Linear optical scheme to demonstrate genuine multipartite entanglement for single-particle W states
Hyunchul Nha · Physical Review A · 2008
We consider the method of entanglement witness operator to verify genuine multipartite entanglement for single-particle $W$ states involving $N$ parties. In particular, linear optical schemes using photodetectors and beam splitters are proposed to implement two different types of witness operator in experiment. The first scheme that requires only a single measurement setting is shown to detect genuine multipartite entanglement for the overall efficiency beyond $1\ensuremath{-}1/N$. On the other hand, the second scheme with $N+1$ measurement settings achieves success at a significantly lowered efficiency than $1\ensuremath{-}1/N$.