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arXiv · 2503.09169

Long-range bipartite entanglement in XXZ spin chains with the exponential and power-law long-range interactions

Na Li·Yang Zhao·Wen-Long Ma·Z. D. Wang·Yan-Kui Bai
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Abstract

Long-range bipartite entanglement (LBE) and its distribution properties are studied in XXZ spin chains with the 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 the 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\v{z}ek-Imoto bound for the prototypical long-range XXZ model, having potential applications in quantum information processing.

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Na Li, Yang Zhao, Wen-Long Ma, Z. D. Wang, Yan-Kui Bai. 2025-03-12. Long-range bipartite entanglement in XXZ spin chains with the exponential and power-law long-range interactions. https://doi.org/10.1103/99ck-qnqs

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