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Locating Overlap Information in Quantum Systems

Andreas Albrecht
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Abstract

When discussing the black hole information problem the term ``information flow'' is frequently used in a rather loose fashion. In this article I attempt to make this notion more concrete. I consider a Hilbert space which is constructed as a tensor product of two subspaces (representing for example inside and outside the black hole). I discuss how the system has the capacity to contain information which is in NEITHER of the subspaces. I attempt to quantify the amount of information located in each of the two subspaces, and elsewhere, and analyze the extent to which unitary evolution can correspond to ``information flow''. I define the notion of ``overlap information'' which appears to be well suited to the problem.

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Andreas Albrecht. 1994-04-12. Locating Overlap Information in Quantum Systems. https://doi.org/10.1103/physrevd.50.2744

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