English
Related papers

Related papers: Sequences from zero entropy noncommutative toral a…

200 papers

We show that for every "locally finite" unit-preserving completely positive map P acting on a C*-algebra, there is a corresponding *-automorphism \alpha of another unital C*-algebra such that the two sequences P, P^2,P^3,... and \alpha,…

Operator Algebras · Mathematics 2007-05-23 William Arveson

Let $A$ be an algebraically simple, separable, nuclear, $\mathcal{Z}$-stable $C^*$-algebra for which the trace space $T(A)$ is a Bauer simplex and the extremal boundary $\partial_e T(A)$ has finite covering dimension. We prove that each…

Operator Algebras · Mathematics 2023-04-18 Lise Wouters

We explicitly compute the spectral metric, torsion and Einstein tensors for a nontrivial spectral triple on a noncommutative torus, with the Dirac operator related to the fully equivariant Dirac by a partial conformal rescaling (as…

Quantum Algebra · Mathematics 2026-03-12 Deeponjit Bose , Andrzej Sitarz

The notion of a $*$-law or $*$-distribution in free probability is also known as the quantifier-free type in Farah, Hart, and Sherman's model theoretic framework for tracial von Neumann algebras. However, the full type can also be…

Operator Algebras · Mathematics 2022-08-31 David Jekel

We first give a relative flexible process to construct torsion cohomology classes for Shimura varieties of Kottwitz-Harris-Taylor type with coefficient in a non too regular local system. We then prove that associated to each torsion…

Number Theory · Mathematics 2017-01-03 Pascal Boyer

Let $G$ be an inductive limit of finite cyclic groups and let $A$ be a unital simple projectionless C*-algebra with $K_1(A) \cong G$ and with a unique tracial state, as constructed based on dimension drop algebras by Jiang and Su. First, we…

Operator Algebras · Mathematics 2008-07-31 Yasuhiko Sato

We investigate connections between resolvability and different forms of tightness. This study is adjacent to [1,2]. We construct a non-regular refinement $\tau^*$ of the natural topology of the real line $\mathbb{R}$ with properties such…

General Topology · Mathematics 2025-07-29 Anton Lipin

We study generating series of torus integrals that contain all so-called modular graph forms relevant for massless one-loop closed-string amplitudes. By analysing the differential equation of the generating series we construct a solution…

High Energy Physics - Theory · Physics 2020-08-26 Jan E. Gerken , Axel Kleinschmidt , Oliver Schlotterer

In the process of developing the theory of free probability and free entropy, Voiculescu introduced in 1991 a random matrix model for a free semicircular system. Since then, random matrices have played a key role in von Neumann algebra…

Operator Algebras · Mathematics 2007-06-21 Uffe Haagerup , Steen Thorbjornsen

Let $A \in M_{n}(\mathbb{R})$ be an invertible matrix. Consider the semi-direct product $\mathbb{R}^{n} \rtimes \mathbb{Z}$ where $\mathbb{Z}$ acts on $\mathbb{R}^{n}$ by matrix multiplication. Consider a strongly continuous action…

Operator Algebras · Mathematics 2012-03-05 S. Sundar

We present a proof for certain cases of the noncommutative Borsuk-Ulam conjectures proposed by Baum, D\k{a}browski, and Hajac. When a unital $C^*$-algebra $A$ admits a free action of $\mathbb{Z}/k\mathbb{Z}$, $k \geq 2$, there is no…

Operator Algebras · Mathematics 2019-07-04 Benjamin Passer

Gelfand - Na\u{i}mark theorem supplies contravariant functor from a category of commutative $C^*-$ algebras to a category of locally compact Hausdorff spaces. Therefore any commutative $C^*-$ algebra is an alternative representation of a…

Operator Algebras · Mathematics 2014-01-28 Petr R. Ivankov

Let $A$ be a C*-algebra that is the norm closure $A = \overline{\sum_{\beta \in \alpha} I_\beta}$ of an arbitrary sum of C*-ideals $I_\beta \subseteq A$. We construct a homological spectral sequence that takes as input the K-theory of…

K-Theory and Homology · Mathematics 2019-05-13 Simon Naarmann

The zero-entropy-density conjecture states that the entropy density, defined as the limit of S(N)/N at infinity, vanishes for all translation-invariant pure states on the spin chain. Or equivalently, S(N), the von Neumann entropy of such a…

Mathematical Physics · Physics 2009-11-11 S. Farkas , Z. Zimboras

We replaced the classical string theory notions of parameter space and world-time with noncommutative tori and consider maps between these spaces. The dynamics of mappings between different noncommutative tori were studied and a…

Operator Algebras · Mathematics 2012-08-02 Mauritz van den Worm

We investigate field theories on the non-commutative torus upon varying theta, the parameter of non-commutativity. We argue that one should think of Morita equivalence as a symmetry of algebras describing the same space rather than of…

High Energy Physics - Theory · Physics 2007-05-23 Robert C. Helling

We describe a new regularization of quantum field theory on the noncommutative torus by means of one-dimensional matrix models. The construction is based on the Elliott-Evans inductive limit decomposition of the noncommutative torus…

High Energy Physics - Theory · Physics 2010-04-05 Giovanni Landi , Fedele Lizzi , Richard J. Szabo

We show that, for many choices of finite tuples of generators $X = (x_1, \dots , x_d)$ of a tracial von Neumann algebra $(M, \tau)$ satisfying certain decomposition properties (non-primeness, possessing a Cartan subalgebra, or property…

Operator Algebras · Mathematics 2025-11-18 Benjamin Major , Dimitri Shlyakhtenko

In this paper, we introduce topological dynamical systems with almost countable spectrum. We prove that the Logarithmic Sarnak Conjecture holds for zero-entropy topological dynamical systems whose spectrum is almost countable. This class…

Dynamical Systems · Mathematics 2025-11-07 Wen Huang , Maoru Tan , Leiye Xu

We show that the images via $z\mapsto z^m$ of the continuous part of the spectral measures of the dynamical systems generated by the 0-1 sequences of the Thue-Morse type are pairwise mutually singular for different odd numbers $m\in\N$.…

Dynamical Systems · Mathematics 2013-10-11 El Houcein El Abdalaoui , Stanisław Kasjan , Mariusz Lemańczyk