Metrology-induced quantum nonlocality

Abstract

Nonlocality and quantum metrology are two fundamental ingredients in quantum physics. Measuring and characterizing nonlocal quantum correlations existing in any quantum state for the purposes of quantum information processing applications should receive therefore much interest. This work introduces a metrological-based approach for quantifying quantum nonlocality as a form of correlation. The scheme can be executed by exploiting the quantum estimation theory to define metrology-induced quantum nonlocality (MIQN) as the maximal increment of quantum Fisher information. MIQN can be done by acting a local commuting observable on one of the parts of a quantum bipartite probe state to estimate a parameter encoded by a local rotation. For the \(2\times d\)-dimensional mixed states, the closed form of MIQN is evaluated. Furthermore, we proved that the proposed quantifier fulfills all the criteria of a well-defined quantum correlations measure.