A quantum measurement can be described by a set of matrices, one for each possible outcome, which represents the probability operator-valued measure (POVM) of the sensor. Ecient protocols of POVM extraction for arbitrary sensors are required. We present the rst experimental POVM reconstruction that takes explicit advantage of a quantum resource, i.e. nonclassical correlations with an ancillary state. POVM of a photon-number-resolving detector is reconstructed by using strong quantum correlations of twin-beams generated by parametric downconversion. Our reconstruction method is more statistically robust than POVM reconstruction methods that use classical input states.
- OGGISCIENZA, 14 agosto 2012, "Meccanica quantistica da laboratorio" Simona Cerrato