Abstract: Based on the cavity quantum electrodynamtics (QED) syst em, two atoms were simultaneously sent through one vacuum cavity field to realiz e the fusion of two W states based on resonant interaction between the two atoms a nd the cavity field. One of the two atoms was from the Natom W state, and the other one was from the Matom W state. The cavity field was detected after the atoms and the cavity fie ld was resonant. The results show that if only one photon in the cavity is detec ted, an (N+M)atom W state can be genera ted with some probability. If no photon is detected in the cavity, the two atoms are detected. If only one excitation is detected between the two atoms, an (N+M-2)atom W state can be generated with some probability. If no excitati on is detected between the two atoms, the left (N-1)atom W state and ( M-1)atom W state can be refused by the same scheme.

Key words: W state, resonant interaction, cavity quantum electrodynamtics (QED) system, quantum state fusion