Two-way and three-way negativities of three-qubit entangled states
S. Shelly Sharma, Naresh Kumar Sharma · Physical Review A · 2007
We propose to quantify three-qubit entanglement using global negativity along with $K$-way negativities, where $K=2$ and 3. The principle underlying the definition of $K$-way negativity for pure and mixed states of $N$ subsystems is a positive partial transpose sufficient condition. However, $K$-way partial transpose with respect to a subsystem is defined so as to shift the focus to $K$-way coherences instead of $K$ subsystems of the composite system. A quantum state of a three-qubit system is characterized by the coherences measured by global, two-way, and three-way negativities. For a canonical state of three-qubit system, entanglement measures for genuine tripartite entanglement, W-like entanglement, and bipartite entanglement can be related to two-way and three-way negativities.