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We analyze the spectral properties of the volume operator of Ashtekar and Lewandowski in Loop Quantum Gravity, which is the quantum analogue of the classical volume expression for regions in three dimensional Riemannian space. Our analysis…

General Relativity and Quantum Cosmology · Physics 2010-11-22 Johannes Brunnemann , David Rideout

Several proposals for Quantum Gravity involve length and area operators with discrete eigenvalues. I show that the analyses of some simple procedures for the measurement of areas and lengths suggest that this discreteness characterizing the…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Giovanni Amelino-Camelia

Starting from a real scalar quantum field theory with quartic self-interactions and non-minimal coupling to classical gravity, we define four equal-time, spatially covariant phase-space operators through a Wigner transformation of spatially…

General Relativity and Quantum Cosmology · Physics 2018-07-17 Pavel Friedrich , Tomislav Prokopec

We construct in this article a new realization of quantum geometry, which is obtained by quantizing the recently-introduced flux formulation of loop quantum gravity. In this framework, the vacuum is peaked on flat connections, and states…

General Relativity and Quantum Cosmology · Physics 2021-06-18 Benjamin Bahr , Bianca Dittrich , Marc Geiller

The discrete picture of geometry arising from the loop representation of quantum gravity can be extended by a quantum deformation. The operators for area and volume defined in the q-deformation of the theory are partly diagonalized. The…

General Relativity and Quantum Cosmology · Physics 2009-10-28 Roumen Borissov , Seth Major , Lee Smolin

We summarize a recently proposed concrete programme for investigating the (semi)classical limit of canonical, Lorentzian, continuum quantum general relativity in four spacetime dimensions. The analysis is based on a novel set of coherent…

General Relativity and Quantum Cosmology · Physics 2009-11-07 H. Sahlmann , T. Thiemann , O. Winkler

We analyze the classical limit of kinematic loop quantum gravity in which the diffeomorphism and hamiltonian constraints are ignored. We show that there are no quantum states in which the primary variables of the loop approach, namely the…

General Relativity and Quantum Cosmology · Physics 2014-11-17 Madhavan Varadarajan , José A. Zapata

We construct the regularised Wheeler-De Witt operator demanding that the algebra of constraints of quantum gravity is anomaly free. We find that for a subset of all wavefunctions being integrals of scalar densities this condition can be…

General Relativity and Quantum Cosmology · Physics 2016-08-15 A. Błaut , J. Kowalski-Glikman

The phenomenology for the deep spatial geometry of loop quantum gravity is discussed. In the context of a simple model of an atom of space, it is shown how purely combinatorial structures can affect observations. The angle operator is used…

General Relativity and Quantum Cosmology · Physics 2015-06-03 Seth A. Major

We consider the coupling between massive and spinning particles and three dimensional gravity. This allows us to construct geometric operators (distances between particles) as Dirac observables. We quantize the system a la loop quantum…

General Relativity and Quantum Cosmology · Physics 2017-08-23 Karim Noui , Alejandro Perez

There is constructed and considered the extension of classical Diriclet operator corresponding to uniformly log-concave measure in the space of symmetric differential forms. Sufficient conditions for its essential self-adjointness in…

funct-an · Mathematics 2008-02-03 A. G. Us

Motivated by both concepts of R.J. Adler's recent work on utilizing Clifford algebra as the linear line element $ds = \left\langle \gamma_\mu \right\rangle dX^\mu $, and the fermionization of the cylindrical worldsheet Polyakov action, we…

High Energy Physics - Theory · Physics 2016-04-27 Hsu-Wen Chiang , Yao-Chieh Hu , Pisin Chen

One can try to define the theory of quantum gravity as the sum over geometries. In two dimensions the sum over {\it Euclidean} geometries can be performed constructively by the method of {\it dynamical triangulations}. One can define a {\it…

General Relativity and Quantum Cosmology · Physics 2017-08-23 J. Ambjorn

To adopt a practical method to calculate the action of geometrical operators on quantum states is a crucial task in loop quantum gravity. In the series of papers, we will introduce a graphical method, developed by Yutsis and Brink, to loop…

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

We propose a quantum gravity-extended form of the classical length contraction law obtained in Special Relativity. More specifically, the framework of our discussion is the UV self-complete theory of quantum gravity. Against this…

High Energy Physics - Theory · Physics 2013-10-01 Antonio Aurilia , Euro Spallucci

We study measures of quantum information when the space spanned by the set of accessible observables is not closed under products, i.e., we consider systems where an observer may be able to measure the expectation values of two operators,…

High Energy Physics - Theory · Physics 2018-08-15 Sudip Ghosh , Suvrat Raju

It is shown that the volume operator of a quantum tetrahedron is, in the sector of large eigenvalues, accurately described by a quantum harmonic oscillator. This result relies on the fact that (i) the volume operator couples only…

General Relativity and Quantum Cosmology · Physics 2013-11-01 John Schliemann

We introduce a quantum volume operator $K$ in three--dimensional Quantum Gravity by taking into account a symmetrical coupling scheme of three SU(2) angular momenta. The spectrum of $K$ is discrete and defines a complete set of eigenvectors…

General Relativity and Quantum Cosmology · Physics 2009-11-07 G. Carbone , M. Carfora , A. Marzuoli

Linearly polarized cylindrical waves in four-dimensional vacuum gravity are mathematically equivalent to rotationally symmetric gravity coupled to a Maxwell (or Klein-Gordon) field in three dimensions. The quantization of this latter system…

General Relativity and Quantum Cosmology · Physics 2010-11-19 Maria E. Angulo , Guillermo A. Mena Marugan

We propose a new type of gauge in two-dimensional quantum gravity. We investigate pure gravity in this gauge, and find that the system reduces to quantum mechanics of loop length $l$. Furthermore, we rederive the $c\!=\!0$ string field…

High Energy Physics - Theory · Physics 2009-10-22 M. Fukuma , N. Ishibashi , H. Kawai , M. Ninomiya