Department of Physics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan.
Phys Rev Lett. 2018 Nov 30;121(22):225303. doi: 10.1103/PhysRevLett.121.225303.
Large-spin cold atomic systems can exhibit unique phenomena that do not appear in spin-1/2 systems. We report the observation of nearest-neighbor antiferromagnetic spin correlations of a Fermi gas with SU(N) symmetry trapped in an optical lattice. The precise control of the spin degrees of freedom provided by an optical pumping technique enables us a straightforward comparison between the cases of SU(2) and SU(4). Our important finding is that the antiferromagnetic correlation is enhanced for the SU(4)-spin system compared with SU(2) as a consequence of a Pomeranchuk cooling effect. This work is an important step towards the realization of novel SU(N>2) quantum magnetism.
大自旋冷原子体系可以表现出在自旋-1/2 体系中不存在的独特现象。我们报告了在光学晶格中囚禁的具有 SU(N)对称性的费米气体的最近邻反铁磁自旋关联的观测结果。光学泵浦技术提供的自旋自由度的精确控制使我们能够在 SU(2)和 SU(4)两种情况下进行直接比较。我们的重要发现是，由于庞加莱冷却效应，与 SU(2)相比，SU(4)自旋体系的反铁磁关联得到了增强。这项工作是实现新型 SU(N>2)量子磁体的重要一步。
