Experimental entanglement quantification and verification via uncertainty relations Zhi-Wei Wang, Yun-Feng Huang, Xi-Feng Ren, Yong-Sheng Zhang and Guang-Can Guo EPL, 78 4 (2007) 40002 Published online: 03 May 2007 DOI: 10.1209/0295-5075/78/40002