Deterministic Generation of W States for Any Number of Distant Atoms via Adiabatic Passage

We propose a deterministic scheme for preparing any number of distant atoms in a W state. The atoms are respectively trapped in spatially separated optical cavities connected by the fibers. Our scheme utilizes the adiabatic passage along dark state, and is robust against the atomic spontaneous emission and the decays of cavities. The numerical simulation of entanglement fidelity shows that the losses of fibers can be negligible under certain conditions. All of the advantages make the protocol more practical than previous ones.