1205.0798 (G. Brida et al.)

Enhanced ancilla-assisted calibration of a measuring apparatus    [PDF]

G. Brida, L. Ciavarella, I. P. Degiovanni, M. Genovese, A. Migdall, M. G. Mingolla, M. G. A. Paris, F. Piacentini, S. V. Polyakov

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. Efficient protocols of POVM extraction for arbitrary sensors are required. We present the first 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.

View original: http://arxiv.org/abs/1205.0798