Long-distance entanglement in antiferromagnetic XXZ spin chain with alternating interactions

In this paper, the quantum entanglement (concurrence) of one-dimensional antiferromagnetic XXZ spin system with alternating nearest-neighbor interactions is studied by means of the density matrix renormalization group method with matrix product state form. The ground-state energy, long-distance entanglement and entanglement distribution are calculated, and the effects of alternating interactions, anisotropy and open boundary condition on them are discussed. It is found that the alternating interactions favor the generation and development of long-distance entanglement, while anisotropy inhibits that. For the entanglement distribution of the system, it is also found that the alternating interactions and open boundary condition induce the dimerization on odd and even bonds, respectively, while anisotropy always suppresses this behavior. Furthermore, both nearest-neighbor and long-distance entanglements are converged to certain values with increasing system size.