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Taking quantum physics as well as large scale astronomical observations into account, a spacetime metric is introduced, such that the nonlinear part of the Einstein tensor contains effects of the order of Planck's constant.

General Relativity and Quantum Cosmology · Physics 2015-06-25 J. Lamey , G. M. Obermair

A consistent combination of quantum geometry effects rules out a large class of models of loop quantum cosmology and their critical densities as they have been used in the recent literature. In particular, the critical density at which an…

General Relativity and Quantum Cosmology · Physics 2009-03-27 Martin Bojowald

It is argued that the classical local inertial frame used to define rotational states of quantum systems is only approximate, and that geometry itself must also be rotationally quantized at the Planck scale. A Lorentz invariant statistical…

General Relativity and Quantum Cosmology · Physics 2017-06-07 Craig Hogan

Usual quantum mechanics requires a fixed, background, spacetime geometry and its associated causal structure. A generalization of the usual theory may therefore be needed at the Planck scale for quantum theories of gravity in which…

General Relativity and Quantum Cosmology · Physics 2013-12-05 James B. Hartle

A new perspective on the Cosmological Constant Problem (CCP) is proposed and discussed within the multiverse approach of Quantum Cosmology. It is assumed that each member of the ensemble of universes has a characteristic scale $a$ that can…

General Relativity and Quantum Cosmology · Physics 2020-09-09 Vesselin G. Gueorguiev , Andre Maeder

Contextuality is a central property in comparative analysis of classical, quantum, and supercorrelated systems. We examine and compare two well-motivated approaches to contextuality. One approach ("contextuality-by-default") is based on the…

Quantum Physics · Physics 2016-01-21 J. Acacio de Barros , Ehtibar N. Dzhafarov , Janne V. Kujala , Gary Oas

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

We comment on two issues in quantum cosmology, in the context of the Wheeler-De Witt equation and wave function of the Universe: (i) arrow of time and interpretation of the wave function in the classically allowed regions; (ii) stability of…

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

The recent transition from decelerated to accelerated expansion can be seen as a reflection (or "bounce") in the connection variable, defined by the inverse comoving Hubble length ($b=\dot a$, on-shell). We study the quantum cosmology of…

General Relativity and Quantum Cosmology · Physics 2022-10-06 Bruno Alexandre , Joao Magueijo

Heisenberg's intuition was that there should be a tradeoff between measuring a particle's position with greater precision and disturbing its momentum. Recent formulations of this idea have focused on the question of how well two…

Quantum Physics · Physics 2015-07-31 Patrick J. Coles , Fabian Furrer

Phenomenological models are widely used in cosmology in relation to constraining different cosmological models, with two common examples being cosmographic expansions and modeling the equation-of-state parameter of dark energy. This work…

Cosmology and Nongalactic Astrophysics · Physics 2023-08-30 S. M. Koksbang

We consider a scenario where time dependence on physical parameters is introduced by the misalignment of an ultra-light scalar field. The initial VEV of such field at the early time remains a constant until Hubble becomes comparable to its…

High Energy Physics - Phenomenology · Physics 2017-06-07 Yue Zhao

The definition of a length operator in quantum cosmology is usually influenced by a~quantum theory for gravity considered. The semiclassical limit at the Planck age must meet the requirements implied in present observations. The features of…

General Relativity and Quantum Cosmology · Physics 2017-08-29 Orchidea Maria Lecian

We propose a system of equations to describe the interaction of a quasiclassical variable $X$ with a set of quantum variables $x$ that goes beyond the usual mean field approximation. The idea is to regard the quantum system as continuously…

Quantum Physics · Physics 2009-10-30 L. Diosi , J. J. Halliwell

Contextuality is a feature of quantum correlations. It is crucial from a foundational perspective as a nonclassical phenomenon, and from an applied perspective as a resource for quantum advantage. It is commonly defined in terms of hidden…

We consider an object at rest in space with a universal Hubble expansion taking place away from it. We find that a governing differential equation developed from the Schroedinger equation leads to wave functions which turn out to exhibit…

General Physics · Physics 2009-12-08 C. L. Herzenberg

Contextuality is a non-classical behaviour that can be exhibited by quantum systems. It is increasingly studied for its relationship to quantum-over-classical advantages in informatic tasks. To date, it has largely been studied in…

Quantum Physics · Physics 2022-04-20 Rui Soares Barbosa , Tom Douce , Pierre-Emmanuel Emeriau , Elham Kashefi , Shane Mansfield

New Planck scale physics may solve the singularity problems of classical general relativity and may lead to interesting consequences for very early Universe cosmology. Two approaches to these questions are reviewed in this article. The…

General Relativity and Quantum Cosmology · Physics 2016-08-31 Robert H. Brandenberger

As the 2015 results of Plancks mission have recently been made available, it is interesting to check the evolution of the scale factor and of the Hubble parameter in the light of these results. Two models in line with Einsteins field…

General Physics · Physics 2017-06-08 Guibert U. Crevecoeur

Quantum theory does not only predict probabilities, but also relative phases for any experiment, that involves measurements of an ensemble of systems at different moments of time. We argue, that any operational formulation of quantum theory…

Quantum Physics · Physics 2022-10-12 Charis Anastopoulos