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Main Authors: Teixidó-Bonfill, Adam, Schindler, Joseph, Šafránek, Dominik
Format: Preprint
Published: 2023
Subjects:
Online Access:https://arxiv.org/abs/2310.14086
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author Teixidó-Bonfill, Adam
Schindler, Joseph
Šafránek, Dominik
author_facet Teixidó-Bonfill, Adam
Schindler, Joseph
Šafránek, Dominik
contents We investigate four partial orderings on the space of quantum measurements (i.e on POVMs or positive operator valued measures), describing four notions of coarse/fine-ness of measurement. These are the partial orderings induced by: (1) classical post-processing, (2) measured relative entropy, (3) observational entropy, and (4) linear relation of POVMs. The orderings form a hierarchy of implication, where e.g. post-processing relation implies all the others. We show that this hierarchy is strict for general POVMs, with examples showing that all four orderings are strictly inequivalent. Restricted to projective measurements, all are equivalent. Finally we show that observational entropy equality $S_M = S_N$ (for all $ρ$) holds if and only if $M \equiv N$ are post-processing equivalent, which shows that the first three orderings induce identical equivalence classes.
format Preprint
id arxiv_https___arxiv_org_abs_2310_14086
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Entropic partial orderings of quantum measurements
Teixidó-Bonfill, Adam
Schindler, Joseph
Šafránek, Dominik
Quantum Physics
Mathematical Physics
We investigate four partial orderings on the space of quantum measurements (i.e on POVMs or positive operator valued measures), describing four notions of coarse/fine-ness of measurement. These are the partial orderings induced by: (1) classical post-processing, (2) measured relative entropy, (3) observational entropy, and (4) linear relation of POVMs. The orderings form a hierarchy of implication, where e.g. post-processing relation implies all the others. We show that this hierarchy is strict for general POVMs, with examples showing that all four orderings are strictly inequivalent. Restricted to projective measurements, all are equivalent. Finally we show that observational entropy equality $S_M = S_N$ (for all $ρ$) holds if and only if $M \equiv N$ are post-processing equivalent, which shows that the first three orderings induce identical equivalence classes.
title Entropic partial orderings of quantum measurements
topic Quantum Physics
Mathematical Physics
url https://arxiv.org/abs/2310.14086