An optimal measurement strategy to beat the quantum uncertainty in correlated system

Abstract

Uncertainty principle is an inherent nature of quantum system that undermines the precise measurement of incompatible observables and hence the applications of quantum theory. Entanglement, another unique feature of quantum physics, was found may help to reduce the quantum uncertainty. In this paper, we propose a practical method to reduce the one party measurement uncertainty by determining the measurement on the other party of an entangled bipartite system. In light of this method, a family of conditional majorization uncertainty relations in the presence of quantum memory is constructed, which is applicable to arbitrary number of observables. The new family of uncertainty relations implies sophisticated structures of quantum uncertainty and nonlocality, that were usually studied by using scalar measures. Applications to reduce the local uncertainty and to witness quantum nonlocalities are also presented.