Ultracold gases of ytterbium: ferromagnetism and Mott states in an SU(6) Fermi system
Ultracold gases of ytterbium: ferromagnetism and Mott states in an SU(6) Fermi system
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DOI：
10.1088/1367-2630/11/10/103033
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发表时间：
2009-10-21
影响因子：
3.3
通讯作者：
Ueda, M.
中科院分区：
文献类型：
--
作者：
Cazalilla, M. A.;Ho, A. F.;Ueda, M.
有人认为，核自旋 I = 5/2 的镱 Yb-173 原子的超冷量子简并气体表现出扩大的 SU(6) 对称性。在朗道费米液体理论中，考虑了自旋通道中针对费米液体（Pomeranchuk）不稳定性的稳定性标准。着眼于铁磁性的 SU(n > 2) 推广，平均场理论表明，从顺磁体到巡回铁磁体的转变通常是一阶的。基于对称性，还讨论了一般 SU(n) 巡回铁磁基态及其拓扑激发。这些 SU(n > 2) 铁磁体可以通过使用光学方法或在光学晶格中增加散射长度来变得稳定。然而，在当前实验温度下的光学晶格中，根据 SU(6) Hubbard 模型的计算得出，不同填充的莫特态预计会共存于同一陷阱中。
It is argued that an ultracold quantum degenerate gas of ytterbium Yb-173 atoms having nuclear spin I = 5/2 exhibits an enlarged SU(6) symmetry. Within the Landau Fermi liquid theory, stability criteria against Fermi liquid (Pomeranchuk) instabilities in the spin channel are considered. Focusing on the SU(n > 2) generalizations of ferromagnetism, it is shown within mean-field theory that the transition from the paramagnet to the itinerant ferromagnet is generically first order. On symmetry grounds, general SU(n) itinerant ferromagnetic ground states and their topological excitations are also discussed. These SU(n > 2) ferromagnets can become stable by increasing the scattering length using optical methods or in an optical lattice. However, in an optical lattice at current experimental temperatures, Mott states with different filling are expected to coexist in the same trap, as obtained from a calculation based on the SU(6) Hubbard model.