Characterizing nonclassical correlations via local quantum Fisher information

TL;DR

This paper introduces two methods to quantify quantum correlations using quantum Fisher information, linking them to quantum metrology and geometric discord, and demonstrating their effectiveness in pure states.

Contribution

It proposes novel QFI-based measures of quantum correlations and relates them to existing concepts like geometric discord, enhancing understanding of quantum resources.

Findings

Quantum correlation can be identified by differences in Fisher information hierarchies.

QFI-based quantum correlations match geometric discord for pure states.

The hierarchy of measurement-induced Fisher information reveals quantum correlations.

Abstract

We define two ways of quantifying the quantum correlations based on quantum Fisher information (QFI) in order to study the quantum correlations as a resource in quantum metrology. By investigating the hierarchy of measurement-induced Fisher information introduced in Lu et al. [X. M. Lu, S. Luo, and C. H. Oh, Phys Rev. A 86, 022342 (2012)], we show that the presence of quantum correlation can be confirmed by the difference of the Fisher information induced by the measurements of two hierarchies. In particular, the quantitative quantum correlations based on QFI coincide with the geometric discord for pure quantum states.