Bao Jia, Shen Longhui, Liu Hongying, Guo Bin, Sun Zhaoyu
Department of Physics, Wuhan University of Technology, Wuhan 430070, People's Republic of China.
School of Electrical and Electronic Engineering, Wuhan Polytechnic University, Wuhan 430023, People's Republic of China.
J Phys Condens Matter. 2024 Aug 5;36(44). doi: 10.1088/1361-648X/ad682a.
We investigate both bipartite and multipartite nonlocality in theJ1-J2Heisenberg model. Bipartite nonlocality is measured by the Clauser-Horne-Shimony-Holt inequality, while multipartite nonlocality is explored through Bell-type inequalities. Our findings reveal that neither ground-state nor full thermal-state nonlocality reliably characterizes quantum phase transitions (QPTs). However, we uncover that the mixed-state nonlocality of the ground and first excited states exhibits distinctive characteristics applicable to both bipartite and multipartite scenarios. We also demonstrate how mixed-state quantum correlation behaviors depend on varying temperature regimes. In the bipartite case, we observe a phenomenon known as 'correlation reversal' with increasing temperature, a previously unreported occurrence in other models. For the multipartite case, the ability to signify phase transitions is significantly enhanced as the temperature rises. Furthermore, we discover a linear scaling effect that provides valuable insights for extrapolating QPTs in the thermodynamic limit asN→∞. Additionally, we identify the critical temperature at which mixed-state nonlocality becomes a reliable indicator of phase transitions.
我们研究了J1-J2海森堡模型中的二分和多分非定域性。二分非定域性通过克劳泽-霍恩-希莫尼-霍尔特不等式来衡量，而多分非定域性则通过贝尔型不等式来探究。我们的研究结果表明，基态和完全热态的非定域性都不能可靠地表征量子相变（QPTs）。然而，我们发现基态和第一激发态的混合态非定域性呈现出适用于二分和多分情形的独特特征。我们还展示了混合态量子关联行为如何依赖于不同的温度范围。在二分情形中，我们观察到随着温度升高出现一种被称为“关联反转”的现象，这在其他模型中未曾报道过。对于多分情形，随着温度升高，表征相变的能力显著增强。此外，我们发现一种线性标度效应，这为在热力学极限N→∞时外推QPTs提供了有价值的见解。另外，我们确定了混合态非定域性成为相变可靠指标的临界温度。
