Generation of W_n state with three atoms trapped in two remote cavities coupled by an optical fibre

We propose two schemes for the generation of the W_n state with three atoms separately trapped in two distant cavities coupled by an optical fibre. One is implemented by controlling the interaction time, the other is implemented via the adiabatic passage. The influence of various decoherence processes, such as spontaneous emission of the atoms and photon leakages of the cavities and the optical fibre, on the fidelity is also investigated. It is found that the W_n state can be generated with high fidelity even when these decoherence processes are present.