标题： 二维SU(N)海森堡模型中反铁磁到价键固体的相变 显示英文标题

标题： Antiferromagnetic to valence-bond-soild transitions in two-dimensional SU(N) Heisenberg models with multi-spin interactions

摘要： 我们研究了具有额外多自旋相互作用的二维海森堡反铁磁体，这些相互作用可以将系统驱动到单线态固体状态。 对于标准的SU(2)自旋，我们考虑了四自旋和六自旋相互作用。 我们发现具有相同临界指数的连续量子相变。 将对称性扩展到SU(N)，我们也发现对于N=3和4存在连续转变。 此外，我们还定量研究了序参量对称性从单线态固体相内部的Z4对称性到接近相变时的U(1)对称性的交叉过渡。 显示英文摘要

摘要： We study two-dimensional Heisenberg antiferromagnets with additional multi-spin interactions which can drive the system into a valence-bond solid state. For standard SU(2) spins, we consider both four- and six-spin interactions. We find continuous quantum phase transitions with the same critical exponents. Extending the symmetry to SU(N), we also find continuous transitions for N=3 and 4. In addition, we also study quantitatively the cross-over of the order-parameter symmetry from Z4 deep inside the valence-bond-solid phase to U(1) as the phase transition is approached.