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Spectral triples and quantum statistical mechanical systems are two important constructions in noncommutative geometry. In particular, both lead to interesting reconstruction theorems for a broad range of geometric objects, including number…

Mathematical Physics · Physics 2013-05-24 Mark Greenfield , Matilde Marcolli , Kevin Teh

We prove a local index formula in conformal geometry by computing the Connes-Chern character for the conformal Dirac (twisted) spectral triple recently constructed by Connes-Moscovici. Following an observation of Moscovici, the computation…

Operator Algebras · Mathematics 2014-11-17 Raphael Ponge , Hang Wang

We investigate a smoothing property for strongly-continuous operator semigroups, akin to ultracontractivity in parabolic evolution equations. Specifically, we establish the stability of this property under certain relatively bounded…

Analysis of PDEs · Mathematics 2026-05-12 Sahiba Arora , Jonathan Mui

The spectral torsion is defined by three vector fields and Dirac operators and the noncommutative residue. Motivated by the spectral torsion and the one form rescaled Dirac operator, we give some new spectral torsion which is the extension…

Differential Geometry · Mathematics 2025-05-30 Jian Wang , Yong Wang

This article demonstrates how the transition from a (Riemannian) twisted spectral triple to a pseudo-Riemannian spectral triple arises within an almost-commutative spectral triple. This opens a new perspective on the Lorentzian signature…

Mathematical Physics · Physics 2025-05-07 Gaston Nieuviarts

In this paper we prove a version of Connes' trace theorem for noncommutative tori of any dimension~$n\geq 2$. This allows us to recover and improve earlier versions of this result in dimension $n=2$ and $n=4$ by Fathizadeh-Khalkhali. We…

Operator Algebras · Mathematics 2020-05-20 Raphael Ponge

We construct spectral metric spaces for Gibbs measures on a one-sided topologically exact subshift of finite type. That is, for a given Gibbs measure we construct a spectral triple and show that Connes' corresponding pseudo-metric is a…

Operator Algebras · Mathematics 2017-10-24 Marc Kesseböhmer , Tony Samuel

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

In the context of A. Connes' spectral triples, a suitable notion of morphism is introduced. Discrete groups with length function provide a natural example for our definitions. A. Connes' construction of spectral triples for group algebras…

Operator Algebras · Mathematics 2007-05-23 Paolo Bertozzini , Roberto Conti , Wicharn Lewkeeratiyutkul

We generalize the notion of spectral triple with reality structure to spectral triples with multitwisted real structure, the class of which is closed under the tensor product composition. In particular, we introduce a multitwisted order one…

Quantum Algebra · Mathematics 2020-11-13 Ludwik Dabrowski , Andrzej Sitarz

The twined almost commutative structure of the standard spectral triple on the noncommutative torus with rational parameter is exhibited, by showing isomorphisms with a spectral triple on the algebra of sections of certain bundle of…

Quantum Algebra · Mathematics 2019-06-26 Alessandro Carotenuto , Ludwik Dabrowski

We extend a classification of irreducible, almost commutative geometries whose spectral action is dynamically non-degenerate to internal algebras that have four simple summands.

High Energy Physics - Theory · Physics 2009-11-11 Jan-Hendrik Jureit , Thomas Schucker , Christoph Stephan

In this paper we study spectral triples and non-commutative expectations associated to expanding and weakly expanding maps. In order to do so, we generalize the Perron-Frobenius-Ruelle theorem and obtain a polynomial decay of the operator,…

Dynamical Systems · Mathematics 2024-03-27 Leandro Cioletti , L. Y. Hataishi , Artur O. Lopes , M. Stadlbauer

Twisted spectral triples are a twisting of the notion of spectral triple aiming at dealing with some type III geometric situations. In the first part of the paper, we give a geometric construction of the index map of a twisted spectral…

Operator Algebras · Mathematics 2016-06-08 Raphael Ponge , Hang Wang

We describe a way to deform spectral triples with a 2-torus action and a real deformation parameter, motivated by deformation of manifolds after Connes-Landi. Such deformations are shown to have naturally isomorphic $K$-theoretic invariants…

Operator Algebras · Mathematics 2011-03-30 Makoto Yamashita

Having in view the study of a version of Gel'fand-Neumark duality adapted to the context of Alain Connes' spectral triples, in this very preliminary review, we first present a description of the relevant categories of geometrical spaces,…

Operator Algebras · Mathematics 2014-09-05 Paolo Bertozzini , Fred Jaffrennou

Continuing previous work we develop a certain piece of functional analysis on general graphs and use it to create what Connes calls a 'spectral triple', i.e. a Hilbert space structure, a representation of a certain (function) algebra and a…

High Energy Physics - Theory · Physics 2008-02-03 M. Requardt

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

This article is concerned with a generalisation of Connes' noncommutative framework. This is achieved by a general study of spectral triples, in particular through an analysis of the role played by the Dirac operator. The Dirac operator is…

Mathematical Physics · Physics 2018-06-27 Nikhil Kalyanapuram

We discuss the Fubini formula in Alain Connes' noncommutative geometry. We present a sufficient condition on spectral triples for which a Fubini formula holds true. The condition is natural and related to heat semigroup asymptotics. We…

Operator Algebras · Mathematics 2016-12-14 Fedor Sukochev , Dmitriy Zanin