Quantum correlation measure in arbitrary bipartite systems

Quantum correlation with a novel definition is presented for an arbitrary bipartite quantum state in terms of the skew information of the complete set of rank-one orthogonal projectors. This definition not only inherits the good properties of skew information including the contractivity, but also shows a powerful analytic computability for a large range of states. In addition, the measure for a general state can be easily numerically obtained by the well-developed technique of the approximate joint diagonalization. As a comparison, we give both the analytic and the numerical quantum correlation for many high-dimensional states. The relation between our measure and quantum metrology is also analyzed.