Classicality from quantumness revealed by disturbance-free measurement

Sang Min Lee, Minsu Kim, Heonoh Kim, Han Seb Moon, Sang Wook Kim

Published 2017-10-11Version 1

We propose an asymptotic disturbance-free measurement using the so-called weak-value scheme,where the weakly measured quantum system is measured for a second time, to confirm that it is disturbance-free; moreover, the probability of obtaining the non-disturbed state must approach one. We show that the weak-measurement outcomes of the Bell state post-selected in this manner exhibit classical behavior in the sense that they satisfy the Clauser-Horne-Shimony-Holt inequality. However, the inequality is violated if all outcomes without post-selection are considered. We experimentally confirm our idea by performing joint weak measurement of polarization-entangled photon-pairs and subsequent fiber-based Bell-state measurement.