On Dynamical Measures of Quantum Information
Name
entropy-27-00331.pdf
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5.72 MB
Format
Adobe PDF
Checksum (MD5)
5db616ab9a1466c87f008142c60f9e65
Author(s)
Fullwood, James
Parzygnat, Arthur J.
Date Issued
March 21, 2025
Journal
Entropy
Publisher
Multidisciplinary Digital Publishing Institute
Citation
Fullwood, J.; Parzygnat, A.J. On Dynamical Measures of Quantum Information. Entropy 2025, 27, 331.
Version
Final published version
Abstract
In this work, we use the theory of quantum states over time to define joint entropy for timelike-separated quantum systems. For timelike-separated systems that admit a dual description as being spacelike-separated, our notion of entropy recovers the usual von Neumann entropy for bipartite quantum states and thus may be viewed as a spacetime generalization of von Neumann entropy. Such an entropy is then used to define dynamical extensions of quantum joint entropy, quantum conditional entropy, and quantum mutual information for systems separated by the action of a quantum channel. We provide an in-depth mathematical analysis of such information measures and the properties they satisfy. We also use such a dynamical formulation of entropy to quantify the information loss/gain associated with the dynamical evolution of quantum systems, which enables us to formulate a precise notion of information conservation for quantum processes. Finally, we show how our dynamical entropy admits an operational interpretation in terms of quantifying the amount of state disturbance associated with a positive operator- valued measurement.
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Creative Commons Attribution
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DOI of Published Version
http://dx.doi.org/10.3390/e27040331
