Separability and Distillability of Multiparticle Quantum Systems
Wolfgang Dür, J. I. Cirac, R. Tarrach · Physical Review Letters · 1999
We present a family of 3-qubit states to which any arbitrary state can be depolarized. We fully classify those states with respect to their separability and distillability properties. This provides a sufficient condition for nonseparability and distillability for arbitrary states. We generalize our results to $N$-particle states.