Institut de théorie des phénomènes physiques, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
Phys Rev Lett. 2010 Dec 31;105(26):265301. doi: 10.1103/PhysRevLett.105.265301. Epub 2010 Dec 21.
Combining a semiclassical analysis with exact diagonalizations, we show that the ground state of the SU(3) Heisenberg model on the square lattice develops three-sublattice long-range order. This surprising pattern for a bipartite lattice with only nearest-neighbor interactions is shown to be the consequence of a subtle quantum order-by-disorder mechanism. By contrast, thermal fluctuations favor two-sublattice configurations via entropic selection. These results are shown to extend to the cubic lattice, and experimental implications for the Mott-insulating states of three-flavor fermionic atoms in optical lattices are discussed.
我们通过半经典分析和精确对角化相结合的方法，证明了在正方形晶格上的 SU(3)海森堡模型的基态会发展出三亚晶格长程有序。这种在只有最近邻相互作用的二部晶格中出现的惊人模式，被证明是一种微妙的量子无序有序机制的结果。相比之下，热涨落通过熵选择有利于二亚晶格构型。这些结果被扩展到立方晶格，并且讨论了它们对光学晶格中三费米子原子的莫特绝缘态的实验意义。
