Qubit-loss-free fusion of W states in cavity quantum electrodynamics system

In this paper, a new qubit-loss-free fusion scheme for atom W states has been proposed in cavity quantum electrodynamics system. Based on the resonant interactions between the atoms and the cavity modes, a larger-scale atom W state can be generated from three or four small-scale entangled states on the condition that one or two qubit of each W state is permitted to enter the fusion mechanism. The premise of all current fusion schemes is that only one particle can be extracted from each W state to be fused, and with the progress of experimental technology, two particles can be extracted. In this case, the qubit-loss-free fusion scheme will be realized for fusing more W states without any ancillary particles. In addition, the fusion of the atomic states can be achieved through the detection on cavity mode rather than the complex atomic detection, which makes the preparation scheme be more efficient andsimpler.