Quantum advantage in postselected metrology

• Published in: Nature communications Vol. 11; no. 1; p. 3775
• Main Authors: Arvidsson-Shukur, David R M, Yunger Halpern, Nicole, Lepage, Hugo V, Lasek, Aleksander A, Barnes, Crispin H W, Lloyd, Seth
• Format: Journal Article
• Language: English
• Published: England Nature Publishing Group 29.07.2020; Nature Publishing Group UK; Nature Portfolio
• Subjects: Commuting; Experiments; Fisher information; Mathematical analysis; Metrology; Parameter estimation; Probability distribution

In every parameter-estimation experiment, the final measurement or the postprocessing incurs a cost. Postselection can improve the rate of Fisher information (the average information learned about an unknown parameter from a trial) to cost. We show that this improvement stems from the negativity of...