Distinguishing classically indistinguishable states and channels
| Author | Korzekwa K.; Czachórski S.; Puchała Z.; Życzkowski K. |
|---|---|
| Title | Distinguishing classically indistinguishable states and channels |
| Journal | Journal of Physics A: Mathematical and Theoretical |
| Year | 2019 |
| Status | Published |
| Volume | 52 |
| Pages | 475303 |
| URL | https://arxiv.org/abs/1812.09083 |
| Abstract | <p>We investigate an original family of quantum distinguishability problems, where the goal is to perfectly distinguish between <span style="font-size:129%"><em>M</em></span> quantum states that become identical under a completely decohering map. Similarly, we study distinguishability of <span style="font-size:129%"><em>M</em></span> 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 <span style="font-size:129%"><em>M</em></span> perfectly distinguishable states (channels) that are classically indistinguishable.</p> |