光学晶格中一维排斥费米气体的超流特性  

Superfluidity in a Trapped Gas of Repulsive Fermi Gases Loaded on an Optical Lattice

作　　者：李小磊[1] 梁军军[1] 

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）》2013年第2期204-207,共4页Journal of Shanxi University(Natural Science Edition)

基　　金：国家自然科学基金(11005071)

摘　　要：利用密度重整化群研究了在粒子数小于半填充时一维光学晶格中费米子气体的超流特性.研究发现当格点总数N<22,排斥相互作用强度大于临界值时,粒子的束缚态会对应着费米系统在势阱中心产生的Mott绝缘态,边缘则为超流态.而当格点总数增大时,上述结论会有所不同.增强排斥相互作用首先出现的负的两粒子束缚能只能说明系统此时处于超流态,但是并没有相应的Mott绝缘态,只有当排斥作用足够强时才会有Mott绝缘态的出现,上述讨论进一步改善了文献[5]的结论.The superfluidity in one-dimensional Fermi gases below the half-filling,loaded on optical lattices is investigated by density-matrix renormalization-group （DMRG）. When the lattice size is small than twen- ty-two and the strength of the repulsive interaction exceeds a critical value, the binding energy becomes negative while the Mott insulating core appears in the center o{ the trap and superfluid is on both sides. The above conclusions will be different with larger lattice size. When the repulsive interaction is increased for larger lattice size,first the negative binding energy indicates that the superfluid phase appears but with- out Mott insulating core. When the repulsive interaction is sufficiently strong, the Mott insulating core will appear. The above discussion generalizes the conclusion of the literature[5].

关 键 词：Fermi—Hubbard模型 密度重整化群 束缚能 Mott绝缘态 

分 类 号：O469[理学—凝聚态物理]