Sergio Boixo

Quantum Metrology: Dynamics versus Entanglement

TitleQuantum Metrology: Dynamics versus Entanglement
Publication TypeJournal Article
Year of Publication2008
AuthorsS. Boixo, A. Datta, M. J. Davis, S. T. Flammia, A. Shaji, and C. M. Caves
JournalPhysical Review Letters

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/n to the 3/2, even when the constituents are initially unentangled. We devise a protocol that achieves the 1/n to the 3/2 scaling without generating any entanglement among the constituents, and we suggest that the protocol might be implemented in a two-component Bose-Einstein condensate.