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arXiv:0805.2180 · Physical Review Letters

Quantum Metrology: Dynamics versus Entanglement

Sergio Boixo, Animesh Datta, Matthew J. Davis, Steven T. Flammia, Anil Shaji, Carlton M. Caves

Published Jul 24, 2008• 228 citations
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Abstract

A parameter whose coupling to a quantum probe of n constituents includes all two-body interactions between the constituents can be measured with an uncertainty that scales as 1/n3/2, even when the constituents are initially unentangled. We devise a protocol that achieves the 1/n3/2 scaling without generating any entanglement among the constituents, and we suggest that the protocol might be implemented in a two-component Bose-Einstein condensate.

DOI
10.1103/physrevlett.101.040403

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