Multipartite electronic entanglement purification with charge detection
  We present a multipartite entanglement purification scheme in a Greenberger-Horne-Zeilinger state for electrons based on their spins and their charges. This scheme works for purification with two steps, i.e., bit-flipping error correction and phase-error flip error correction. By repeating these two steps, the parties in quantum communication can get some high-fidelity multipartite entangled electronic systems. 
Yu-Bo Sheng, Fu-Guo Deng, and Gui-Lu Long
quant-ph