A class of Schwarz qubit maps with diagonal unitary and orthogonal symmetries

Fuente: arXiv
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Main Authors: Chruściński, Dariusz, Bhattacharya, Bihalan
Format: Preprint
Published: 2024
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author Chruściński, Dariusz
Bhattacharya, Bihalan
author_facet Chruściński, Dariusz
Bhattacharya, Bihalan
contents A class of unital qubit maps displaying diagonal unitary and orthogonal symmetries is analyzed. Such maps already found a lot applications in quantum information theory. We provide a complete characterization of this class of maps showing intricate relation between positivity, operator Schwarz inequality, and complete positivity. Finally, it is shown how to generalize the entire picture beyond unital case (so called generalized Schwarz maps). Interestingly, the first example of Schwarz but not completely positive map found by Choi belongs to our class. As a case study we provide a full characterization of Pauli maps. Our analysis leads to generalization of seminal Fujiwara-Algoet conditions for Pauli quantum channels.
format Preprint
id arxiv_https___arxiv_org_abs_2404_10895
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle A class of Schwarz qubit maps with diagonal unitary and orthogonal symmetries
Chruściński, Dariusz
Bhattacharya, Bihalan
Quantum Physics
Mathematical Physics
A class of unital qubit maps displaying diagonal unitary and orthogonal symmetries is analyzed. Such maps already found a lot applications in quantum information theory. We provide a complete characterization of this class of maps showing intricate relation between positivity, operator Schwarz inequality, and complete positivity. Finally, it is shown how to generalize the entire picture beyond unital case (so called generalized Schwarz maps). Interestingly, the first example of Schwarz but not completely positive map found by Choi belongs to our class. As a case study we provide a full characterization of Pauli maps. Our analysis leads to generalization of seminal Fujiwara-Algoet conditions for Pauli quantum channels.
title A class of Schwarz qubit maps with diagonal unitary and orthogonal symmetries
topic Quantum Physics
Mathematical Physics
url https://arxiv.org/abs/2404.10895