@article {1453, title = {Existence of Universal Entangler}, journal = {Journal of Mathematical Physics}, volume = {49}, year = {2008}, month = {2008/01/01}, pages = {012103}, abstract = { A gate is called entangler if it transforms some (pure) product states to entangled states. A universal entangler is a gate which transforms all product states to entangled states. In practice, a universal entangler is a very powerful device for generating entanglements, and thus provides important physical resources for accomplishing many tasks in quantum computing and quantum information. This Letter demonstrates that a universal entangler always exists except for a degenerated case. Nevertheless, the problem how to find a universal entangler remains open. }, doi = {10.1063/1.2829895}, url = {http://arxiv.org/abs/0704.1473v2}, author = {Jianxin Chen and Runyao Duan and Zhengfeng Ji and Mingsheng Ying and Jun Yu} }