Exploring boundaries of quantum convex structures: special role of unitary processes

PUCHAŁA, Zbigniew, Anna JENCOVA, Michal SEDLÁK and Mário ZIMAN. Exploring boundaries of quantum convex structures: special role of unitary processes. Phys. Rev. A. USA: The American Phys. Society, 2015, vol. 92, No 1, p. 012304-12310. ISSN 1050-2947. Available from: https://dx.doi.org/10.1103/PhysRevA.92.012304.

Basic information

• Original name: Exploring boundaries of quantum convex structures: special role of unitary processes
• Authors: PUCHAŁA, Zbigniew (616 Poland), Anna JENCOVA (703 Slovakia), Michal SEDLÁK (703 Slovakia) and Mário ZIMAN (703 Slovakia, guarantor, belonging to the institution).
• Edition: Phys. Rev. A, USA, The American Phys. Society, 2015, 1050-2947.

Other information

• Original language: English
• Type of outcome: Article in a journal
• Field of Study: 10301 Atomic, molecular and chemical physics
• Country of publisher: United States of America
• Confidentiality degree: is not subject to a state or trade secret
• WWW: URL
• Impact factor: Impact factor: 2.808 in 2014
• RIV identification code: RIV/00216224:14330/15:00081695
• Organization unit: Faculty of Informatics
• Doi: http://dx.doi.org/10.1103/PhysRevA.92.012304
• UT WoS: 000357260500003
• Keywords in English: quantum structure - quantum measurement - quantum information
• Tags: International impact, Reviewed

Abstract

We address the question of finding the most unbalanced convex decompositions into boundary elements (so-called boundariness) for sets of quantum states, observables, and channels. We show that in general convex sets the boundariness essentially coincides with the question of the most distinguishable element, thus providing an operational meaning for this concept. Unexpectedly, we discovered that for any interior point of the set of channels the most unbalanced decomposition necessarily contains a unitary channel. In other words, for any given channel the most distinguishable one is some unitary channel. Further, we prove that boundariness is submultiplicative under the composition of systems and explicitly evaluate its maximal value that is attained only for the most mixed elements of the considered sets.

Links

• GAP202/12/1142, research and development project: Name: Slabé zdroje entanglementu a náhodnosti

Investor: Czech Science Foundation