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A supersymmetric theory in two-dimensions has enough data to define a noncommutative space thus making it possible to use all tools of noncommutative geometry. In particular, we apply this to the N=1 supersymmetric non-linear sigma model…

High Energy Physics - Theory · Physics 2009-10-30 A. H. Chamseddine

We consider the class of non-Hermitian operators represented by infinite tridiagonal matrices, selfadjoint in an indefinite inner product space with one negative square. We approximate them with their finite truncations. Both infinite and…

Mathematical Physics · Physics 2016-08-08 Maxim Derevyagin , Luca Perotti , Michal Wojtylak

We study the quantum Gromov-Hausdorff convergence of spectral truncations for compact quantum groups. Using a proper length function, we define a Dirac operator and the associated spectral truncations. This work extends the previous…

Operator Algebras · Mathematics 2026-05-01 Xintao Peng , Qin Wang

On a discrete group G a length function may implement a spectral triple on the reduced group C*-algebra. Following A. Connes, the Dirac operator of the triple then can induce a metric on the state space of reduced group C*-algebra. Recent…

Operator Algebras · Mathematics 2007-05-23 Cristina Antonescu , Erik Christensen

Joint spectra of tuples of operators are subsets in complex projective space. The corresponding tuple of operators can be viewed as an infinite dimensional analog of a determinantal representation of the joint spectrum. We investigate the…

Spectral Theory · Mathematics 2015-09-22 Michael Stessin , Alexandre Tchernev

How does the spectrum of a Schr\"odinger operator vary if the corresponding geometry and dynamics change? Is it possible to define approximations of the spectrum of such operators by defining approximations of the underlying structures? In…

Spectral Theory · Mathematics 2019-10-01 Siegfried Beckus , Jean Bellissard , Giuseppe De Nittis

We establish a spectral duality for certain unbounded operators in Hilbert space. The class of operators includes discrete graph Laplacians arising from infinite weighted graphs. The problem in this context is to establish a practical…

Functional Analysis · Mathematics 2008-08-05 Dorin Ervin Dutkay , Palle E. T. Jorgensen

We describe the $C^*$-algebra associated with the finite sections discretization of truncated Toeplitz operators on the model space $K^2_u$ where $u$ is an infinite Blaschke product. As consequences, we get a stability criterion for the…

Operator Algebras · Mathematics 2014-01-22 Steffen Roch

We explore the geometric implications of introducing a spectral cut-off on Riemannian manifolds. This is naturally phrased in the framework of non-commutative geometry, where we work with spectral triples that are \emph{truncated} by…

Mathematical Physics · Physics 2020-06-16 Lisa Glaser , Abel B. Stern

In this paper we derive novel families of inclusion sets for the spectrum and pseudospectrum of large classes of bounded linear operators, and establish convergence of particular sequences of these inclusion sets to the spectrum or…

Spectral Theory · Mathematics 2024-06-11 Simon N. Chandler-Wilde , Ratchanikorn Chonchaiya , Marko Lindner

Classical spectral theory gives a complete description of a single normal operator, but it fails for noncommuting operators, where no canonical joint spectrum or simultaneous diagonalization exists. Existing approaches provide only partial…

Category Theory · Mathematics 2026-01-27 Shih-Yu Chang

We investigate the effect of non-symmetric relatively bounded perturbations on the spectrum of self-adjoint operators. In particular, we establish stability theorems for one or infinitely many spectral gaps along with corresponding…

Spectral Theory · Mathematics 2016-04-04 Jean-Claude Cuenin , Christiane Tretter

This article surveys the noncommutative-geometric (NCG) approach to fundamental physics, in which geometry is encoded spectrally by a generalized Dirac operator and where dynamics arise from the spectral action. I review historically how…

High Energy Physics - Theory · Physics 2025-11-11 Ali H. Chamseddine

The purpose of this article is to apply the concept of the spectral triple, the starting point for the analysis of noncommutative spaces in the sense of A.~Connes, to the case where the algebra $\cA$ contains both bosonic and fermionic…

High Energy Physics - Theory · Physics 2009-10-30 W. Kalau , M. Walze

We explore the relation between noncommutative geometry, in the spectral triple formulation, and quantum mechanics. To this aim, we consider a dynamical theory of a noncommutative geometry defined by a spectral triple, and study its…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Carlo Rovelli

Almost commutative models provide a framework for Connes' work on the standard model of particle physics. These models are constructed as products of a the canonical spectral triple of a compact connected spin manifold with a finite…

Operator Algebras · Mathematics 2026-03-20 Frederic Latremoliere

As an outgrowth of our investigation of non-regular spaces within the context of quantum gravity and non-commutative geometry, we develop a graph Hilbert space framework on arbitrary (infinite) graphs and use it to study spectral properties…

Mathematical Physics · Physics 2016-09-07 Manfred Requardt

We review recent progress in the analytic study of random matrix models suggested by noncommutative geometry. One considers fuzzy spectral triples where the space of possible Dirac operators is assigned a probability distribution. These…

High Energy Physics - Theory · Physics 2022-10-12 Hamed Hessam , Masoud Khalkhali , Nathan Pagliaroli , Luuk Verhoeven

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

We propose a method for the spectral analysis of unbounded operator matrices in a general setting which fully abstains from standard perturbative arguments. Rather than requiring the matrix to act in a Hilbert space $\mathcal{H}$, we extend…

Spectral Theory · Mathematics 2022-05-25 Borbala Gerhat