论文标题
XXZ-自旋链中的阈值奇异点
Threshold singularities in the XXZ- spin chain
论文作者
论文摘要
我们计算较低阈值的XXZ-Spin链的光谱密度的阈值奇点的临界指数。我们表明，相应的相移是不依赖动量的，并与有效的移动杂质哈密顿方法的预测共同进行。我们表明，对于具有高能粒子的特征状态，具有动量$ k $的特征状态，它比粒子孔刺激的动量大得多，即使在限制$ k << p_f $中，在Luttinger模型的框架中也没有描述FormFactor，但应在有效的移动移动杂质Hamilton方法的框架中评估。
We calculate the critical exponents of the threshold singularity for the spectral density of the XXZ- spin chain at zero magnetic field for the lower threshold. We show that the corresponding phase shifts are momentum-independent and coinside with the predictions of the effective mobile impurity Hamiltonian approach. We show that for the eigenstates with the high-energy particle with the momentum $k$ which is much larger than the momenta of the particle-hole excitations the formfactor is not described in the framework of the Luttinger model even in the limit $k<<p_F$ but should be evaluated in the framework of the effective mobile impurity Hamiltonian approach.
