Quantifying nonclassical correlation via the generalized Wigner-Yanase skew information

Abstract

Nonclassical correlation is an important concept in quantum information theory, referring to a special type of correlation that exists between quantum systems, which surpasses the scope of classical physics. In this paper, we introduce the concept of a family of information with important properties, namely the generalized Wigner-Yanase skew information, of which the famous quantum Fisher information and Wigner-Yanase skew information are special cases.We classify the local observables in the generalized Wigner-Yanase skew information into two categories (i.e., orthonormal bases and a Hermitian operator with a fixed nondegenerate spectrum), and based on this, we propose two different forms of indicators to quantify nonclassical correlations of bipartite quantum states. We have not only investigated some important properties of these two kinds of indicators but also illustrated through specific examples that they can indeed capture some nonclassical correlations. Furthermore, we find that these two types of indicators reduce to entanglement measure for bipartite pure states. Specifically, we also derive the relationship between these two indicators and the entanglement measure $I$-concurrence.