On the rank of extremal marginal states

Fuente: arXiv
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Main Authors: Devendra, Repana, Dey, Pankaj, Dey, Santanu
Format: Preprint
Published: 2024
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author Devendra, Repana
Dey, Pankaj
Dey, Santanu
author_facet Devendra, Repana
Dey, Pankaj
Dey, Santanu
contents Let $ρ_1$ and $ρ_2$ be two states on $\mathbb{C}^{d_1}$ and $\mathbb{C}^{d_2}$ respectively. The marginal state space, denoted by $\mathcal{C}(ρ_1,ρ_2)$, is the set of all states $ρ$ on $\mathbb{C}^{d_1}\otimes \mathbb{C}^{d_2}$ with partial traces $ρ_1, ρ_2$. K. R. Parthasarathy established that if $ρ$ is an extreme point of $\mathcal{C}(ρ_1,ρ_2)$, then the rank of $ρ$ does not exceed $\sqrt{d_1^2+d_2^2-1}$. Rudolph posed a question regarding the tightness of this bound. In 2010, Ohno gave an affirmative answer by providing examples in low-dimensional matrix algebras $\mathbb{M}_3$ and $\mathbb{M}_4$. This article aims to provide a positive answer to the Rudolph question in various matrix algebras. Our approaches, to obtain the extremal marginal states with tight upper bound, are based on Choi-Jamiołkowski isomorphism and tensor product of extreme points.
format Preprint
id arxiv_https___arxiv_org_abs_2412_10041
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle On the rank of extremal marginal states
Devendra, Repana
Dey, Pankaj
Dey, Santanu
Operator Algebras
Mathematical Physics
Functional Analysis
46L30, 81P47, 47L07, 46M05, 46N50
Let $ρ_1$ and $ρ_2$ be two states on $\mathbb{C}^{d_1}$ and $\mathbb{C}^{d_2}$ respectively. The marginal state space, denoted by $\mathcal{C}(ρ_1,ρ_2)$, is the set of all states $ρ$ on $\mathbb{C}^{d_1}\otimes \mathbb{C}^{d_2}$ with partial traces $ρ_1, ρ_2$. K. R. Parthasarathy established that if $ρ$ is an extreme point of $\mathcal{C}(ρ_1,ρ_2)$, then the rank of $ρ$ does not exceed $\sqrt{d_1^2+d_2^2-1}$. Rudolph posed a question regarding the tightness of this bound. In 2010, Ohno gave an affirmative answer by providing examples in low-dimensional matrix algebras $\mathbb{M}_3$ and $\mathbb{M}_4$. This article aims to provide a positive answer to the Rudolph question in various matrix algebras. Our approaches, to obtain the extremal marginal states with tight upper bound, are based on Choi-Jamiołkowski isomorphism and tensor product of extreme points.
title On the rank of extremal marginal states
topic Operator Algebras
Mathematical Physics
Functional Analysis
46L30, 81P47, 47L07, 46M05, 46N50
url https://arxiv.org/abs/2412.10041