Local, nonlocal quantumness and information theoretic measures

Abstract

It has been suggested that there may exist quantum correlations that go beyond entanglement. The existence of such correlations can be revealed by quantum discord, but not by the conventional measure of entanglement. We argue that a state displays quantumness that can be of local and nonlocal origin. The physical quantity such as the quantum discord probes not only the nonlocal quantumness but also the local quantumness, such as the "local superposition". This can be a reason why such measures are non-zero when there is no entanglement. We consider a generalized version of the Werner state to demonstrate the interplay of local quantumness, nonlocal quantumness, and classical mixedness of a state.

7 pages, 8 figures. Title changed. Accepted for publication in IJQI

References in corpus (6)

• Optimization of entanglement witnesses
• Behavior of Quantum Correlations under Local Noise
• Necessary and sufficient conditions for bipartite entanglement
• Separability and correlations in composite states based on entropy methods
• A pedagogical overview of quantum discord
• Teleportation via a mixture of a two qubit subsystem of a N-qubit W and GHZ state

Cited by in corpus (2)

• Quantum mutual information and quantumness vectors for multi-qubit systems
• Mutual Uncertainty, Conditional Uncertainty and Strong Sub-Additivity