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The purpose of the paper is to study the foundations of the main axioms of Quantum Mechanics. From a general study of the mathematical properties of the models used in Physics to represent systems, we prove that the states of a system can…

Mathematical Physics · Physics 2015-07-02 Jean Claude Dutailly

Loop Quantum Gravity (LQG) is one of the leading approaches to unify quantum physics and General Relativity (GR). The Hilbert space of LQG is spanned by spin-networks which describe the local geometry of quantum space-time. Simulation of…

General Relativity and Quantum Cosmology · Physics 2021-12-21 Swapnil Nitin Shah

Quantum Ricci curvature has been introduced recently as a new, geometric observable characterizing the curvature properties of metric spaces, without the need for a smooth structure. Besides coordinate invariance, its key features are…

High Energy Physics - Theory · Physics 2018-05-30 N. Klitgaard , R. Loll

In the past, the possibility to employ (scalar) material reference systems in order to describe classical and quantum gravity directly in terms of gauge invariant (Dirac) observables has been emphasised frequently. This idea has been picked…

General Relativity and Quantum Cosmology · Physics 2022-12-05 Kristina Giesel , Thomas Thiemann

Loop Quantum Gravity (LQG) is an attempt to describe the quantum gravity regime. Introducing a non-zero cosmological constant $\Lambda$ in this context has been a withstanding problem. Other approaches, such as Chern-Simons gravity, suggest…

General Relativity and Quantum Cosmology · Physics 2013-07-24 Maite Dupuis , Florian Girelli

This is the second paper in the series to introduce a graphical method to loop quantum gravity. We employ the graphical method as a powerful tool to calculate the actions of the Euclidean Hamiltonian constraint operator and the so-called…

General Relativity and Quantum Cosmology · Physics 2016-02-25 Jinsong Yang , Yongge Ma

This research extends quantum singular value transformation (QSVT) for general bounded operators embedded in unitary operators on possibly infinite-dimensional Hilbert spaces. Through in-depth mathematical exploration, we have achieved a…

Quantum Physics · Physics 2024-01-18 Chusei Kiumi , Akito Suzuki

This article presents a simplified version of the author's previous work. We first construct a causal growth process (CGP). We then form path Hilbert spaces using paths of varying lengths in the CGP. A sequence of positive operators on…

Mathematical Physics · Physics 2013-05-23 Stan Gudder

Within a perturbative cosmological regime of loop quantum gravity corrections to effective constraints are computed. This takes into account all inhomogeneous degrees of freedom relevant for scalar metric modes around flat space and results…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Martin Bojowald , Hector Hernandez , Mikhail Kagan , Aureliano Skirzewski

In the previous article a new combinatorial and thus purely algebraical approach to quantum gravity, called Algebraic Quantum Gravity (AQG), was introduced. In the framework of AQG existing semiclassical tools can be applied to operators…

General Relativity and Quantum Cosmology · Physics 2008-11-26 K. Giesel , T. Thiemann

We propose the assumption of quantum mechanics on a discrete space and time, which implies the modification of mathematical expressions for some postulates of quantum mechanics. In particular we have a Hilbert space where the vectors are…

Quantum Physics · Physics 2007-05-23 M. Lorente

In loop quantum gravity, the area element of embedded spatial surfaces is given by a well-defined operator. We further characterize the quantized geometry of such surfaces by proposing definitions for operators quantizing scalar curvature…

General Relativity and Quantum Cosmology · Physics 2018-09-26 David Grüber , Hanno Sahlmann , Thomas Zilker

This paper aims at investigating the influence of space-time curvature on the uncertainty relation. In particular, relying on previous findings, we assume the quantum wave function to be confined to a geodesic ball on a given space-like…

General Relativity and Quantum Cosmology · Physics 2021-06-02 Luciano Petruzziello , Fabian Wagner

Quantum computing is greatly advanced in recent years and is expected to transform the computation paradigm in the near future. Quantum circuit simulation plays a key role in the toolchain for the development of quantum hardware and…

Emerging Technologies · Computer Science 2020-07-21 Yuan-Hung Tsai , Jie-Hong R. Jiang , Chiao-Shan Jhang

This letter is motivated by the recent papers by Dittrich and Thiemann and, respectively, by Rovelli discussing the status of Quantum Geometry in the dynamical sector of Loop Quantum Gravity. Since the papers consider model examples, we…

General Relativity and Quantum Cosmology · Physics 2008-11-07 Wojciech Kaminski , Jerzy Lewandowski , Lukasz Szulc

We introduce a new technique for dealing with the matrix elements of the Hamiltonian operator in loop quantum gravity, based on the use of intertwiners projected on coherent states of angular momentum. We give explicit expressions for the…

General Relativity and Quantum Cosmology · Physics 2016-10-26 Emanuele Alesci , Jerzy Lewandowski , Ilkka Mäkinen

Volume operators measuring the total volume of space in a loop quantum theory of cosmological models are constructed. In the case of models with rotational symmetry an investigation of the Higgs constraint imposed on the reduced connection…

General Relativity and Quantum Cosmology · Physics 2010-11-19 Martin Bojowald

Working within the framework of Loop Quantum Gravity (LQG), we construct a set of three operators suitable for identifying coordinate-like quantities on a spin-network configuration. In doing so, we rely on known properties of operators for…

High Energy Physics - Theory · Physics 2018-07-19 Suddhasattwa Brahma , Antonino Marcianò , Michele Ronco

Quantum reduced loop gravity is designed to consistently study symmetry reduced systems within the loop quantum gravity framework. In particular, it bridges the gap between the effective cosmological models of loop quantum cosmology and the…

General Relativity and Quantum Cosmology · Physics 2018-12-05 Emanuele Alesci , Aurélien Barrau , Gioele Botta , Killian Martineau , Gabriele Stagno

We investigate the Hilbert space in the Lorentz covariant approach to loop quantum gravity. We restrict ourselves to the space where all area operators are simultaneously diagonalizable, assuming that it exists. In this sector quantum…

General Relativity and Quantum Cosmology · Physics 2009-11-07 Sergei Alexandrov