Quantifying information flow in quantum processes - UTU Research Portal

A1 Refereed original research article in a scientific journal

Quantifying information flow in quantum processes

Authors: Santos, Leonardo S. V.; Xu, Zhen-Peng; Piilo, Jyrki; Guehne, Otfried

Publisher: American Physical Society (APS)

Publishing place: COLLEGE PK

Publication year: 2025

Journal: Physical Review A

Journal name in source: Physical Review A

Journal acronym: PHYS REV A

Article number: 022201

Volume: 112

Issue: 2

Number of pages: 12

ISSN: 2469-9926

eISSN: 2469-9934

DOI: https://doi.org/10.1103/5211-h7g2

Web address : https://doi.org/10.1103/5211-h7g2

Self-archived copy’s web address: https://research.utu.fi/converis/portal/detail/Publication/499702804

Abstract

We present a framework for quantifying information flow within general quantum processes. For this purpose, we introduce the signaling power of quantum channels and discuss its relevant operational properties. This function supports extensions to higher-order maps, enabling the evaluation of information flow in general quantum causal networks and processes with indefinite causal order. Furthermore, our results offer a rigorous approach to information dynamics in open systems that applies also in the presence of initial system-environment correlations, and allows for the distinction between classical and quantum information backflow.

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Funding information in the publication:
We thank Roope Uola and Kimmo Luoma for discussions and Dariusz Chruscinski and Simon Milz for key remarks. This work was supported by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation, Projects No. 447948357 and 440958198) , the Sino-German Center for Research Promotion (Project No. M-0294) , and the German Ministry of Education and Research (Project QuKuK, BMBF Grant No. 16KIS1618K) . Z.-P.X. acknowledges support from National Natural Science Foundation of China (Grant No. 12305007) and Anhui Provincial Natural Science Foundation (Grant No. 2308085QA29) . L.S.V.S. acknowledges support from the House of Young Talents of the University of Siegen.