Abstract: Due to the no-cloning theorem, the approximate cloning of quantum state with higher fidelity has attracted a lot of attention. Most of the previous studies focused on the cloning of single-particle states, which cannot clone quantum entangled states for multipartite system. Few schemes were proposed for cloning multiparticle states, which consume more entanglement resources with loss of qubits, the fidelity of the cloned state is relatively low. In this paper, we propose cloning schemes for bipartite and tripartite entangled states based on photonic quantum walk and entanglement swapping. The results show that two high-fidelity (up to 0.75) cloned states can be obtained with less quantum resource consumption. Because of the simple cloning steps, few quantum resources and high fidelity, our schemes are efficient and feasible. In addition, no quantum system will be traced out from our cloning machines, which reduces the waste of quantum resources.

Key words: quantum optics, entanglement cloning, photonic quantum walk, multipartite entanglement