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Communication of Spin Directions with Product States and Finite Measurements

E. Bagan·M. Baig·R. Munoz-Tapia
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Abstract

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 behaviour 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.

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E. Bagan, M. Baig, R. Munoz-Tapia. 2001-04-25. Communication of Spin Directions with Product States and Finite Measurements. https://doi.org/10.1103/physreva.64.022305

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