论文标题
量子自旋链中准粒子相互作用的动态特征
Dynamical signatures of quasiparticle interactions in quantum spin chains
论文作者
论文摘要
我们研究了在纵向Zeeman场的情况下，抗铁磁旋转$ -1/2 $链的横向动力学敏感性。在无间隙阶段的低磁化状态下，我们表明，纺纱子之间的差距无关的反向散射相互作用会在小动量的两个激发分支之间产生非零的间隙。我们进一步证明了这一差距在引入第二个邻居抗铁磁相互作用时如何变化，并在非相互作用的“ Spinon Gas”的极限下消失。在高磁化机制中，随着Zeeman磁场接近饱和值，我们发现了横向敏感性中两麦克努族结合状态的出现。该结合状态特征概括了在可集成案例的Bethe Ansatz解决方案中引起的弦状态。我们的结果基于数值准确的，无偏的基质 - 产品状态技术以及分析近似。
We study the transverse dynamical susceptibility of an antiferromagnetic spin$-1/2$ chain in presence of a longitudinal Zeeman field. In the low magnetization regime in the gapless phase, we show that the marginally irrelevant backscattering interaction between the spinons creates a non-zero gap between two branches of excitations at small momentum. We further demonstrate how this gap varies upon introducing a second neighbor antiferromagnetic interaction, vanishing in the limit of a non-interacting "spinon gas". In the high magnetization regime, as the Zeeman field approaches the saturation value, we uncover the appearance of two-magnon bound states in the transverse susceptibility. This bound state feature generalizes the one arising from string states in the Bethe ansatz solution of the integrable case. Our results are based on numerically accurate, unbiased matrix-product-state techniques as well as analytic approximations.
