Decoherence-immune generation of highly entangled states for two atoms

This paper proposes a decoherence-immune scheme forgenerating highly entangled states for two atoms trapped in a cavity.The scheme is based on two resonant atom-cavity interactions.Conditional upon the detection of no photon, the two atoms mayexchange an excitation via the first resonant interaction, whichleads to entanglement. Due to the loss of the excitation, the twoatoms are in a mixed entangled state. With the help of an auxiliaryground state not coupled to the cavity mode, the state related tothe excitation loss is eliminated by the detection of a photonresulting from the second resonant interaction. Thus, the fidelityof entanglement is almost not affected by the decoherence.