Hermele Michael, Gurarie Victor, Rey Ana Maria
Department of Physics, University of Colorado, Boulder, Colorado 80309, USA.
Phys Rev Lett. 2009 Sep 25;103(13):135301. doi: 10.1103/PhysRevLett.103.135301.
We study Mott insulators of fermionic alkaline earth atoms, described by Heisenberg spin models with enhanced SU(N) symmetry. In dramatic contrast to SU(2) magnetism, more than two spins are required to form a singlet. On the square lattice, the classical ground state is highly degenerate and magnetic order is thus unlikely. In a large-N limit, we find a chiral spin liquid ground state with topological order and Abelian fractional statistics. We discuss its experimental detection. Chiral spin liquids with non-Abelian anyons may also be realizable with alkaline earth atoms.
我们研究了费米子碱土金属原子的莫特绝缘体，其由具有增强的SU(N)对称性的海森堡自旋模型描述。与SU(2)磁性形成鲜明对比的是，形成单重态需要两个以上的自旋。在正方形晶格上，经典基态高度简并，因此不太可能出现磁有序。在大N极限下，我们发现了具有拓扑序和阿贝尔分数统计的手征自旋液体基态。我们讨论了其实验检测方法。具有非阿贝尔任意子的手征自旋液体也可能用碱土金属原子实现。
