Information flow in non-unitary quantum cellular automata

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The information flow in a quantum system is a fundamental feature of its dynamics. An important class of dynamics are quantum cellular automata (QCA), systems with discrete updates invariant in time and space, for which an index theory has been proposed for the quantification of the net flow of quantum information across a boundary. While the index is rigid in the sense of begin invariant under finite-depth local circuits, it is not defined when the system is coupled to an environment, i.e.for non-unitary time evolution of open quantum systems. We propose a new measure of information flow for non-unitary QCA denoted the information current which is not rigid, but can be computed locally based on the matrix-product operator representation of the map.
Original languageEnglish
Article number014
Pages (from-to)1-41
Number of pages41
JournalSciPost Physics
Issue number1
Publication statusPublished - 17 Jan 2024

Bibliographical note

Copyright E. Wagner et al. Published by the SciPost Foundation. Version archived for private and non-commercial use with the permission of the author/s and according to publisher conditions. For further rights please contact the publisher.


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