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.
| Original language | English |
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| Pages (from-to) | 3865-68 |
| Journal | Physical Review Letters |
| Volume | 79 |
| Issue number | 20 |
| DOIs | |
| Publication status | Published - 1997 |