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Related papers: KMS states on $\mathbb{Z}_2$-crossed products and …

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We develop the theory of quasi--invariant (resp. strongly quasi--invariant) states under the action of a group $G$ of normal $*$--automorphisms of a $*$--algebra (or von Neumann alegbra) $\mathcal{A}$. We prove that these states are…

Mathematical Physics · Physics 2024-01-17 Luigi Accardi , Ameur Dhahri

We study the generalised Bunce-Deddens algebras and their Toeplitz extensions constructed by Kribs and Solel from a directed graph and a sequence $\omega$ of positive integers. We describe both of these $C^*$-algebras in terms of novel…

Operator Algebras · Mathematics 2015-10-14 David Robertson , James Rout , Aidan Sims

We describe the representation theory of C*-crossed-products of a unital C*-algebra A by the cyclic group of order 2. We prove that there are two main types of irreducible representations for the crossed-product: those whose restriction to…

Operator Algebras · Mathematics 2011-10-10 Man-Duen Choi , Frederic Latremoliere

The paper develops a method to construct one-parameter groups of automorphisms on the CAR C*-algebra with a prescribed field of KMS states.

Operator Algebras · Mathematics 2018-11-20 Klaus Thomsen

Given two correspondences $X$ and $Y$ and a discrete group $G$ which acts on $X$ and coacts on $Y$, one can define a twisted tensor product $X\boxtimes Y$ which simultaneously generalizes ordinary tensor products and crossed products by…

Operator Algebras · Mathematics 2016-01-29 Adam Morgan

An integer matrix $A\in M_d(\Z)$ induces a covering $\sigma_A$ of $\T^d$ and an endomorphism $\alpha_A:f\mapsto f\circ \sigma_A$ of $C(\T^d)$ for which there is a natural transfer operator $L$. In this paper, we compute the KMS states on…

Operator Algebras · Mathematics 2011-01-26 Marcelo Laca , Iain Raeburn , Jacqui Ramagge

We complete the analysis of KMS-states of the Toeplitz algebra of the affine semigroup over the natural numbers, recently studied by Raeburn and the first author, by showing that for every inverse temperature beta in the critical interval…

Operator Algebras · Mathematics 2010-10-05 Marcelo Laca , Sergey Neshveyev

It is known that any locally faithful quantum Markov state (QMS) on one dimensional setting can be considered as a Gibbs state associated with Hamiltonian with commuting nearest-neighbor interactions. In our previous results, we have…

Mathematical Physics · Physics 2019-04-12 Farrukh Mukhamedov , Abdessatar Souissi

In this paper, we investigate the topological full groups arising from the Cuntz and Cuntz-Toeplitz algebras and their crossed products with the Cartan subalgebras of Cuntz and Cuntz-Toeplitz algebras. We study the normal subgroups and…

Operator Algebras · Mathematics 2025-10-01 Ryoya Arimoto , Taro Sogabe

von Neumann algebras have been playing an increasingly important role in the context of gauge theories and gravity. The crossed product presents a natural method for implementing constraints through the commutation theorem, rendering it a…

High Energy Physics - Theory · Physics 2025-02-10 Shadi Ali Ahmad , Marc S. Klinger , Simon Lin

A systematic and compact treatment of arbitrary $su(2)$ invariant spin-$s$ quantum chains with nearest-neighbour interactions is presented. The ground-state is derived in terms of matrix product states (MPS). The fundamental MPS…

Strongly Correlated Electrons · Physics 2016-08-24 Rubina Zadourian , Andreas Fledderjohann , Andreas Klümper

We investigate the factor types of the extremal KMS states for the preferred dynamics on the Toeplitz algebra and the Cuntz--Krieger algebra of a strongly connected finite $k$-graph. For inverse temperatures above 1, all of the extremal KMS…

Operator Algebras · Mathematics 2021-06-10 Marcelo Laca , Nadia S. Larsen , Sergey Neshveyev , Aidan Sims , Samuel B. G. Webster

Building on an argument by Toms and Winter, we show that if $A$ is a simple, separable, unital, $\mathcal{Z}$-stable C*-algebra, then the crossed product of $C(X,A)$ by an automorphism is also Z-stable, provided that the automorphism…

Operator Algebras · Mathematics 2016-09-01 Julian Buck

To a continuous action of a vector group on a $C^*$-algebra, twisted by the imaginary exponential of a symplectic form, one associates a Rieffel deformed algebra as well as a twisted crossed product. We show that the second one is…

Operator Algebras · Mathematics 2014-06-30 I. Beltita , M. Mantoiu

Let $\Omega$ be a tiling space and let $G$ be the maximal group of rotations which fixes $\Omega$. Then the cohomology of $\Omega$ and $\Omega/G$ are both invariants which give useful geometric information about the tilings in $\Omega$. The…

Operator Algebras · Mathematics 2015-06-17 Charles Starling

In this paper, we study bimodules over a von Neumann algebra $M$ in two related contexts. The first is an inclusion $M \subseteq M \rtimes_\alpha G$, where $G$ is a discrete group acting on a factor $M$ by outer automorphisms. The second is…

Operator Algebras · Mathematics 2014-01-16 Jan Cameron , Roger R. Smith

We consider a crossed product of a unital simple separable nuclear stably finite Z-stable C*-algebra A by a strongly outer cocycle action of a discrete countable amenable group \Gamma. Under the assumption that A has finitely many extremal…

Operator Algebras · Mathematics 2017-08-23 Hiroki Matui , Yasuhiko Sato

There is a connection between the Weyl pseudodifferential calculus and crossed product C*-algebras associated with certain dynamical systems. And in fact both topics are involved in the quantization of a non-relativistic particle moving in…

Mathematical Physics · Physics 2007-05-23 Marius Mantoiu , Radu Purice , Serge Richard

Given a countably infinite 0-1 matrix A without identically zero rows, let O_A be the Cuntz-Krieger algebra recently introduced by the authors and T_A be the Toeplitz extension of O_A, once the latter is seen as a Cuntz-Pimsner algebra, as…

Operator Algebras · Mathematics 2007-05-23 Ruy Exel , Marcelo Laca

For a finite, strongly connected $k$-graph $\Lambda$, an Huef, Laca, Raeburn and Sims studied the KMS states associated to the preferred dynamics of the $k$-graph $C^*$-algebra $C^*(\Lambda)$. They found that these KMS states are determined…

Operator Algebras · Mathematics 2018-07-24 Carla Farsi , Elizabeth Gillaspy , Nadia S. Larsen , Judith A. Packer
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