Optimal four-copy detection of the three-tangle and its fault-tolerant cost

Federico Tomás B. Pérez, Berta Casas, I-Chi Chen +3

The three-tangle, ${\tau }_3$, is a measure of genuine tripartite entanglement that distinguishes GHZ-type from W-type entanglement in pure three-qubit states. Here, we identify the stat…