简谐势中非对角AAH晶格上费米气体的基态性质  

Ground-state Properties of a Fermi Gas in Off-diagonal AAH Lattice with a Harmonic Trap

作　　者：张奋华 王利[1] 张云波[1] ZHANG Fenhua;WANG Li;ZHANG Yunbo(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）》2020年第2期287-292,共6页Journal of Shanxi University(Natural Science Edition)

基　　金：国家自然科学基金(11404199,11674201);山西省自然科学基金(2015021012)。

摘　　要：文章主要研究了处于简谐势中一维非对角Aubry-André-Harper(AAH)晶格上费米气体的基态性质。着重分析了系统的基态性质随着非对角无序强度增加而发生的变化。基于严格的数值方法,计算了不同无序强度下体系多粒子基态的逆参与率、实空间粒子密度分布、单粒子密度矩阵及动量分布等物理量。计算结果表明,当无序强度λod>t时,费米气体的基态的逆参与率会突然增强,而且系统的单体关联会由随距离增加呈幂律衰减转变为更快的指数衰减,这标志着费米气体进入了一个新的基态量子相。The ground state properties of a Fermi gas loaded in one-dimensional off-diagonal Aubry-André-Harper(AAH)lattice within a harmonic trap were investigated.Our attentions were mainly paid to the changes in the ground state properties of the system when the strength of the off-diagonal disorder increased.Based on a rigid numerical method,we calculated the inverse participation ratio,particle density profiles in real space,one-particle density matrices and momentum distributions of the many-body ground state for off-diagonal disorder of different strengths.The numerical results showed that the ground state inverse participation ratio of the Fermi gas would increase abruptly when the off-diagonal disorder strengthλod>t.Furthermore,the physical behavior of the single-particle correlation function for the ground state would change from being power-law decaying with distance to exponential decaying.This indicated that Fermi gas entered a new ground state quantum phase.

关 键 词：费米气体 非对角无序 AAH晶格 单粒子密度矩阵 动量分布 

分 类 号：O51[理学—低温物理]