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Related papers: Holonomy Loops, Spectral Triples & Quantum Gravity

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This paper establishes a link between Noncommutative Geometry and canonical quantum gravity. A semi-finite spectral triple over a space of connections is presented. The triple involves an algebra of holonomy loops and a Dirac type operator…

High Energy Physics - Theory · Physics 2009-11-13 Johannes Aastrup , Jesper M. Grimstrup , Ryszard Nest

We show that the principal part of the Dirac Hamiltonian in 3+1 dimensions emerges in a semi-classical approximation from a construction which encodes the kinematics of quantum gravity. The construction is a spectral triple over a…

High Energy Physics - Theory · Physics 2011-03-18 Johannes Aastrup , Jesper M. Grimstrup , Mario Paschke

The structure of the Dirac Hamiltonian in 3+1 dimensions is shown to emerge in a semi-classical approximation from a abstract spectral triple construction. The spectral triple is constructed over an algebra of holonomy loops, corresponding…

High Energy Physics - Theory · Physics 2010-03-22 Johannes Aastrup , Jesper M. Grimstrup , Mario Paschke

A new approach to a unified theory of quantum gravity based on noncommutative geometry and canonical quantum gravity is presented. The approach is built around a *-algebra generated by local holonomy-diffeomorphisms on a 3-manifold and a…

Mathematical Physics · Physics 2015-06-11 Johannes Aastrup , Jesper M. Grimstrup

We construct normalizable, semi-classical states for the previously proposed model of quantum gravity which is formulated as a spectral triple over holonomy loops. The semi-classical limit of the spectral triple gives the Dirac Hamiltonian…

High Energy Physics - Theory · Physics 2011-03-02 Johannes Aastrup , Jesper M. Grimstrup , Mario Paschke , Ryszard Nest

A new construction of a semifinite spectral triple on an algebra of holonomy loops is presented. The construction is canonically associated to quantum gravity and is an alternative version of the spectral triple presented in…

High Energy Physics - Theory · Physics 2011-03-02 Johannes Aastrup , Jesper M. Grimstrup , Ryszard Nest

We modify the construction of the spectral triple over an algebra of holonomy loops by introducing additional parameters in form of families of matrices. These matrices generalize the already constructed Euler-Dirac type operator over a…

High Energy Physics - Theory · Physics 2009-11-16 Johannes Aastrup , Jesper M. Grimstrup , Mario Paschke

The machinery of noncommutative geometry is applied to a space of connections. A noncommutative function algebra of loops closely related to holonomy loops is investigated. The space of connections is identified as a projective limit of…

High Energy Physics - Theory · Physics 2009-11-11 Johannes Aastrup , Jesper M. Grimstrup

We present quantum holonomy theory, which is a non-perturbative theory of quantum gravity coupled to fermionic degrees of freedom. The theory is based on a C*-algebra that involves holonomy-diffeomorphisms on a 3-dimensional manifold and…

General Relativity and Quantum Cosmology · Physics 2016-11-03 Johannes Aastrup , Jesper M. Grimstrup

A semifinite spectral triple for an algebra canonically associated to canonical quantum gravity is constructed. The algebra is generated by based loops in a triangulation and its barycentric subdivisions. The underlying space can be seen as…

High Energy Physics - Theory · Physics 2009-04-08 Johannes Aastrup , Jesper M. Grimstrup , Ryszard Nest

In this paper we construct a candidate for a spectral triple on a quotient space of gauge connections modulo gauge transformations and show that it is related to a Kasparov type bi-module over two canonical algebras: the HD-algebra, which…

High Energy Physics - Theory · Physics 2023-10-25 Johannes Aastrup , Jesper M. Grimstrup

Loop quantum gravity in its Hamiltonian form relies on a connection formulation of the gravitational phase space with three key properties: 1.) a compact gauge group, 2.) real variables, and 3.) canonical Poisson brackets. In conjunction,…

General Relativity and Quantum Cosmology · Physics 2024-12-09 Norbert Bodendorfer , Konstantin Eder , Xiangdong Zhang

We introduce the Quantum Holonomy-Diffeomorphism *-algebra, which is generated by holonomy-diffeomorphisms on a 3-dimensional manifold and translations on a space of SU(2)-connections. We show that this algebra encodes the canonical…

General Relativity and Quantum Cosmology · Physics 2016-04-12 Johannes Aastrup , Jesper M. Grimstrup

The system of gravity coupled to the non-rotational dust field is studied at both classical and quantum levels. The scalar constraint of the system can be written in the form of a true physical Hamiltonian with respect to the dust time. In…

General Relativity and Quantum Cosmology · Physics 2023-11-15 Xiangdong Zhang , Yongge Ma

The loop quantization of Brans-Dicke theory (with coupling parameter $\omega\neq-3/2$) is studied. In the geometry-dynamical formalism, the canonical structure and constraint algebra of this theory are similar to those of general relativity…

General Relativity and Quantum Cosmology · Physics 2012-05-18 Xiangdong Zhang , Yongge Ma

In the last 20 years, loop quantum gravity, a background independent approach to unify general relativity and quantum mechanics, has been widely investigated. The aim of loop quantum gravity is to construct a mathematically rigorous,…

General Relativity and Quantum Cosmology · Physics 2007-06-25 Muxin Han

In attempts to combine non-commutative geometry and quantum gravity, Aastrup-Grimstrup-Nest construct a semi-finite spectral triple, modeling the space of G-connections for G=U(1) or SU(2). AGN show that the interaction between the algebra…

Mathematical Physics · Physics 2010-10-26 Alan Lai

In this paper we establish the existence of the non-perturbative theory of quantum gravity known as quantum holonomy theory by showing that a Hilbert space representation of the QHD(M) algebra, which is an algebra generated by…

General Relativity and Quantum Cosmology · Physics 2018-09-18 Johannes Aastrup , Jesper M. Grimstrup

We summarize our work on spherically symmetric midi-superspaces in loop quantum gravity. Our approach is based on using inhomogeneous slicings that may penetrate the horizon in case there is one and on a redefinition of the constraints so…

General Relativity and Quantum Cosmology · Physics 2025-05-14 Rodolfo Gambini , Javier Olmedo , Jorge Pullin

We construct a Connes spectral triple or `Dirac operator' on the non-reduced fuzzy sphere $C_\lambda[S^2]$ as realised using quantum Riemannian geometry with a central quantum metric $g$ of Euclidean signature and its associated quantum…

Quantum Algebra · Mathematics 2022-02-09 Evelyn Lira-Torres , Shahn Majid
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