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We construct a canonical geometrically realised Connes spectral triple or `Dirac operator' $D\!\!\!/$ from the data of a quantum metric $g\in \Omega^1\otimes_A\Omega^1$ and quantum Levi-Civita bimodule connection, at the pre-Hilbert space…

Quantum Algebra · Mathematics 2023-05-16 Shahn Majid

In this paper we extend the traditional framework of noncommutative geometry in order to deal with spectral truncations of geometric spaces (i.e. imposing an ultraviolet cutoff in momentum space) and with tolerance relations which provide a…

Quantum Algebra · Mathematics 2020-08-26 Alain Connes , Walter D. van Suijlekom

We first identify (up to linear isomorphism) the Lipschitz free spaces of quasiarcs. By decomposing quasiconformal trees into quasiarcs as done in an article of David, Eriksson-Bique, and Vellis, we then identify the Lipschitz free spaces…

Metric Geometry · Mathematics 2023-03-16 David M. Freeman , Chris Gartland

We show that the first five of the axioms we had formulated on spectral triples suffice (in a slightly stronger form) to characterize the spectral triples associated to smooth compact manifolds. The algebra, which is assumed to be…

Operator Algebras · Mathematics 2008-10-14 Alain Connes

We examine the metric and Einstein bilinear functionals of differential forms introduced in Adv.Math.,Vol.427,(2023)1091286, for Hodge-Dirac operator $d+\delta$ on an oriented even-dimensional Riemannian manifold. We show that they…

Differential Geometry · Mathematics 2024-08-22 Ludwik Dąbrowski , Paweł Zalecki , Andrzej Sitarz

The Dirac operator is considered on a bidimensional domain whose boundary carries the infinite mass boundary condition. The analysis is focused on the existence of discrete spectrum and on its asymptotic description in the thin width limit.…

Mathematical Physics · Physics 2024-10-01 Loïc Le Treust , Thomas Ourmières-Bonafos , Nicolas Raymond

Let X be a compact manifold with boundary, and suppose that the boundary is the total space of a fibration with base Y and fibre Z. Let D be a generalized Dirac operator associated to a Phi-metric g on X. Under the assumption that D is…

Differential Geometry · Mathematics 2007-05-23 Eric Leichtnam , Rafe Mazzeo , Paolo Piazza

This article is one of a series of papers. For this decade, the Dirac operator on a submanifold has been studied as a restriction of the Dirac operator in $n$-dimensional euclidean space $\EE^n$ to a surface or a space curve as physical…

Differential Geometry · Mathematics 2007-05-23 Shigeki Matsutani

We construct in projective differential geometry of the real dimension $2$ higher symmetry algebra of the symplectic Dirac operator ${D}\kern-0.5em\raise0.22ex\hbox{/}_s$ acting on symplectic spinors. The higher symmetry differential…

Differential Geometry · Mathematics 2018-03-20 Petr Somberg , Josef Šilhan

Following our work from the previous paper about the study of effective Dirac algebra and the metric of the simple, special case of relativistic hydrogen atom, this paper gives the complete metric study defined by the effective Dirac…

General Physics · Physics 2022-04-04 B. T. T. Wong

We describe a construction of fibrewise inner products on the cotangent bundle of the smooth free loop space of a Riemannian manifold. Using this inner product, we construct an operator over the loop space of a string manifold which is…

Differential Geometry · Mathematics 2007-05-23 Andrew Stacey

We study the spectrum of random operators on a large class of trees. These trees have finitely many cone types and they can be constructed by a substitution rule. The random operators are perturbations of Laplace type operators either by…

Mathematical Physics · Physics 2011-08-02 Matthias Keller , Daniel Lenz , Simone Warzel

We construct Dirac operators and spectral triples for certain, not necessarily self-similar, fractal sets built on curves. Connes' distance formula of noncommutative geometry provides a natural metric on the fractal. To motivate the…

Metric Geometry · Mathematics 2015-06-16 Michel L. Lapidus , Jonathan J. Sarhad

In this work we study Dirac operators on two-dimensional domains coupled to a magnetic field perpendicular to the plane. We focus on the infinite-mass boundary condition (also called MIT bag condition). In the case of bounded domains, we…

Analysis of PDEs · Mathematics 2021-05-05 Jean-Marie Barbaroux , Loïc Le Treust , Nicolas Raymond , Edgardo Stockmeyer

There are several interrelated notions of discrete curvature on graphs. Many approaches utilize the optimal transportation metric on its probability simplex or the distance matrix of the graph. In this survey article, we compute formulas…

Combinatorics · Mathematics 2025-11-04 Sawyer Jack Robertson

It is well-known that the spectrum of a $\text{spin}^{\mathbb{C}}$ Dirac operator on a closed Riemannian $\text{spin}^{\mathbb{C}}$ manifold $M^{2k}$ of dimension $2k$ for $k \in \mathbb{N}$ is symmetric. In this article, we prove that over…

Differential Geometry · Mathematics 2013-08-27 Kyusik Hong , Chanyoung Sung

Recently Dabrowski etc. \cite{DL} obtained the metric and Einstein functionals by two vector fields and Laplace-type operators over vector bundles, giving an interesting example of the spinor connection and square of the Dirac operator.…

Differential Geometry · Mathematics 2024-05-21 Jian Wang , Yong Wang , Tong Wu

We study an abstract notion of tree structure which lies at the common core of various tree-like discrete structures commonly used in combinatorics: trees in graphs, order trees, nested subsets of a set, tree-decompositions of graphs and…

Combinatorics · Mathematics 2017-02-28 Reinhard Diestel

We construct several natural connections and Dirac type operators on a general metric contact manifold which are more sensitive to the geometric background. In the special case of CR manifolds these connections are also compatible with the…

Differential Geometry · Mathematics 2007-05-23 Liviu I. Nicolaescu

The aim of the present paper is to introduce the notion of first order (supersymmetric) Dirac operators on discrete and metric (``quantum'') graphs. In order to cover all self-adjoint boundary conditions for the associated metric graph…

Spectral Theory · Mathematics 2007-09-03 Olaf Post