Efficient electronic entanglement concentration assisted with single   mobile electron
  We present an efficient entanglement concentration protocol (ECP) for mobile electrons with charge detection. This protocol is quite different from other ECPs for one can obtain a maximally entangled pair from a pair of less-entangled state and a single mobile electron with a certain probability. With the help of charge detection, it can be repeated to reach a higher success probability. It also does not need to know the coefficient of the original less-entangled states. All these advantages may make this protocol useful in current distributed quantum information processing. 
Yu-Bo Sheng, Lan Zhou, Wei-Wen Cheng, Long-Yan Gong, and Sheng-Mei   Zhao
quant-ph