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In the presence of the gravitational field, the energy density of matter no longer coincides with its mass density. A discrepancy exists, of course, also between the associated power spectra. Within the $\Lambda$CDM model, we derive a…

General Relativity and Quantum Cosmology · Physics 2024-04-08 Maxim Eingorn , Ezgi Yilmaz , A. Emrah Yükselci , Alexander Zhuk

A new vision of the beginning and expansion of our universe has produced a solution to the vacuum energy problem (also known as "cosmological constant problem"). A new dynamic of cellular spaces and a discrete time has space being produced…

Astrophysics · Physics 2007-05-23 Charles B. Leffert

One hope to solve the cosmological constant problem is to identify a symmetry principle, based on which the cosmological constant can be reduced either to zero, or to a tiny value. Here, we note that requiring that the vacuum state is…

General Relativity and Quantum Cosmology · Physics 2011-06-01 Jurjen F. Koksma , Tomislav Prokopec

A huge discrepancy between the zero-point energy calculated from quantum theory and the observed quantity in the Universe has been one of the most illusive problems in physics. In order to examine the measurability of zero-point energy, we…

Quantum Physics · Physics 2008-03-21 Daegene Song

The possibility that the vacuum energy density (VED), $\rho_{\rm vac}$, could be time dependent in the expanding Universe is intuitively more reasonable than just a rigid cosmological constant for the entire cosmic history. The dynamics of…

General Relativity and Quantum Cosmology · Physics 2024-04-29 Joan Solà Peracaula

We propose a new approach to understand hierarchy problem for cosmological constant in terms of considering noncommutative nature of space-time. We calculate that vacuum energy density of the noncommutative quantum field theories in…

High Energy Physics - Theory · Physics 2007-05-23 Xiao-Jun Wang

We explicitly compute the dynamics of closed homogeneous and isotropic universes permeated by a single perfect fluid with a constant equation of state parameter $w$ in the context of a recent reformulation of general relativity, proposed in…

General Relativity and Quantum Cosmology · Physics 2015-05-06 P. P. Avelino

Any canonical quantum theory can be understood to arise from the compatibility of the statistical geometry of distinguishable observations with the canonical Poisson structure of Hamiltonian dynamics. This geometric perspective offers a…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Vishnu Jejjala , Djordje Minic , Chia-Hsiung Tze

It is suggested that the vacuum expectation of the quantum vacuum energy-momentum is zero, but quantum fluctuations give rise to a space-time curvature equivalent to that of a cosmological constant or dark energy. Calculations within…

General Relativity and Quantum Cosmology · Physics 2009-02-26 Emilio Santos

We advance the viewpoint that only relevant modes of the vacuum fluctuations, namely, with wavelengths conditioned by the size, homogeneity, geometry and topology of the Universe, do contribute into the cosmological constant. A formula is…

Astrophysics · Physics 2014-10-13 V. G. Gurzadyan , She-Sheng Xue

The equations of motion describing all physical systems, except gravity, remain invariant if a constant is added to the Lagrangian. In the conventional approach, gravitational theories break this symmetry exhibited by all other physical…

General Relativity and Quantum Cosmology · Physics 2015-12-22 T. Padmanabhan

In this letter we address some of the issues raised in the literature about the conflict between a large vacuum energy density, apriori predicted by quantum field theory, and the observed dark energy which must be the energy of vacuum or…

High Energy Physics - Theory · Physics 2012-08-08 Houri Ziaeepour

Within the $\Lambda$CDM cosmological model, the absolute value of Einstein's cosmological constant $\Lambda$, sometimes expressed as the gravitating mass-energy density $\rho_\Lambda$ of the physical vacuum, is a fundamental constant of…

Cosmology and Nongalactic Astrophysics · Physics 2022-06-22 J. Prat , C. Hogan , C. Chang , J. Frieman

The macroscopic behavior of many physical systems can be approximately described by classical quantities. However, quantum theory demands the existence of omnipresent quantum fluctuations on top of this classical background -- which, albeit…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Ralf Schützhold

We consider general theoretical models of water and in particular the nature of the motions of the hydrogen nuclei. If the motion of hydrogen nuclei is classical, then the thermodynamic pressure equation of state for heavy water wherein the…

Other Condensed Matter · Physics 2015-12-11 A. Widom , J. Swain , S. Sivasubramanian , D. Drosdoff , Y. N. Srivastava

An analogy between non-relativistic quantum mechanics in the Madelung formulation and quantum geometrodynamics in the case of the maximally symmetric space is drawn. The equations equivalent to the continuity equation and the hydrodynamic…

General Relativity and Quantum Cosmology · Physics 2025-07-29 V. E. Kuzmichev , V. V. Kuzmichev

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

In this work the Vacuum Energy Density Problem or Dark Energy Problem is studied on the basis of the earlier results by the author within the scope of the Holographic Principle. It is demonstrated that the previously introduced deformed…

High Energy Physics - Theory · Physics 2007-05-23 A. E. Shalyt-Margolin

Is the hydrodynamics of an interacting many-body system fundamentally limited by basic principles of quantum mechanics? Starting with the conjecture that viscosity is at least as large as entropy density (as measured in fundamental units),…

High Energy Physics - Theory · Physics 2017-10-27 Andrew Lucas

Gravitational holography is argued to render the cosmological constant stable against divergent quantum corrections. This provides a technically natural solution to the cosmological constant problem. Evidence for quantum stability of the…

High Energy Physics - Theory · Physics 2007-05-23 Scott Thomas
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