Entanglement concentration of three-partite states
Berry Groisman, Noah Linden, Sandu Popescu · Physical Review A · 2005
We investigate the concentration of multiparty entanglement by focusing on a simple family of three-partite pure states, superpositions of Greenberger-Horne-Zeilinger states and singlets. Despite the simplicity of the states, we show that they cannot be reversibly concentrated by the standard entanglement concentration procedure, to which they seem ideally suited. Our results cast doubt on the idea that for each $N$ there might be a finite set of $N$-party states into which any pure state can be reversibly transformed. We further relate our results to the concept of locking of entanglement of formation.