Decoherence and Quantum Error Correction in Frequency Standards
Chiara Macchiavello, Susana F. Huelga, J. I. Cirac, ARTUR K. EKERT, Martin Bodo Plenio · Kluwer Academic Publishers eBooks · 2005
The precision of frequency measurements performed on trapped ions in the presence of decoherence is analysed. In particular, standard Ramsey spectroscopy on uucorrelated ions and optimal measurements on maximally entangled states are proved to lead to the same resolution, while the best precision is achieved using partially entangled preparations. The use of symrnetrisation procedures is proposed and it is shown how this allows to overcome even the optimal precision achievable when both the initial preparation and the final measurement are optimized. These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.