therefore providing a viable dynamical solution to the fine-tuning or "old" cosmological…

General Relativity and Quantum Cosmology · Physics 2018-12-27 Oleg Evnin , Kévin Nguyen

It will be argued here that the cosmological constant problem exists because of the way the vacuum is defined in quantum field theory. It has been known for some time that for QFT to be gauge invariant certain terms--such as part of the…

General Relativity and Quantum Cosmology · Physics 2008-06-20 Gerald E. Marsh

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 non-commutative multi-dimensional cosmological model is introduced and used to address the issues of compactification and stabilization of extra dimensions and the cosmological constant problem. We show that in such a scenario these…

High Energy Physics - Theory · Physics 2009-11-11 N. Khosravi , S. Jalalzadeh , H. R. Sepangi

We show how the scalar field, a candidate of quintessence, in a proposed model of the scalar-tensor theories of gravity provides a way to understand a small but nonzero cosmological constant as indicated by recent observations. A particular…

General Relativity and Quantum Cosmology · Physics 2009-09-25 Yasunori Fujii

The typical scalar field theory has a cosmological constant problem. We propose a generic mechanism by which this problem is avoided at tree level by embedding the theory into a larger theory. The metric and the scalar field coupling…

High Energy Physics - Phenomenology · Physics 2012-07-11 Roman V. Buniy , Thomas W. Kephart

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

The cosmological constant problem can be understood as the failure of the decoupling principle behind effective field theory, so that some quantities in the low-energy theory are extremely sensitive to the high-energy properties. While this…

High Energy Physics - Theory · Physics 2015-12-01 Carlos Barceló , Raúl Carballo-Rubio , Luis J. Garay

We consider a dynamical approach to the cosmological constant. There is a scalar field with a potential whose minimum occurs at a generic, but negative, value for the vacuum energy, and it has a non-standard kinetic term whose coefficient…

High Energy Physics - Theory · Physics 2016-09-06 Shinji Mukohyama , Lisa Randall

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

Recent cosmological observations suggest the existence of a positive cosmological constant $\Lambda$ with the magnitude $\Lambda(G\hbar/c^3) \approx 10^{-123}$. This review discusses several aspects of the cosmological constant both from…

High Energy Physics - Theory · Physics 2008-11-26 T. Padmanabhan

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

We have recently presented a manifestly local and general coordinate invariant formulation of a nonlocal approach to the cosmological constant problem which has been proposed by Carroll and Remmen. In this article, based on our formulation,…

High Energy Physics - Theory · Physics 2017-07-26 Ichiro Oda

After a brief outlook of the dynamic quantization method and application of the method to gravity the idea of natural solution of cosmological constant problem in inflating Universe is presented.

High Energy Physics - Theory · Physics 2016-09-06 S. N. Vergeles

We extend the usual gravitational action principle by promoting the bare cosmological constant (CC) from a parameter to a field which can take many possible values. Variation leads to a new integral constraint equation which determines the…

General Relativity and Quantum Cosmology · Physics 2011-03-21 John D. Barrow , Douglas J. Shaw

Quantum theory, general relativity, the standard model of particle physics, and the $\Lambda$CDM model of cosmology have all been spectacularly successful within their respective regimes of applicability, but many central problems remain…

General Physics · Physics 2026-05-26 Roland E. Allen

We consider cosmological model in 4+1 dimensions with variable scale factor in extra dimension and static external space. The time scale factor is changing. Variations of light velocity, gravity constant, mass and pressure are determined…

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

These notes present a brief introduction to `naturalness' problems in cosmology, and to the Cosmological Constant Problem in particular. The main focus is the `old' cosmological constant problem, though the more recent variants are also…

High Energy Physics - Theory · Physics 2013-09-18 C. P. Burgess

We introduce a dynamical model to reduce a large cosmological constant to a sufficiently small value. The basic ingredient in this model is a distinction which has been made between the two unit systems used in cosmology and particle…

General Relativity and Quantum Cosmology · Physics 2010-05-12 Yousef Bisabr

We present here a note which synthesizes our previous ideas concerning some problems in cosmology, and the numerical correspondences between the physical constants that we could deduce.

General Physics · Physics 2008-02-06 Christophe Real