Comment on “Saturating quantum advantages in postselected metrology with the positive Kirkwood-Dirac distribution”
David R. M. Arvidsson-Shukur, C. H. W. Barnes, Hugo Vincent Lepage, Seth Lloyd, Noah Lupu-Gladstein, Wilfred Salmon, Flavio Salvati · Physical Review A · 2024
In a recent paper [Das, Modak, and Bera, Phys. Rev. A 107, 042413 (2023)], Das et al. claim that Kirkwood-Dirac negativity is not required to achieve anomalous values of the quantum Fisher information encoded in postselected (filtered) particles. We argue that this claim is wrong. Further, we show that the quantum Fisher information in optimal postselected metrology is directly proportional to the total Kirkwood-Dirac nonclassicality.