Entanglement distillation for atomic states via cavity QED

Following a recent proposal (Phys. Rev. Lett. 85 (2000) 2392) about quantum information processing using dispersive atom–cavity interaction, in this paper, we proposed a physical scheme to concentrate the pure non-maximally entangled atomic states via cavity QED by using atomic collision in a far-off-resonant cavity. The most distinctive advantage of our scheme is that there is no excitation of cavity mode during the distillation procedure. Therefore the requirement on the quality of cavity is greatly loosened.