Uniqueness of purifications is equivalent to Haag duality

Fuente: arXiv
Saved in:
Bibliographic Details
Main Authors: van Luijk, Lauritz, Stottmeister, Alexander, Wilming, Henrik
Format: Preprint
Published: 2025
Subjects:
Online Access:
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866908864057704448
author van Luijk, Lauritz
Stottmeister, Alexander
Wilming, Henrik
author_facet van Luijk, Lauritz
Stottmeister, Alexander
Wilming, Henrik
contents The uniqueness of purifications of quantum states on a system $A$ up to local unitary transformations on a purifying system $B$ is central to quantum information theory. We show that, if the two systems are modelled by commuting von Neumann algebras $M_A$ and $M_B$ on a Hilbert space $\mathcal H$, then uniqueness of purifications is equivalent to Haag duality $M_A = M_B'$. In particular, the uniqueness of purifications can fail in systems with infinitely many degrees of freedom -- even when $M_A$ and $M_B$ are commuting factors that jointly generate $B(\mathcal H)$ and hence allow for local tomography of all density matrices on $\mathcal H$.
format Preprint
id arxiv_https___arxiv_org_abs_2509_12911
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Uniqueness of purifications is equivalent to Haag duality
van Luijk, Lauritz
Stottmeister, Alexander
Wilming, Henrik
Quantum Physics
Mathematical Physics
Operator Algebras
The uniqueness of purifications of quantum states on a system $A$ up to local unitary transformations on a purifying system $B$ is central to quantum information theory. We show that, if the two systems are modelled by commuting von Neumann algebras $M_A$ and $M_B$ on a Hilbert space $\mathcal H$, then uniqueness of purifications is equivalent to Haag duality $M_A = M_B'$. In particular, the uniqueness of purifications can fail in systems with infinitely many degrees of freedom -- even when $M_A$ and $M_B$ are commuting factors that jointly generate $B(\mathcal H)$ and hence allow for local tomography of all density matrices on $\mathcal H$.
title Uniqueness of purifications is equivalent to Haag duality
topic Quantum Physics
Mathematical Physics
Operator Algebras
url https://arxiv.org/abs/2509.12911