Distinguishing classically indistinguishable states and channels
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.
- Publication:
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Journal of Physics A Mathematical General
- Pub Date:
- November 2019
- DOI:
- 10.1088/1751-8121/ab30f7
- arXiv:
- arXiv:1812.09083
- Bibcode:
- 2019JPhA...52U5303K
- Keywords:
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- distinguishability;
- quantum channels;
- coherence;
- decoherence;
- Quantum Physics
- E-Print:
- 22 pages, 8 figures. Published version