Abstract We present a high efficient entanglement concentration protocol (ECP) for four-electron system in a less-entangled cluster state. In this ECP, we only require one pair of less-entangled electron cluster state and one ancillary electron to complete the task. With the help of the controlled-not (CNOT) gate, the concentrated maximally entangled state can be remained for further application with some success probability. On the other hand, the discarded items can be reused to obtain a high success probability. All the features make this ECP useful in current quantum information field.
