Communication of spin directions with product states and finite measurements -: art. no. 022305

被引:27
作者
Bagan, E
Baig, M
Muñoz-Tapia, R
机构
[1] Univ Autonoma Barcelona, Fis Teor Grp, Bellaterra 08193, Spain
[2] Univ Autonoma Barcelona, IFAE, Fac Ciencies, Bellaterra 08193, Spain
来源
PHYSICAL REVIEW A | 2001年 / 64卷 / 02期
关键词
D O I
10.1103/PhysRevA.64.022305
中图分类号
O43 [光学];
学科分类号
070207 ; 0803 ;
摘要
Total spin eigenstates can be used to intrinsically encode a direction, which can later be decoded by means of a quantum measurement. We study the optimal strategy that can be adopted if, as is likely in practical applications, only product states of N spins are available. We obtain the asymptotic behavior of the average fidelity, which provides a proof that the optimal states must be entangled. We also give a prescription for constructing finite measurements for general encoding eigenstates.
引用
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页数:4
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