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Related papers: Dark energy from quantum gravity discreteness

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Based on the work of ratio gravity developed in 2018, which postulates the deformation of the cross ratio to associate with the physical model of gravity, we develop a mechanism to generate dynamical dark energy - a quintessence field…

General Relativity and Quantum Cosmology · Physics 2022-02-25 Jackie C. H. Liu

Quantum gravity effects are traditionally tied to short distances and high energies. In this essay we argue that, perhaps surprisingly, quantum gravity may have important consequences for the phenomenology of the infrared. We center our…

General Relativity and Quantum Cosmology · Physics 2022-05-19 Laurent Freidel , Jerzy Kowalski-Glikman , Robert G. Leigh , Djordje Minic

We consider here the possibility of quantum gravity induced violation of Lorentz symmetry (LV). Even if suppressed by the inverse Planck mass such LV can be tested by current experiments and astrophysical observations. We review the…

Astrophysics · Physics 2008-11-26 Ted Jacobson , Stefano Liberati , David Mattingly

In this work we study a scale invariant gravity theory containing two scalar fields, dust particles and a measure defined from degrees of freedom independent of the metric. The integration of the degrees of freedom that define the measure…

General Relativity and Quantum Cosmology · Physics 2026-05-21 Eduardo I. Guendelman , Ramon Herrera , Pedro Labrana

The concept of exotic charged dust is introduced here to represent dark matter. The term "exotic" means that the dust is not composed of normal matter, and the charge--for lack of a better term--is not an electric charge. It is also shown…

General Physics · Physics 2025-04-23 Gerald E. Marsh

The distinction between modified gravity and quintessence or dynamical dark energy is difficult. Many models of modified gravity are equivalent to models of coupled quintessence by virtue of variable transformations. This makes an…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-18 C. Wetterich

Within the thermodynamic model of gravity the dark energy is identified with the energy of collective gravitational interactions of all particles in the universe, which is missing in the standard treatments. For the model-universe we…

General Relativity and Quantum Cosmology · Physics 2014-12-01 Merab Gogberashvili

In this dissertation, the nature of Dark Energy (DE) is examined from both theoretical and phenomenological perspectives. The possibility of DE being a dynamic quantity in quantum field theory (QFT) in curved spacetime is studied. The…

General Relativity and Quantum Cosmology · Physics 2023-11-14 Cristian Moreno-Pulido

Canonical quantum gravity provides insights into the quantum dynamics as well as quantum geometry of space-time by its implications for constraints. Loop quantum gravity in particular requires specific corrections due to its quantization…

General Relativity and Quantum Cosmology · Physics 2015-05-14 Martin Bojowald

In the following we undertake to derive quantum theory as a stochastic low-energy and coarse-grained theory from a more primordial discrete and basically geometric theory living on the Planck scale and which (as we argue) possibly underlies…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Manfred Requardt

Quantum gravitational effects suggest a minimal length, or spacetime interval, of order the Planck length. This in turn suggests that Hilbert space itself may be discrete rather than continuous. One implication is that quantum states with…

General Relativity and Quantum Cosmology · Physics 2021-02-24 Stephen D. H. Hsu

We study the possibility to constrain deviations from Lorentz invariance in dark matter (DM) with cosmological observations. Breaking of Lorentz invariance generically introduces new light gravitational degrees of freedom, which we…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 Diego Blas , Mikhail M. Ivanov , Sergey Sibiryakov

We review a novel and authentic way to quantize gravity. This novel approach is based on the fact that Einstein gravity can be formulated in terms of a symplectic geometry rather than a Riemannian geometry in the context of emergent…

High Energy Physics - Theory · Physics 2014-12-30 Jungjai Lee , Hyun Seok Yang

Dynamical vacuum energy or quintessence, a slowly varying and spatially inhomogeneous component of the energy density with negative pressure, is currently consistent with the observational data. One potential difficulty with the idea of…

General Relativity and Quantum Cosmology · Physics 2014-11-17 Takeshi Chiba

The paper aims to provide an explanation for the tiny value of the cosmological constant and the low vacuum energy density to represent the dark energy. To accomplish this, we will search for a fundamental principle of symmetry in…

General Relativity and Quantum Cosmology · Physics 2016-11-14 Cláudio Nassif

The work shows that the associated Einstein like gravity for the Klein-Gordon field shows the spontaneous emergence of the cosmological pressure tensor density (CPTD) that in the classical limit leads to the cosmological constant (CC). Even…

General Physics · Physics 2020-07-07 Piero Chiarelli

We investigate the problem of metric fluctuations in the presence of the vacuum fluctuations of matter fields and critically assess the usual assertion that vacuum energy implies a Planckian cosmological constant. A new stochastic classical…

General Relativity and Quantum Cosmology · Physics 2008-06-19 Charles H. -T. Wang , Paolo M. Bonifacio , Robert Bingham , J. Tito Mendonca

Quantum Gravity framework motivates us to find new theories in which an observer independent finite energy upper bound (preferably Planck Energy) exists. We have studied the modifications in the thermodynamical properties of a photon gas in…

High Energy Physics - Theory · Physics 2010-05-12 Sudipta Das , Dibakar Roychowdhury

The Einstein equation in a semi-classical approximation is applied to a spherical region of the universe, with the stress-energy tensor consisting of the mass density and pressure of the LambdaCDM cosmological model plus an additional…

General Relativity and Quantum Cosmology · Physics 2024-12-11 Emilio Santos

Einstein's theory of gravity admits a low energy effective quantum field description from which predictions beyond classical general relativity can be drawn. As gravitational wave detectors improve, one may ask whether non-classical…

General Relativity and Quantum Cosmology · Physics 2023-06-19 Thiago Guerreiro