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Related papers: $C^*$-fermi systems and detailed balance

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In the paper, we give two new characterizations of separable inner quasidiagonal C*-algebras. Base on these characterizations, we show that a unital full free product of two inner quasidiagonal C*-algebras is inner quasidiagonal again. As…

Operator Algebras · Mathematics 2015-04-21 Qihui Li

We study completely contractive representations of product systems of $C^*$-correspondences over semigroups. For a product system of $C^*$-correspondences over the semigroup $\mathbb{N}^2$, we prove that every such representation can be…

Operator Algebras · Mathematics 2007-05-23 Baruch Solel

A cohomology for product systems of Hilbert bimodules is defined via the Ext functor. For the class of product systems corresponding to irreversible algebraic dynamics, relevant resolutions are found explicitly and it is shown how the…

Operator Algebras · Mathematics 2017-04-05 Jeong Hee Hong , Mi Jung Son , Wojciech Szymanski

This paper is the first in a series of papers developing a functional-analytic theory of vertex (operator) algebras and their representations. For an arbitrary Z-graded finitely-generated vertex algebra (V, Y, 1) satisfying the standard…

Quantum Algebra · Mathematics 2009-10-31 Yi-Zhi Huang

It is proved that the reduced group C*-algebra C*_{red}(G) has stable rank one (i.e. its group of invertible elements is a dense subset) if G is a discrete group arising as a free product G_1*G_2 where |G_1|>=2 and |G_2|>=3. This follows…

funct-an · Mathematics 2008-02-03 Ken Dykema , Uffe Haagerup , Mikael Rordam

Let $1 \in A \subset B$ be an inclusion of C*-algebras of C*-index-finite type with depth 2. We try to compute topological stable rank of $B$ ($= \tsr(B)$) when $A$ has topological stable rank one. We show that $\tsr(B) \leq 2$ when $A$ is…

Operator Algebras · Mathematics 2016-09-07 Hiroyuki Osaka , Tamotsu Teruya

We study selflessness in the general setting of reduced free products of $C^*$-algebras. Towards this end, we develop a suitable theory of rapid decay for filtrations in arbitrary $C^*$-probability spaces. We provide several natural…

Operator Algebras · Mathematics 2025-06-17 Ben Hayes , Srivatsav Kunnawalkam Elayavalli , Leonel Robert

In the present paper we study tensor C*-categories with non-simple unit realised as C*-dynamical systems (F,G,\beta) with a compact (non-Abelian) group G and fixed point algebra A := F^G. We consider C*-dynamical systems with minimal…

Operator Algebras · Mathematics 2011-11-18 Fernando Lledó , Ezio Vasselli

An operator system modulo the kernel of a completely positive linear map of the operator system gives rise to an operator system quotient. In this paper, operator system quotients and quotient maps of certain matrix algebras are considered.…

Operator Algebras · Mathematics 2011-07-25 Douglas Farenick , Vern I. Paulsen

Tensor network states and specifically matrix-product states have proven to be a powerful tool for simulating ground states of strongly correlated spin models. Recently, they have also been applied to interacting fermionic problems,…

Quantum Physics · Physics 2016-11-22 C. Krumnow , L. Veis , Ö. Legeza , J. Eisert

Given positive integers n and m, we consider dynamical systems in which n copies of a topological space is homeomorphic to m copies of that same space. The universal such system is shown to arise naturally from the study of a C*-algebra we…

Operator Algebras · Mathematics 2011-09-20 Pere Ara , Ruy Exel , Takeshi Katsura

Different (fibrewise) amalgamated products of continuous C*-bundles have been studied over the last years, one of the main question being to know when these amalgamated products are continuous C*-bundles. In order to gather these approaches…

Operator Algebras · Mathematics 2008-03-03 Etienne Blanchard

We study strong compactly aligned product systems of $\mathbb{Z}_+^N$ over a C*-algebra $A$. We provide a description of their Cuntz-Nica-Pimsner algebra in terms of tractable relations coming from ideals of $A$. This approach encompasses…

Operator Algebras · Mathematics 2019-07-17 Adam Dor-On , Evgenios T. A. Kakariadis

We consider a certain class of unital simple stably finite C^*-algebras which absorb the Jiang-Su algebra Z tensorially. Under a mild assumption, we show that the crossed product of a C^*-algebra in this class by a strongly outer action of…

Operator Algebras · Mathematics 2011-07-05 Hiroki Matui , Yasuhiko Sato

We compute the K-theory for C*-algebras naturally associated with rings of integers in number fields. The main ingredient is a duality theorem for arbitrary global fields. It allows us to identify the crossed product arising from affine…

Operator Algebras · Mathematics 2009-06-29 Joachim Cuntz , Xin Li

I combine recent results in the structure theory of nuclear C*-algebras and in topological dynamics to classify certain types of crossed products in terms of their Elliott invariants. In particular, transformation group C*-algebras…

Operator Algebras · Mathematics 2015-04-08 Wilhelm Winter

There is a famous multiplication table of types of tensor product of two von Neumann algebras. We filled out the multiplication table of graded tensor product of two graded von Neumann algebras in special cases.

Operator Algebras · Mathematics 2025-08-15 Jumpei Tanaka

We extend the recently introduced continuous matrix product state (cMPS) variational class to the setting of (1+1)-dimensional relativistic quantum field theories. This allows one to overcome the difficulties highlighted by Feynman…

High Energy Physics - Theory · Physics 2012-03-13 Jutho Haegeman , J. Ignacio Cirac , Tobias J. Osborne , Henri Verschelde , Frank Verstraete

In this paper it is shown that the lattice of C*-covers of an operator algebra does not contain enough information to distinguish operator algebras up to completely isometric isomorphism. In addition, four natural equivalences of the…

Operator Algebras · Mathematics 2025-01-16 Adam Humeniuk , Christopher Ramsey

The classification of mixed-state topological order requires indices that behave monotonically under finite-depth quantum channels. In two dimensions, a braided $C^*$-tensor category, which corresponds to strong symmetry, arises from a…

Mathematical Physics · Physics 2026-01-16 Yoshiko Ogata