光晶格中自旋3/2超冷费米原子的Mott绝缘态及其量子相变  

Mott insulating states and their quantum phase transitions of interacting spin-3/2 ultracold fermionic atoms on optical lattices

作　　者：张广铭[1] 涂鸿浩[1] 

机构地区：[1]清华大学物理系,北京100084

出　　处：《中国科学：物理学、力学、天文学》2011年第4期356-368,共13页Scientia Sinica Physica,Mechanica & Astronomica

摘　　要：我们首先简要介绍了超冷原子和光晶格,然后利用推广的单带Hubbard模型讨论了二维正方光晶格中自旋3/2费米型超冷原子体系中的几种Mott绝缘态,其中该系统的自旋自由度具有较大SO(5)对称性.对于对称性破缺的自旋四极矩有序态和自旋偶极-八极矩共存有序态,我们详细研究了系统的低能集体激发模式-Goldstone玻色激发的具体行为.在SU(4)对称点附近,我们发现强烈的量子涨落可能会演生出一个SU(4)π通量的自旋液体态.对此,我们还分析了这两种奇异量子态之间可能存在的量子相变.We first introduce the ultracold atoms and the optical lattices. Then, we analyze various Mott insulating phases of interacting spin-3/2 fermionic ultracold atoms in two-dimensional square optical lattices. Using a generalized Hubbard model, we identify two distinct symmetry breaking phases： the spin-quadrupole ordering phase and the spin-dipole-spin-octupole ordering phase. Near the SU（4） symmetric point, we find that an algebraic spin liquid phase may emerge due to strong quantum fluctuations. Finally, the possible quantum phase transitions between these exotic phases are also discussed.

关 键 词：超冷原子 Mott绝缘态 集体激发 量子相变 

分 类 号：O431.2[机械工程—光学工程]