Shortcuts to adiabatic passage for fast preparation of multipartite entanglement among atomic ensembles

In this paper, we describe a scheme for preparation of W state among atomic ensembles by constructing shortcuts to adiabatic passage (STAP) based on the “Lewis-Riesenfeld (LR) invariants” in spatially separated cavities connected by optical fibers. The scheme is not only fast, but robust against variation of the parameters. The influence of various decoherence processes on the fidelity is discussed as well. Numerical simulations demonstrate that the fidelity of the three-atomic-ensemble W state is relatively high. Moreover, the method can be generalized to prepare W state among any number of atomic ensembles