Transformations of W-type entangled states

The transformations of W-type entangled states by using local operations assisted with classical communication are investigated. For this purpose, a parametrization of the W-type states which remains invariant under local unitary transformations is proposed and a complete characterization of the local operations carried out by a single party is given. These are used for deriving the necessary and sufficient conditions for deterministic transformations. A convenient upper bound for the maximum probability of distillation of arbitrary target states is also found. (C) 2010 American Institute of Physics. [doi:10.1063/1.3481573]