SEDLÁK, Michal, Mário ZIMAN, Ondřej PŘIBYLA, Vladimír BUŽEK a Mark HILLERY. Unambiguous coherent state identification: Searching quantum database. Physical Review A. New York: American Physical Society, 2007, Vol. 76, No. 2, s. A022326, 12 s. ISSN 1050-2947. |
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@article{747031, author = {Sedlák, Michal and Ziman, Mário and Přibyla, Ondřej and Bužek, Vladimír and Hillery, Mark}, article_location = {New York}, article_number = {No. 2}, keywords = {quantum information processing; unambiguous state identification; quantum search}, language = {eng}, issn = {1050-2947}, journal = {Physical Review A}, note = {arXiv:0706.1892}, title = {Unambiguous coherent state identification: Searching quantum database}, volume = {Vol. 76}, year = {2007} }
TY - JOUR ID - 747031 AU - Sedlák, Michal - Ziman, Mário - Přibyla, Ondřej - Bužek, Vladimír - Hillery, Mark PY - 2007 TI - Unambiguous coherent state identification: Searching quantum database JF - Physical Review A VL - Vol. 76 IS - No. 2 SP - A022326 EP - A022326 PB - American Physical Society SN - 10502947 N1 - arXiv:0706.1892 KW - quantum information processing KW - unambiguous state identification KW - quantum search N2 - We consider an unambiguous identification of an unknown coherent state with one of two unknown coherent reference states. Specifically, we consider two modes of an electromagnetic field prepared in unknown coherent states |alpha_1> and |alpha_2>, respectively. The third mode is prepared either in the state |alpha_1> or in the state |alpha_2>. The task is to identify (unambiguously) which of the two modes are in the same state. We present a scheme consisting of three beamsplitters capable to perform this task. Although we do not prove the optimality, we show that the performance of the proposed setup is better than the generalization of the optimal measurement known for a finite-dimensional case. We show that a single beamsplitter is capable to perform an unambiguous quantum state comparison for coherent states optimally. Finally we propose an experimental setup consisting of 2N-1 beamsplitters for unambiguous identification among N unknown coherent states. This setup can be considered as a search in a quantum database. The elements of the database are unknown coherent states encoded in different modes of an electromagnetic field. The task is to specify the two modes that are excited in the same, though unknown, coherent state. ER -
SEDLÁK, Michal, Mário ZIMAN, Ondřej PŘIBYLA, Vladimír BUŽEK a Mark HILLERY. Unambiguous coherent state identification: Searching quantum database. \textit{Physical Review A}. New York: American Physical Society, 2007, Vol. 76, No. 2, s.~A022326, 12 s. ISSN~1050-2947.
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