Long-range bipartite entanglement in XXZ spin chains with exponential and power-law long-range interactions
Na Li, Yang Zhao, Wen-Long Ma +2 more
Long-range bipartite entanglement (LBE) and its distribution properties are studied in XXZ spin chains with exponential and power-law long-range interactions (ELRIs and PLRIs). LBE quantified by two-qubit concurrence decays exponentially along with two-site distance in the infinite chain with ELRIs in the thermodynamic limit, and the long-range behavior of two-spin entanglement can detect the quantum phase transition and identify different quantum phases away from the critical point. Moreover, a fine-grained LBE distribution relation is obtained for the infinite XXZ spin chain. On the other hand, in the finite XXZ spin chain with conventional PLRIs, the long-range concurrence decays algebraically and the total one is no longer monotonic along with the chain length. The total LBE distribution property can exhibit a piecewise function, which has a close relationship with the decaying mode and strength of PLRIs. These LBE relations can be regarded as the generalization of Koashi-Bu\ifmmode \check{z}\else \v{z}\fi{}ek-Imoto bound for the prototypical long-range XXZ model, having potential applications in quantum information processing.
arXiv:2503.09169•Physical review. B./Physical review. B•Sep 22, 2025•0 citations