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In this manuscript, we will discuss the construction of covariant derivative operator in quantum gravity. We will find it is more perceptive to use affine connections more general than metric compatible connections in quantum gravity. We…

General Physics · Physics 2019-04-30 Kaushik Ghosh

The adiabatic theorem states that when the time evolution of the Hamiltonian is "infinitely slow", a system, when started in the ground state, remains in the instantaneous ground state at all times. This, however, does not mean that the…

Quantum Physics · Physics 2025-05-09 Raffaele Resta

I analyze the deformation of Lorentz symmetry that holds in certain noncommutative spacetimes and the way in which Lorentz symmetry is broken in other noncommutative spacetimes. I also observe that discretization of areas does not…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Giovanni Amelino-Camelia

This article is an extended version of the peer-reviewed publication; Moffat and Wang, J Phys Math 2018, 9:4 DOI: 10.4172/2090-0902.1000289 The article sets out to address a number of issues concerning Loop Quantum Gravity raised by…

General Physics · Physics 2019-03-12 James Moffat , Charles H-T Wang

We show that the quantization ambiguities of loop quantum cosmology, when considered in wider generality, can be used to produce discretionary dynamical behavior. There is an infinite dimensional space of ambiguities which parallels the…

General Relativity and Quantum Cosmology · Physics 2023-05-03 Lautaro Amadei , Alejandro Perez , Salvatore Ribisi

The possible role of gravity in a noncommutative geometry is investigated. Due to the Moyal *-product of fields in noncommutative geometry, it is necessary to complexify the metric tensor of gravity. We first consider the possibility of a…

High Energy Physics - Theory · Physics 2009-10-31 J. W. Moffat

In several approaches towards a quantum theory of gravity, such as group field theory and loop quantum gravity, quantum states and histories of the geometric degrees of freedom turn out to be based on discrete spacetime. The most pressing…

General Relativity and Quantum Cosmology · Physics 2018-08-01 Johannes Thürigen

We use a recent formalism of quantum geodesics in noncommutative geometry to construct geodesic flow on the infinite chain $\cdots\bullet$--$\bullet$--$\bullet\cdots$. We find that noncommutative effects due to the discretisation of the…

Quantum Algebra · Mathematics 2023-09-27 Edwin Beggs , Shahn Majid

Relativistic Quantum Mechanics suffers from structural problems which are traced back to the lack of a position operator $\hat{x}$, satisfying $[\hat{x},\hat{p}]=i\hbar\hat{1}$ with the ordinary momentum operator $\hat{p}$, in the basic…

High Energy Physics - Theory · Physics 2009-10-28 V. Aldaya , J. Guerrero

The classical Hilbert space formulation of the axioms of Quantum Mechanics appears to leave open the question whether the Hermitian operators which are associated with the observables of a finite non-relativistic quantum system are uniquely…

Quantum Physics · Physics 2007-05-23 E. E. Rosinger

Local observables in (perturbative) quantum gravity are notoriously hard to define, since the gauge symmetry of gravity -- diffeomorphisms -- moves points on the manifold. In particular, this is a problem for backgrounds of high symmetry…

General Relativity and Quantum Cosmology · Physics 2023-11-14 Markus B. Fröb , Albert Much , Kyriakos Papadopoulos

In a remarkable paper, T. Koslowski introduced kinematical representations for loop quantum gravity in which there is a non-degenerate spatial background metric present. He also considered their properties, and showed that Gauss and…

General Relativity and Quantum Cosmology · Physics 2010-10-27 Hanno Sahlmann

We study the holographic properties of a class of quantum geometry states characterized by a superposition of discrete geometric data, in the form of generalised tensor networks. This class specifically includes spin networks, the kinematic…

Quantum Physics · Physics 2024-02-28 Eugenia Colafranceschi , Simon Langenscheidt , Daniele Oriti

The mathematical structure of homogeneous loop quantum cosmology is analyzed, starting with and taking into account the general classification of homogeneous connections not restricted to be Abelian. As a first consequence, it is seen that…

General Relativity and Quantum Cosmology · Physics 2013-12-31 Martin Bojowald

A quantum-mechanical system comes naturally equipped with a convex space: each (Hermitian) operator has a (real) expectation value, and the expectation value of the square any Hermitian operator must be non-negative. This space is of…

High Energy Physics - Lattice · Physics 2025-02-05 Scott Lawrence

Gazeau-Klauder coherent states in noncommutative quantum mechanics are considered. We find that these states share similar properties to those of ordinary canonical coherent states in the sense that they saturate the related position…

High Energy Physics - Theory · Physics 2015-05-13 J Ben Geloun , F G Scholtz

Several conceptual aspects of quantum gravity are studied on the example of the homogeneous isotropic LQC model. In particular: $(i)$ The proper time of the co-moving observers is showed to be a quantum operator {and} a quantum spacetime…

General Relativity and Quantum Cosmology · Physics 2009-01-27 Wojciech Kaminski , Jerzy Lewandowski , Tomasz Pawlowski

In this paper a nonlocal generalization of field quantization is suggested. This quantization principle presupposes the assumption that the commutator between a field operator an the operator of the canonical conjugated variable referring…

General Physics · Physics 2016-09-02 Martin Kober

We study the quantum fermions+gravity system, that is, the gravitational counterpart of QED. We start from the standard Einstein-Weyl theory, reformulated in terms of Ashtekar variables; and we construct its non- perturbative quantum theory…

General Relativity and Quantum Cosmology · Physics 2009-10-22 H A Marales-Tecotl , C Rovelli

Deformations of the canonical commutation relations lead to non-Hermitian momentum and position operators and therefore almost inevitably to non-Hermitian Hamiltonians. We demonstrate that such type of deformed quantum mechanical systems…

High Energy Physics - Theory · Physics 2014-11-20 Bijan Bagchi , Andreas Fring
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