利用Lanczos算法研究一维光晶格Fermi气体  

Study on Fermi Gas in One-dimensional Optical Lattice by Lanczos Method

作　　者：胡波 陈亮 韩榕生[1] 

机构地区：[1]华北电力大学数理学院,北京昌平102206

出　　处：《湖北理工学院学报》2017年第6期41-46,51,共7页Journal of Hubei Polytechnic University

基　　金：国家自然科学基金项目(项目编号:11504106)

摘　　要：研究了零温下一维光晶格Fermi气体随外加磁场和自旋轨道耦合(SOC)相互作用的变化特征。基于Fermi-Hubbard模型,采用Lanczos部分迭代法研究计算具有自旋轨道耦合(SOC)的一维费米链体系的基态波函数与基态能量,进一步得到超导配对序参量和磁化率的结果。计算结果表明,Lanczos迭代法在求解一维光晶格体系是收敛和有效的,外加磁场和SOC作用对BCS单重态的超导配对均具有抑制作用。另外在合适的磁场和SOC共同作用下存在Fulde-Ferrell-Larkin-Ovchinnikov(FFLO)相与BCS-FFLO混合相。通过与其他研究者的结果比较,体系特殊的相分布情况和非连续性相转变特征与较小的格点数可能相关。该结论对实验上探测BCS-FFLO混合相也具有指导意义。This paper studied one-dimensional Fermi chain with spin-orbit coupling（ SOC）. The variation trend of the systemic properties with magnetic field and SOC interaction at zero temperrature was investigated.Based on Fermi-Hubbard model,partial Lanczos iterative method was used to calculate ground wave function and ground state energy of the system,then paring order and magnetic susptibility were obtained. The results showed that the partial Lanczos iteration method was convergent and effective. The analysis indicated that the BCS superconducting singlet paring was suppressed by both magnetic field or SOC. When magnetic field and SOC coexist,Fulde-Ferrell-Larkin-Ovchinnikov（ FFLO） and FFLO-BCS phase can be obtained with certain parameters. By comparing with other researcher＇s results,the special phase distribution and non-continuous transformation characteristics perhaps associated with the small size of system. These conclusions were also instructive for the detection of FFLO-BCS phase in experiments.

关 键 词：Fermi-Hubbard模型 Lanczos迭代 自旋轨道耦合 FFLO相 BCS-FFLO混合相 

分 类 号：O413.3[理学—理论物理]