Phase estimation withouta prioriphase knowledge in the presence of loss
Jan Kołodyński, Rafał Demkowicz-Dobrzański · Physical Review A · 2010
We find the optimal scheme for quantum phase estimation in the presence of loss when no a priori knowledge on the estimated phase is available. We prove analytically an explicit lower bound on estimation uncertainty, which shows that, as a function of the number of probes, quantum precision enhancement amounts at most to a constant factor improvement over classical strategies.