Entangled quantum states as direction indicators.
We consider the use of N spin-1/2 particles for indicating a direction in space. If N>2, their optimal state is entangled. For large N, the mean square error decreases as N-2 (rather than N-1 for parallel spins).
Peres
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Department of Physics, Technion-Israel Institute of Technology, 32000 Haifa, Israel.
Scudo
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