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A quantum gravity theory which becomes renormalizable at short distances due to a spontaneous symmetry breaking of Lorentz invariance and diffeomorphism invariance is studied. A breaking of Lorentz invariance with the breaking patterns…

High Energy Physics - Theory · Physics 2010-05-25 J. W. Moffat

A common misconception is that Lorentz invariance is inconsistent with a discrete spacetime structure and a minimal length: under Lorentz contraction, a Planck length ruler would be seen as smaller by a boosted observer. We argue that in…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Etera R. Livine , Daniele Oriti

It has recently been proposed that quantum gravity might lead to the decoherence of superpositions in energy, corresponding to a discretization of time at the Planck scale. At first sight the proposal seems amenable to experimental…

Quantum Physics · Physics 2009-11-10 Christoph Simon , Dieter Jaksch

Recently there have been several studies devoted to the investigation of the fate of fundamental relativistic symmetries at the foreseen unification of gravity and quantum regime, that is the Planck scale. In order to preserve covariance of…

General Relativity and Quantum Cosmology · Physics 2025-02-19 Marco Danilo Claudio Torri

Quantum gravity places entirely new challenges on the formulation of a consistent theory as well as on an extraction of potentially observable effects. Quantum corrections due to the gravitational field are commonly expected to be tiny…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Martin Bojowald

Deformed special relativity is embedded in deformed general relativity using the methods of canonical relativity and loop quantum gravity. Phase-space dependent deformations of symmetry algebras then appear, which in some regimes can be…

General Relativity and Quantum Cosmology · Physics 2013-08-05 Martin Bojowald , George M. Paily

It is argued that the `problem of time' in quantum gravity necessitates a refinement of the local inertial structure of the world, demanding a replacement of the usual Minkowski line element by a 4+2n dimensional pseudo-Euclidean line…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Joy Christian

The semiclassical gravity describes gravitational back-reactions of the classical spacetime interacting with quantum matter fields but the quantum effects on the background is formally defined as higher derivative curvatures. These induce…

General Relativity and Quantum Cosmology · Physics 2020-02-06 Hiroki Matsui , Naoki Watamura

In recent years several ideas for experimental searches of effects induced by quantum properties of space-time have been discussed. Some of these ideas concern the role in quantum spacetime of the ordinary Lorentz symmetry of classical flat…

Astrophysics · Physics 2007-05-23 Giovanni Amelino-Camelia

We investigate the effects of Quantum Gravity on the Planck era of the universe. In particular, using different versions of the Generalized Uncertainty Principle and under specific conditions we find that the main Planck quantities such as…

High Energy Physics - Theory · Physics 2010-09-28 Spyros Basilakos , Saurya Das , Elias C. Vagenas

We calculate deviations in cosmological observables as a function of parameters in a class of connection-based models of quantum gravity. In this theory non-trivial modifications to the background cosmology can occur due to a distortion of…

Cosmology and Nongalactic Astrophysics · Physics 2023-02-01 Michael W. Toomey , Savvas Koushiappas , Bruno Alexandre , João Magueijo

There are several theoretical indications that the quantum gravity approaches may have predictions for a minimal measurable length, and a maximal observable momentum and throughout a generalization for Heisenberg uncertainty principle. The…

General Physics · Physics 2015-12-22 Abdel Nasser Tawfik , H. Magdy , A. Farag Ali

We describe a deformation of the observable algebra of quantum gravity in which the loop algebra is extended to framed loops. This allows an alternative nonperturbative quantization which is suitable for describing a phase of quantum…

General Relativity and Quantum Cosmology · Physics 2009-09-25 Seth Major , Lee Smolin

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

We argue that a (slightly) curved space-time probed with a finite resolution, equivalently a finite minimal length, is effectively described by a flat non-commutative space-time. More precisely, a small cosmological constant (so a constant…

General Relativity and Quantum Cosmology · Physics 2016-08-31 Florian Girelli , Etera R. Livine , Daniele Oriti

The modification of the quantum mechanical commutators in a relativistic theory with an invariant length scale (DSR) is identified. Two examples are discussed where a classical behavior is approached in one case when the energy approaches…

High Energy Physics - Theory · Physics 2009-11-10 J. L. Cortes , J. Gamboa

We present a simple algebraic argument for the conclusion that the low energy limit of a quantum theory of gravity must be a theory invariant, not under the Poincare group, but under a deformation of it parameterized by a dimensional…

High Energy Physics - Theory · Physics 2009-11-10 Giovanni Amelino-Camelia , Lee Smolin , Artem Starodubtsev

Using the Cartan formulation of General Relativity, we construct a well defined lattice-regularized theory capable to describe large non-perturbative quantum fluctuations of the frame field (or the metric) and of the spin connection. To…

High Energy Physics - Theory · Physics 2011-09-02 Dmitri Diakonov

We use results by Kirilin to show that in general relativity the nonleading terms in the energy-momentum tensor of a particle depends on the parameterization of the gravitational field. While the classical metric that is calculated from…

General Relativity and Quantum Cosmology · Physics 2008-11-26 N. E. J. Bjerrum-Bohr , John F. Donoghue , Barry R. Holstein

A new approach to Quantum Gravity is proposed that is manifestly compatible with Cellular Automata (CA) theory, and is based on a new quantum theory of inertia where Newtonian Inertia results from the electromagnetic forces between the…

General Physics · Physics 2007-05-23 Tom Ostoma , Mike Trushyk