Improvement of frequency standards with quantum entanglement
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Author
Huelga, S.F.
Macchiavello, C.
Pellizzari, T.
Ekert, A.K.
Plenio, M.B.
Cirac, J.
Attention
2299/1048
Abstract
The optimal precision of frequency measurements in the presence of decoherence is discussed. We analyse different preparations of n two-level systems as well as different measurements procedures. We show that standard Ramsey spec- troscopy on uncorrelated atoms and optimal measurements on maximally entangled states provide the same resolution. The best resolution is achieved using partially entangled preparations with a high degree of symmetry.