On the independence of local algebras

Paweł Kruszyński, Kazimierz Napiórkowski

Claudio D’Antoni

Péter Vrana

We show that the inverse limit of the graded algebras of local unitary invariant polynomials of finite dimensional k-partite quantum systems is free, and give an algebraically independent generating set. The number of degree 2d invariants in the generating set is equal to the number of conjugacy classes of index d subgroups of a free group on k-1 generators.

Fabio Benatti, Roberto Floreanini B

In the case of systems composed of identical particles, a typical instance in quantum statistical mechanics, the standard approach to separability and entanglement ought to be reformulated and rephrased in terms of correlations between operators from subalgebras localized in spatially disjoint regions. While this algebraic approach is straightforward for bosons, in the case of fermions it is subtler since one has to distinguish between micro-causality, that is the anti-commutativity of the basic creation and annihilation operators, and algebraic independence that is the commutativity of local observables. We argue that a consistent algebraic formulation of separability and entanglement should be compatible with micro-causality rather than with algebraic independence.

Yuichiro Kitajima

In algebraic quantum field theory, some von Neumann algebra is associated with any finite open set in Minkowski space-time. Such a von Neumann algebra is called a local algebra. Let V1 and V2 be two spacelikely separated spacetime regions and let N(V1) and N(V2) be local algebras associated with V1 and V2 respectively. In the present paper it is shown that N(V1) and N(V2) are logically independent if and only if any correlation between projections of N(V1) and N(V2) has a Reichenbach's pre-common cause explanation.

Stanisław Goldstein, Andrzej Łuczak, Ivan F. Wilde