Identification and Distance Measures of Measurement Apparatus
Zhengfeng Ji, Yuan Feng, Runyao Duan, Mingsheng Ying · Physical Review Letters · 2006
We propose simple schemes that can perfectly identify projective measurement apparatuses secretly chosen from a finite set. Entanglement is used in these schemes both to make possible the perfect identification and to improve the efficiency significantly. Based on these results, a brief discussion on the problem of how to appropriately define distance measures of measurements is also provided.