自旋轨道耦合Su-Schrieffer-Heeger模型的量子相变  

Quantum Phase Transition of Su-Schrieffer-Heeger Model with Spin-orbit Coupling

作　　者：孙文奇 梁军军[1] SUN Wenqi;LIANG Junjun(Institute of Theoretical Physics,Shanxi University,Taiyuan 030006,China)

机构地区：[1]山西大学理论物理研究所,山西太原030006

出　　处：《山西大学学报（自然科学版）》2024年第3期583-590,共8页Journal of Shanxi University(Natural Science Edition)

基　　金：国家自然科学基金(2016012)。

摘　　要：本文研究了粒子间短程排斥相互作用和自旋轨道耦合效应对SSH (Su-Schrieffer-Heeger)模型量子相与相变的影响。利用密度矩阵重整化群方法(Density-matrix Renormalization Group Method, DMRG)分析了粒子数密度分布、密度结构因子、纠缠熵和纠缠谱等,在弱相互作用区间,不同自旋轨道耦合参数下存在数目不一样的非平庸拓扑边缘态,而随着相互作用的增强,系统手征对称自发破缺,在自旋轨道耦合强度和相互作用的高值区域,出现密度波相。最后确定了相边界进而得到相图。用密度结构因子刻画该模型的拓扑相变点时,发现在小尺寸下,密度结构因子峰值在相变点存在突变,而当系统尺寸足够大时,突变消失,峰值呈现出奇异性。In this paper,the effects of short-range repulsion interactions between particles and spin-orbit coupling(SOC)effects on quantum phase and phase transitions of SSH(Su-Schrieffer-Heeger)models are studied.We used the DMRG(density-matrix renor-malization group method)to analyze the particle number density distribution,density structure factor,entanglement entropy and en-tanglement spectrum,etc.,in the weak interaction interval,there are a different number of non-trivial topological edge states under different spin-orbit coupling parameters,and with the enhancement of the interaction,the system chiral symmetry spontaneously breaks,and the density wave phase appears in the high-value region of spin-orbit coupling strength and interaction.We finally deter-mined the phase boundary and obtained the phase diagram.When the density structure factor is used to characterize the topological phase transition point of the model,it is found that the peak of the density structure factor has mutations at the phase transition point at the small size,and when the system size is large enough,the mutation disappears and the peak value shows singularity.

关 键 词：超冷费米气体 自旋轨道耦合 密度波相 拓扑 

分 类 号：O469[理学—凝聚态物理]