Universal Quantum Entanglement Concentration Gate
  We construct a Universal Quantum Entanglement Concentration Gate (QEC-Gate). Special times operations of QEC-Gate can transform a pure 2-level bipartite entangled state to nearly maximum entanglement. The transformation can attain any required fidelity with optimal probability by adjusting concentration step. We also generate QEC-Gate to the Schmidt decomposable multi-partite system. 
Zi-Yang Wang, Chuan-Wei Zhang, Chuan-Feng Li, and Guang-Can Guo   (University of Science and Technology of China)