English
Related papers

Related papers: De Finetti theorem on the CAR algebra

200 papers

We analyze a natural C*-algebraic definition of G-quasi-invariant states for the automorphic action of a compact group G. We prove that, given a G-quasi-invariant state with central support, when the action of the group G commutes with the…

Operator Algebras · Mathematics 2025-07-29 Maria Elena Griseta

We prove that the automorphism group of a Cuntz algebra of finite order acts transitively on the set of pure states which are invariant under some gauge actions (which may depend on the states). The question of whether any pure state is…

Operator Algebras · Mathematics 2007-05-23 Ola Bratteli , Akitaka Kishimoto

We consider quasifree ground states of Araki's self-dual CAR algebra from the viewpoint of index theory and symmetry protected topological (SPT) phases. We first review how Clifford module indices characterise a topological obstruction to…

Mathematical Physics · Physics 2022-02-02 Chris Bourne

We prove a generalization of the quantum de Finetti theorem when the local space is an infinite-dimensional Fock space. In particular, instead of considering the action of the permutation group on $n$ copies of that space, we consider the…

Quantum Physics · Physics 2022-07-13 Anthony Leverrier

The classical de Finetti Theorem classifies the $\mathrm{Sym}(\mathbb N)$-invariant probability measures on $[0,1]^{\mathbb N}$. More precisely it states that those invariant measures are combinations of measures of the form…

Probability · Mathematics 2024-11-05 Colin Jahel , Pierre Perruchaud

De Finetti theorems show how sufficiently exchangeable states are well-approximated by convex combinations of i.i.d. states. Recently, it was shown that in many quantum information applications a more relaxed de Finetti reduction (i.e. only…

Quantum Physics · Physics 2020-01-27 Cécilia Lancien , Andreas Winter

Given an abelian group G endowed with a T-pre-symplectic form, we assign to it a symplectic twisted group *-algebra W_G and then we provide criteria for the uniqueness of states invariant under the ergodic action of the symplectic group of…

Operator Algebras · Mathematics 2022-02-24 Federico Bambozzi , Simone Murro

We prove several de Finetti theorems for the unitary dual group, also called the Brown algebra. Firstly, we provide a finite de Finetti theorem characterizing $R$-diagonal elements with an identical distribution. This is surprising, since…

Operator Algebras · Mathematics 2022-09-14 Isabelle Baraquin , Guillaume Cébron , Uwe Franz , Laura Maassen , Moritz Weber

We prove general de Finetti type theorems for classical and free independence. The de Finetti type theorems work for all non-easy quantum groups, which generalize a recent work of Banica, Curran and Speicher. We determine maximal…

Operator Algebras · Mathematics 2019-04-26 Weihua Liu

We prove a version of the quantum de Finetti theorem: permutation-invariant quantum states are well approximated as a probabilistic mixture of multi-fold product states. The approximation is measured by distinguishability under fully…

Quantum Physics · Physics 2015-04-29 Ke Li , Graeme Smith

We show that the space of tracial quantum symmetric states of an arbitrary unital C*-algebra is a Choquet simplex and is a face of the tracial state space of the universal unital C*-algebra free product of A with itself infinitely many…

Operator Algebras · Mathematics 2014-10-29 Yoann Dabrowski , Kenneth J. Dykema , Kunal Mukherjee

We prove a new kind of quantum de Finetti theorem for representations of the unitary group U(d). Consider a pure state that lies in the irreducible representation U_{mu+nu} for Young diagrams mu and nu. U_{mu+nu} is contained in the tensor…

Quantum Physics · Physics 2009-11-13 Matthias Christandl , Robert Koenig , Graeme Mitchison , Renato Renner

We establish a dilation-theoretic characterization of the Choquet order on the space of measures on a compact convex set using ideas from the theory of operator algebras. This yields an extension of Cartier's dilation theorem to the…

Operator Algebras · Mathematics 2021-05-03 Kenneth R. Davidson , Matthew Kennedy

We show that the classical de Finetti theorem has a canonical noncommutative counterpart if we strengthen `exchangeability' (i.e., invariance of the joint distribution of the random variables under the action of the permutation group) to…

Operator Algebras · Mathematics 2009-11-13 Claus Köstler , Roland Speicher

Let $G$ be a countable discrete amenable group, and $\Lambda$ be a strongly connected finite $k$-graph. If $(G,\Lambda)$ is a pseudo free and locally faithful self-similar action which satisfies the finite-state condition, then the…

Operator Algebras · Mathematics 2018-05-23 Hui Li , Dilian Yang

Let $F$ be a non-discrete non-Archimedean locally compact field such that the characteristic $\mathrm{ch}(F)\ne 2$ and let $\mathcal{O}_F$ be the ring of integers in $F$. The main results of this paper are Theorem 1.2 that classifies…

Dynamical Systems · Mathematics 2016-06-03 Yanqi Qiu

We prove automorphic equivalence within gapped phases of infinitely extended lattice fermion systems (as well as spin systems) with super-polynomially decaying interactions. As a simple application, we prove a version of Goldstone's theorem…

Mathematical Physics · Physics 2025-08-08 Lennart Becker , Stefan Teufel , Marius Wesle

A continuous groupoid homomorphism $c$ on a locally compact second countable Hausdorff \'etale groupoid $\mathcal{G}$ gives rise to a $C^{*}$-dynamical system in which every $\beta$-KMS state can be associated to a $e^{-\beta…

Operator Algebras · Mathematics 2018-10-17 Johannes Christensen

The aim of this paper is to prove ergodic decomposition theorems for probability measures quasi-invariant under Borel actions of inductively compact groups (Theorem 1) as well as for sigma-finite invariant measures (Corollary 1). For…

Dynamical Systems · Mathematics 2014-07-28 Alexander I. Bufetov

{\abstract{\textwidth=4,5 in} A discrete time process, with law $\mu$, is quasi-exchangeable if for any finite permutation $\sigma$ of time indices, the law $\mu_\sigma$ of the resulting process is equivalent to $\mu$. For a…

Dynamical Systems · Mathematics 2020-07-02 Doureid Hamdan