Continuity bounds on observational entropy and measured relative entropies

Fuente: arXiv
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Autores principales: Schindler, Joseph, Winter, Andreas
Formato: Preprint
Publicado: 2023
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author Schindler, Joseph
Winter, Andreas
author_facet Schindler, Joseph
Winter, Andreas
contents We derive a measurement-independent asymptotic continuity bound on the observational entropy for general POVM measurements, making essential use of its property of bounded concavity. The same insight is used to obtain continuity bounds for other entropic quantities, including the measured relative entropy distance to a convex a set of states under a general set of measurements. As a special case, we define and study conditional observational entropy, which is an observational entropy in one (measured) subsystem conditioned on the quantum state in another (unmeasured) subsystem. We also study continuity of relative entropy with respect to a jointly applied channel, finding that observational entropy is uniformly continuous as a function of the measurement. But we show by means of an example that this continuity under measurements cannot have the form of a concrete asymptotic bound.
format Preprint
id arxiv_https___arxiv_org_abs_2302_00400
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Continuity bounds on observational entropy and measured relative entropies
Schindler, Joseph
Winter, Andreas
Quantum Physics
Mathematical Physics
We derive a measurement-independent asymptotic continuity bound on the observational entropy for general POVM measurements, making essential use of its property of bounded concavity. The same insight is used to obtain continuity bounds for other entropic quantities, including the measured relative entropy distance to a convex a set of states under a general set of measurements. As a special case, we define and study conditional observational entropy, which is an observational entropy in one (measured) subsystem conditioned on the quantum state in another (unmeasured) subsystem. We also study continuity of relative entropy with respect to a jointly applied channel, finding that observational entropy is uniformly continuous as a function of the measurement. But we show by means of an example that this continuity under measurements cannot have the form of a concrete asymptotic bound.
title Continuity bounds on observational entropy and measured relative entropies
topic Quantum Physics
Mathematical Physics
url https://arxiv.org/abs/2302.00400