Unambiguous comparison of unitary channels
| Authors | |
|---|---|
| Year of publication | 2009 |
| Type | Article in Periodical |
| Magazine / Source | Physical Review A |
| MU Faculty or unit | |
| Citation | |
| Web | http://arxiv.org/abs/0809.4401 |
| Field | Informatics |
| Keywords | Quantum information processing; unitary channels |
| Description | We address the problem of unambiguous comparison of a pair of unknown qudit unitary channels. Using the framework of process positive operator valued measures (PPOVM) we characterize all solutions and identify the optimal ones. We prove that the entanglement is the key ingredient in designing the optimal experiment for comparison of unitary channels. Without entanglement the optimality can not be achieved. The proposed scheme is also experimentally feasible. |
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