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arXiv · 1305.0932

Negative Conditional Entropy of Post-Selected States

Sina Salek·Roman Schubert·Karoline Wiesner
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Abstract

We define a quantum entropy conditioned on post-selection which has the von Neumann entropy of pure states as a special case. This conditional entropy can take negative values which is consistent with part of a quantum system containing less information than the whole which can be in a pure state. The definition is based on generalised density operators for postselected ensembles. The corresponding density operators are consistent with the quantum generalisation of classical conditional probabilities following Dirac s formalism of quasiprobability distributions.

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Sina Salek, Roman Schubert, Karoline Wiesner. 2014-04-08. Negative Conditional Entropy of Post-Selected States. https://doi.org/10.1103/physreva.90.022116

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