Preparation of entangled W states based on cavity QED system

We present a qubit-loss-free (QLF) fusion scheme for generating large-scale atom W states in cavity quantum electrodynamics (QED) system. Compared to the most current fusion schemes which are conditioned on the case where one particle can be extracted from each initial W state to the fusion process, our scheme will access one or two particles from each W state. Based on the atom–cavity-field detuned interaction, three | W 〉 n + m + t states can be generated from the | W 〉 n , | W 〉 m , and | W 〉 t states with the help of two auxiliary atoms, and three | W 〉 n + m + t + q states can be generated from | W 〉 n , | W 〉 m , | W 〉 t , and a | W 〉 q state with the help of three auxiliary atoms. Comparing the numerical simulations of the resource cost of fusing three small-size W states based on the previous schemes, our fusion scheme seems to be more efficient. This QLF fusion scheme can be generalized to the case of fusing k different or identical particle W states. Furthermore, with no qubit loss, it greatly reduces the number of fusion steps and prepares W states with larger particle numbers.