Quantum metrology: dynamics versus entanglement.
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.
Boixo
Sergio
S
Department of Physics and Astronomy, University of New Mexico, Albuquerque, New Mexico 87131-0001, USA.
Datta
Animesh
A
Davis
Matthew J
MJ
Flammia
Steven T
ST
Shaji
Anil
A
Caves
Carlton M
CM