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In a recent paper (arXiv:1412.6000) a general mechanism for emergence of cosmological space-time geometry from a quantum gravity setting was devised and departure from standard dispersion relations for elementary particle were predicted. We…

General Relativity and Quantum Cosmology · Physics 2015-12-16 Ricardo Gallego Torromé , Marco Letizia , Stefano Liberati

A longstanding question in quantum gravity regards the localization of quantum information; one way to formulate this question is to ask how subsystems can be defined in quantum-gravitational systems. The gauge symmetry and necessity of…

High Energy Physics - Theory · Physics 2022-09-07 Steven B. Giddings

In this paper we present exactly solved extended quintessence models; furthermore, through a dynamical effective Q-cosmological "constant", we recover some of the L decaying cases found in the literature. Finally we introduce a sort of…

Astrophysics · Physics 2008-11-26 R. de Ritis , A. A. Marino

A crucial problem in quantum cosmology is a careful analysis of the one-loop semiclassical approximation for the wave function of the universe, after an appropriate choice of mixed boundary conditions. The results for Euclidean quantum…

High Energy Physics - Theory · Physics 2007-05-23 Giampiero Esposito , Alexander Yu. Kamenshchik

We describe our recent proposal of a path integral formulation of classical Hamiltonian dynamics. Which leads us here to a new attempt at hybrid dynamics, which concerns the direct coupling of classical and quantum mechanical degrees of…

Quantum Physics · Physics 2011-07-11 H-T Elze , G Gambarotta , F Vallone

The anomalous dimensions of the Planck mass and the cosmological constant are calculated in a renormalizable quantum conformal gravity with a single dimensionless coupling, which is formulated using dimensional regularization on the basis…

High Energy Physics - Theory · Physics 2016-04-11 Ken-ji Hamada , Mikoto Matsuda

After a brief introduction to classical and quantum gravity we discuss applications of loop quantum gravity in the cosmological realm. This includes the basic formalism and recent results of loop quantum cosmology, and a computation of…

General Relativity and Quantum Cosmology · Physics 2017-08-23 Martin Bojowald , Hugo A. Morales-Tecotl

The graphical calculus method is generalized to study the relation between covariant and canonical dynamics of loop quantum gravity. On one hand, a graphical derivation of the partition function of the generalized Euclidean…

General Relativity and Quantum Cosmology · Physics 2021-08-17 Jinsong Yang , Cong Zhang , Yongge Ma

To understand the dynamics of loop quantum gravity, the deparametrized model of gravity coupled to a scalar field is studied in a simple case, where the graph underlying the spin network basis is one loop based at a single vertex. The…

General Relativity and Quantum Cosmology · Physics 2019-06-20 Cong Zhang , Jerzy Lewandowski , Haida Li , Yongge Ma

It is argued that the so-called holographic principle will obstruct attempts to produce physically realistic models for the unification of general relativity with quantum mechanics, unless determinism in the latter is restored. The notion…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Gerard 't Hooft

It has been known for some time that the cosmological Friedmann equation deduced from General Relativity can be also obtained within the Newtonian framework under certain assumptions. We use this result together with quantum corrections to…

General Relativity and Quantum Cosmology · Physics 2016-11-03 Pedro Bargueño , Sergio Bravo-Medina , Marek Nowakowski , Davide Batic

A non-perturbative quantum field theory of General Relativity is presented which leads to a new realization of the theory of Covariant Quantum-Gravity (CQG-theory). The treatment is founded on the recently-identified Hamiltonian structure…

General Relativity and Quantum Cosmology · Physics 2017-05-24 Claudio Cremaschini , Massimo Tessarotto

A recently proposed version of mimetic gravity incorporates a limiting curvature into general relativity by means of a specific potential depending on the d'Alembertian of the scalar field. In the homogeneous and isotropic setting, the…

General Relativity and Quantum Cosmology · Physics 2019-10-28 Norbert Bodendorfer , Fabio M. Mele , Johannes Münch

The correct implementation of the Loop Quantum Gravity to the early homogeneous Universe has been the subject of a long debate in the literature because the SU(2) symmetry cannot be properly retained. The role of this symmetry is expressed…

General Relativity and Quantum Cosmology · Physics 2023-08-16 Matteo Bruno , Giovanni Montani

The problem of finding the quantum theory of the gravitational field, and thus understanding what is quantum spacetime, is still open. One of the most active of the current approaches is loop quantum gravity. Loop quantum gravity is a…

General Relativity and Quantum Cosmology · Physics 2016-10-19 Carlo Rovelli

In quantum gravity perturbation theory in Newton's constant G is known to be badly divergent, and as a result not very useful. Nevertheless some of the most interesting phenomena in physics are often associated with non-analytic behavior in…

High Energy Physics - Theory · Physics 2019-03-19 Herbert W. Hamber

We review some recent attempts to extract information about the nature of quantum gravity, with and without matter, by quantum field theoretical methods. More specifically, we work within a covariant lattice approach where the individual…

High Energy Physics - Theory · Physics 2007-05-23 J. Ambjorn , J. Jurkiewicz , R. Loll

Homogeneous cosmological models with non-vanishing intrinsic curvature require a special treatment when they are quantized with loop quantum cosmological methods. Guidance from the full theory which is lost in this context can be replaced…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Martin Bojowald , Ghanashyam Date , Kevin Vandersloot

We present a critical analysis of the Canonical approach to quantum gravity, which relies on the ambiguity of implementing a space-time slicing on the quantum level. We emphasize that such a splitting procedure is consistent only if a real…

General Relativity and Quantum Cosmology · Physics 2016-11-15 Giovanni Montani

This introductory review is addressed to beginning researchers. Some of the distinguishing features of loop quantum gravity are illustrated through loop quantum cosmology of FRW models. In particular, these examples illustrate: i) how…

General Relativity and Quantum Cosmology · Physics 2010-11-11 Abhay Ashtekar
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