近日，法国巴黎城市大学的Adam Nahum及其研究团队取得一项新进展。经过不懈努力，他们对具有随机符号耦合的海森堡自旋链进行研究。相关研究成果已于2024年8月29日在国际知名学术期刊《美国科学院院刊》上发表。

该研究团队研究了一维量子海森堡链，该链具有随机铁磁或反铁磁耦合[一个之前已通过近似强无序重整化群（RG）方法研究的模型]。研究人员发现，至少对于足够大的自旋S，基态具有“自旋玻璃”序。在此状态之上的自旋波具有动力学指数Z=3/2，介于反铁磁体的z=1和铁磁体的z=2之间。

密度矩阵重整化群（DMRG）模拟结果与自旋S=1和S=3/2的分析结果吻合良好。S=1/2的情况显示出较大的有限尺寸效应，研究人员推测该情况也具有序，但有序矩较小。

附：英文原文

Title: Heisenberg spin chain with random-sign couplings

Author: Fava, Michele, Jacobsen, Jesper Lykke, Nahum, Adam

Issue&Volume: 2024-8-29

Abstract: We study the 1D quantum Heisenberg chain with randomly ferromagnetic or antiferromagnetic couplings [a model previously studied by approximate strong-disorder renormalization group (RG)]. We find that, at least for sufficiently large spin S, the ground state has “spin glass” order. The spin waves on top of this state have the dynamical exponent Z=3/2, intermediate between the values z = 1 of the antiferromagnet and z = 2 of the ferromagnet. Density matrix renormalization group (DMRG) simulations are in good agreement with the analytical results for spins S = 1 and S=3/2. The case S=1/2 shows large finite size effects: We suggest that this case is also ordered, but with a small ordered moment.

DOI: 10.1073/pnas.2401292121

Source: https://www.pnas.org/doi/abs/10.1073/pnas.2401292121

来源：科学网 小柯机器人