Distillability and partial transposition in bipartite systems
Wolfgang Dür, J. I. Cirac, Maciej Lewenstein, Dagmar Bruß · Physical Review A · 2000
We study the distillability of a certain class of bipartite density operators which can be obtained via depolarization starting from an arbitrary one. Our results suggest that nonpositivity of the partial transpose of a density operator is not a sufficient condition for distillability, when the dimension of both subsystems is higher than 2.