Home › Content

Phase estimation without a priori phase knowledge in the presence of loss

Thu, 2011-02-17 13:00 - Q-Essence Coordinator
Printer-friendly versionSend by emailPDF version
Date: 
2010-11-04
Reference: 

Jan Kołodyński and Rafał Demkowicz-Dobrzański
Phys. Rev. A 82, 053804 (2010)
http://link.aps.org/doi/10.1103/PhysRevA.82.053804

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.