Preparation of W state among spatially separated atomic ensembles collectively controlled by a single atom via adiabatic passage

We propose a way to prepare W state among atomic ensembles via stimulated Raman adiabatic passage (STIRAP) technique. The atomic ensembles are trapped in spatially separated cavities collectively linked to another cavity trapping a single atom by optical fibers. Our strictly numerical simulations show that, the atomic spontaneous emission, the cavity decay and the fiber loss are efficiently suppressed by the engineering adiabatic passage. The method can be generalized to prepare W state among any number of atomic ensembles. We believe that our proposal will promote development of quantum teleportation, especially quantum state engineering of multi-target-qubit collectively controlled by a qubit.