The Kirkwood-Dirac representation associated to the Fourier transform for finite abelian groups: positivity

Fuente: arXiv
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Autori principali: De Bièvre, Stephan, Langrenez, Christopher, Radchenko, Danylo
Natura: Preprint
Pubblicazione: 2025
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author De Bièvre, Stephan
Langrenez, Christopher
Radchenko, Danylo
author_facet De Bièvre, Stephan
Langrenez, Christopher
Radchenko, Danylo
contents We construct and study the Kirkwood-Dirac (KD) representations naturally associated to the Fourier transform of finite abelian groups $G$. We identify all pure KD-positive states and all KD-real observables for these KD representations. We provide a necessary and sufficient condition ensuring that all KD-positive states are convex combinations of pure KD-positive states. We prove that for $G=\Z_{d}$, with $d$ a prime power, this condition is satisfied. We provide examples of abelian groups where it is not. In those cases, the convex set of KD-positive states contains states outside the convex hull of the pure KD-positive states.
format Preprint
id arxiv_https___arxiv_org_abs_2501_12252
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle The Kirkwood-Dirac representation associated to the Fourier transform for finite abelian groups: positivity
De Bièvre, Stephan
Langrenez, Christopher
Radchenko, Danylo
Quantum Physics
Mathematical Physics
We construct and study the Kirkwood-Dirac (KD) representations naturally associated to the Fourier transform of finite abelian groups $G$. We identify all pure KD-positive states and all KD-real observables for these KD representations. We provide a necessary and sufficient condition ensuring that all KD-positive states are convex combinations of pure KD-positive states. We prove that for $G=\Z_{d}$, with $d$ a prime power, this condition is satisfied. We provide examples of abelian groups where it is not. In those cases, the convex set of KD-positive states contains states outside the convex hull of the pure KD-positive states.
title The Kirkwood-Dirac representation associated to the Fourier transform for finite abelian groups: positivity
topic Quantum Physics
Mathematical Physics
url https://arxiv.org/abs/2501.12252