@article {1439, title = {Non-Additivity of the Entanglement of Purification (Beyond Reasonable Doubt) }, year = {2012}, month = {2012/06/06}, abstract = { We demonstrate the convexity of the difference between the regularized entanglement of purification and the entropy, as a function of the state. This is proved by means of a new asymptotic protocol to prepare a state from pre-shared entanglement and by local operations only. We go on to employ this convexity property in an investigation of the additivity of the (single-copy) entanglement of purification: using numerical results for two-qubit Werner states we find strong evidence that the entanglement of purification is different from its regularization, hence that entanglement of purification is not additive. }, url = {http://arxiv.org/abs/1206.1307v1}, author = {Jianxin Chen and Andreas Winter} }