Quantifying nonclassical correlations relative to local channels
Cong Xu, Tao Li, Ruonan Ren, Ming-Jing Zhao, Shao-Ming Fei
TL;DR
This work introduces the modified Wigner-Yanase-Dyson (MWYD) skew information $T_(\rho,\Phi)$ for a state relative to a quantum channel and defines a corresponding quantum-correlation measure $D^T_(\rho_{AB}|\Phi_A)$. The authors prove key properties including nonnegativity, unitary covariance, convexity, and contractivity, and relate these to an existing measure $D_$ via a concrete example. They analyze correlations relative to three channel classes: von Neumann measurements, unitary channels, and twirling channels, obtaining optimized and closed-form expressions and connecting to coherence measures and geometric discord. The results provide a channel-relative resource quantify for nonclassical correlations with explicit forms for standard channels and a pathway for interpreting non-Hermitian operator contributions through $T_(\rho,\Phi)$.
Abstract
Nonclassical correlations are significant physical resources with extensive applications in quantum information processing. We introduce the modified Wigner-Yanase-Dyson skew information of a quantum state relative to a quantum channel, and a quantitative measure of quantum correlations. Their basic properties are explored in detail. Through a specific example, we also compare our correlations measure with the existing one. Moreover, the correlations relative to various channels including the von Neumann measurements, the unitary channels and the twirling channels are analyzed.
