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Related papers: Contractive spectral triples for crossed products

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Axioms for nonunital spectral triples, extending those introduced in the unital case by Connes, are proposed. As a guide, and for the sake of their importance in noncommutative quantum field theory, the spaces $\R^{2N}$ endowed with Moyal…

High Energy Physics - Theory · Physics 2016-08-16 V. Gayral , J. M. Gracia-Bondía , B. Iochum , T. Schücker , J. C. Varilly

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

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 construct certain spectral triples in the sense of A. ~Connes and H. \~Moscovici (``The local index formula in noncommutative geometry'' {\it Geom. Funct. Anal.}, 5(2):174--243, 1995) that is transversally elliptic but not necessarily…

Differential Geometry · Mathematics 2007-05-23 Xiaodong Hu

We propose a construction for spectral triple on algebras associated with subshifts. One-dimensional subshifts provide concrete examples Z-actions on Cantor sets. The C*-algebra of this dynamical system is generated by functions in C(X) and…

Operator Algebras · Mathematics 2015-11-18 Antoine Julien , Ian F. Putnam

We show how to equip the crossed product between a group of polynomial growth and a compact quantum metric space with a compact quantum metric space structure. When the quantum metric on the base space arises from a spectral triple, which…

Operator Algebras · Mathematics 2024-12-02 Are Austad , Jens Kaad , David Kyed

We propose an expansion of the definition of almost-commutative spectral triple that accommodates non-trivial fibrations and is stable under inner fluctuation of the metric, and then prove a reconstruction theorem for almost-commutative…

Mathematical Physics · Physics 2012-07-02 Branimir Ćaćić

We decompose the crossed product functor for actions of crossed modules of locally compact groups on C*-algebras into more elementary constructions: taking crossed products by group actions and fibres in C*-algebras over topological spaces.…

Operator Algebras · Mathematics 2015-06-02 Alcides Buss , Ralf Meyer

We prove rigidity and classification results for type III factors given by nonsingular Bernoulli actions of the free groups and more general free product groups. This includes a large family of nonisomorphic Bernoulli crossed products of…

Operator Algebras · Mathematics 2023-07-11 Stefaan Vaes , Bram Verjans

We present a duality between the category of compact Riemannian spin manifolds (equipped with a given spin bundle and charge conjugation) with isometries as morphisms and a suitable "metric" category of spectral triples over commutative…

Operator Algebras · Mathematics 2011-12-30 Paolo Bertozzini , Roberto Conti , Wicharn Lewkeeratiyutkul

Semiclassical analysis and noncommutative geometry are two pillars of quantum theory. It is only recently that bridges between them have been emerging. In this monograph, we combine various techniques from functional analysis and spectral…

Operator Algebras · Mathematics 2026-05-27 Raphael Ponge

We present a systematic study of the structure of crossed products and fixed point algebras by compact group actions with the Rokhlin property on not necessarily unital C*-algebras. Our main technical result is the existence of an…

Operator Algebras · Mathematics 2016-05-31 Eusebio Gardella

We introduce a family of spectral triples that describe the curved noncommutative two-torus. The relevant family of new Dirac operators is given by rescaling one of two terms in the flat Dirac operator. We compute the dressed scalar…

Quantum Algebra · Mathematics 2018-06-04 Ludwik Dabrowski , Andrzej Sitarz

The notion of crossed product by a coquasi-bialgebra H is introduced and studied. The resulting crossed product is an algebra in the monoidal category of right H-comodules. We give an interpretation of the crossed product as an action of a…

Quantum Algebra · Mathematics 2008-11-27 Adriana Balan

In the abstract pseudodifferential setup of Connes and Moscovici, we prove a general formula for the discrepancies of zeta-regularised traces associated with certain spectral triples, and we introduce a canonical trace on operators, whose…

Operator Algebras · Mathematics 2010-09-30 Sylvie Paycha

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 examine the ideal structure of crossed products B\rtimes G where B is a continuous-trace C*-algebra and the induced action of G on the spectrum of B is proper. In particular, we are able to obtain a concrete description of the topology…

Operator Algebras · Mathematics 2012-08-23 Siegfried Echterhoff , Dana P. Williams

In this thesis, we studied certain mathematical issues related to the computation of the Chamseddine--Connes spectral action on some fundamental noncommutative spectral triples, such as the noncommutative torus and the quantum 3-sphere…

Mathematical Physics · Physics 2009-09-08 Cyril Levy

For a matched pair of locally compact quantum groups, we construct the double crossed product as a locally compact quantum group. This construction generalizes Drinfeld's quantum double construction. We study C*-algebraic properties of…

Operator Algebras · Mathematics 2007-05-23 Saad Baaj , Stefaan Vaes

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