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arXiv · 1812.09083

Distinguishing classically indistinguishable states and channels

Kamil Korzekwa·Stanisław Czachórski·Zbigniew Puchała·Karol Życzkowski
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Abstract

We investigate an original family of quantum distinguishability problems, where the goal is to perfectly distinguish between $M$ quantum states that become identical under a completely decohering map. Similarly, we study distinguishability of $M$ quantum channels that cannot be distinguished when one is restricted to decohered input and output states. The studied problems arise naturally in the presence of a superselection rule, allow one to quantify the amount of information that can be encoded in phase degrees of freedom (coherences), and are related to time-energy uncertainty relation. We present a collection of results on both necessary and sufficient conditions for the existence of $M$ perfectly distinguishable states (channels) that are classically indistinguishable.

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Kamil Korzekwa, Stanisław Czachórski, Zbigniew Puchała, Karol Życzkowski. 2018-12-21. Distinguishing classically indistinguishable states and channels. https://doi.org/10.1088/1751-8121/ab30f7

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