Nonlocality and efficiency of three-qubit partially entangled states

We analyse nonlocal properties in three-qubit partially entangled Wn states to understand the efficiency of these states as entangled resources. Our results show that Wn states always violate the three-qubit Svetlichny inequality, and the degree of violation increases with the increase in degree of entanglement. We find that nonlocal correlations in W1 states are the highest in comparison to all other Wn states. We further demonstrate that within the limits of experimentally achievable measurements the W1 state proves to be a better quantum resource for specific protocols in comparison to standard W states, even though the degree of entanglement and nonlocality in the W1 state are less than the degree of entanglement and nonlocality in the standard W state. Moreover, we also consider superpositions of the Greenberger–Horne–Zeilinger (GHZ) state with W and W1 states to show that more entanglement is not a necessity for better efficiency in all protocols. In addition, we also demonstrate the preparation of three qubit quantum states represented as linear superpositions of the GHZ state with W and W1 states.