arXiv:1102.0786 · Physical Review A

Optimal phase estimation with arbitrary a priori knowledge

Rafał Demkowicz-Dobrzański

Published Jun 20, 2011• 63 citations

Abstract

The optimal-phase estimation strategy is derived when partial a priori knowledge on the estimated phase is available. The solution is found with the help of the most famous result from the entanglement theory: the positive partial transpose criterion. The structure of the optimal measurements, estimators, and the optimal probe states is analyzed. This Rapid Communication provides a unified framework bridging the gap in the literature on the subject which until now dealt almost exclusively with two extreme cases: almost perfect knowledge (local approach based on Fisher information) and no a priori knowledge (global approach based on covariant measurements). Special attention is paid to a natural a priori probability distribution arising from a diffusion process.

DOI: 10.1103/physreva.83.061802

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