论文标题
旋转S = 1/2抗磁磁性海森贝格模型中的多运动激发
Multispinon excitations in the spin S=1/2 antiferromagnetic Heisenberg model
论文作者
论文摘要
借助旋转操作员的换向关系，我们首先写出具有分层结构的旋转易感性和相关相关函数的运动方程，然后在“软截止”近似值下，为旋转运动的旋转运动方程式提供了旋转s = 1/2抗铁磁抗磁性抗铁磁性的动力的范围/不限制系统是否独立于系统是否独立于系统。分别申请链，方格和蜂窝状晶格，我们通过求解这组方程来获得低洼激动的上部和最低边界。对于链条，低洼激发的上部和最低边界与Bethe Ansatz获得的确切链接相同，而基本激发是Spinon对。对于平方晶格，旋转波激发（镁元素）位于接近低洼激动的最低边界的区域中，而多型激发发生在靠近低层兴奋的上边界的高能量区域。对于蜂窝状晶格，我们有一种低洼兴奋的“模式”。目前的结果遵守了Lieb-Schultz-Mattis定理，它们也与最新的中子散射观测和方形晶格的数值模拟一致。
With the commutation relations of the spin operators, we first write out the equations of motion of the spin susceptibility and related correlation functions that have a hierarchical structure, then under the "soft cut-off" approximation, we give a set of equations of motion of spin susceptibilities for a spin S=1/2 antiferromagnetic Heisenberg model, that is independent of whether or not the system has a long range order in the low energy/temperature limit. Applying for a chain, a square lattice and a honeycomb lattice, respectively, we obtain the upper and the lowest boundaries of the low-lying excitations by solving this set of equations. For a chain, the upper and the lowest boundaries of the low-lying excitations are the same as that of the exact ones obtained by the Bethe ansatz, where the elementary excitations are the spinon pairs. For a square lattice, the spin wave excitation (magnons) resides in the region close to the lowest boundary of the low-lying excitations, and the multispinon excitations take place in the high energy region close to the upper boundary of the low-lying excitations. For a honeycomb lattice, we have one kind of "mode" of the low-lying excitation. The present results obey the Lieb-Schultz-Mattis theorem, and they are also consistent with recent neutron scattering observations and numerical simulations for a square lattice.
