title: Catalysis of entanglement manipulation for mixed states
abstract: We consider entanglement-assisted remote quantum state manipulation of bipartite mixed states. Several aspects are addressed: we present a class of mixed states of rank two that can be transformed into another class of mixed states under entanglement-assisted local operations with classical communication, but for which such a transformation is impossible without assistance. Furthermore, we demonstrate enhancement of the efficiency of purification protocols with the help of entanglement-assisted operations. Finally, transformations from one mixed state to mixed target states which are sufficiently close to the source state are contrasted with similar transformations in the pure-state case.
authors.affiliation: Institut fur Physik, Universitat Potsdam, 14469 Potsdam, Germany.
authors.initials: J
authors.lastname: Eisert
authors.initials: M
authors.lastname: Wilkens