A Hierarchy of Deviation from Complete Positivity and Optimal Entanglement Witnesses

Fuente: arXiv
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Autore principale: Kian, Mohsen
Natura: Preprint
Pubblicazione: 2025
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author Kian, Mohsen
author_facet Kian, Mohsen
contents We introduce the \emph{CP-distance} to quantify the deviation of Hermitian linear maps from complete positivity, defined as the minimal depolarizing noise required to render a map completely positive. We derive a closed spectral formula for this distance and extend the framework to \emph{directional robustness} against arbitrary completely positive maps, establishing stability and tensor-product properties. Expanding this to the intermediate cones of $k$-positive maps, we introduce a \emph{hierarchy of deviation}, $d_k(Φ)$. We derive a spectral formula for $d_k$ based on entanglement depth and demonstrate that it serves as an optimal threshold for certifying Schmidt numbers, allowing for the universal construction of dimension-sensitive entanglement witnesses.
format Preprint
id arxiv_https___arxiv_org_abs_2506_03773
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle A Hierarchy of Deviation from Complete Positivity and Optimal Entanglement Witnesses
Kian, Mohsen
Quantum Physics
Functional Analysis
We introduce the \emph{CP-distance} to quantify the deviation of Hermitian linear maps from complete positivity, defined as the minimal depolarizing noise required to render a map completely positive. We derive a closed spectral formula for this distance and extend the framework to \emph{directional robustness} against arbitrary completely positive maps, establishing stability and tensor-product properties. Expanding this to the intermediate cones of $k$-positive maps, we introduce a \emph{hierarchy of deviation}, $d_k(Φ)$. We derive a spectral formula for $d_k$ based on entanglement depth and demonstrate that it serves as an optimal threshold for certifying Schmidt numbers, allowing for the universal construction of dimension-sensitive entanglement witnesses.
title A Hierarchy of Deviation from Complete Positivity and Optimal Entanglement Witnesses
topic Quantum Physics
Functional Analysis
url https://arxiv.org/abs/2506.03773