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Optimal encoding and decoding of a spin direction
2001
Physical Review A. Atomic, Molecular, and Optical Physics
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For a system of N spins 1/2 there are quantum states that can encode a direction in an intrinsic way. Information on this direction can later be decoded by means of a quantum measurement. We present here the optimal encoding and decoding procedure using the fidelity as a figure of merit. We compute the maximal fidelity and prove that it is directly related to the largest zeroes of the Legendre and Jacobi polynomials. We show that this maximal fidelity approaches unity quadratically in 1/N. We
doi:10.1103/physreva.63.052309
fatcat:tm7xzedu75b3zb7puaxjcbslom