论文标题
基塔夫模型中的热增强Majorana介导的自旋传输
Thermally enhanced Majorana-mediated spin transport in the Kitaev model
论文作者
论文摘要
我们研究了量子自旋kitaev模型中主要介导的自旋转运的稳定性是针对热波动的。使用时间依赖性的热量子态法，我们检查了Kitaev模型中的有限温度自旋动力学。该型号分别显示出两个特征温度$ t_l $和$ t_h $，它们分别对应于当地通量和巡回少Majorafana fermion的能量尺度。在低温$（t \ ll t_l）$下，实现了几乎无通量的状态，并且旋转激发以与基态相似的方式传播。也就是说，在其中一个边缘引入磁脉冲后，即使通过量子自旋液态状态区域，流动的Majorana fermions也会传播自旋激发，并且旋转力矩的振荡出现在另一个边缘，带有微小的磁场。当$ t \ sim t_l $时，与基态的结果相比，在另一个边缘诱导旋转力矩中的较大振荡。在较高的温度下，激发$ z_2 $通量会干扰流动马利亚纳植物的连贯运动，从而抑制了旋转传播。我们的结果表明，热波动在主要介导的自旋转运中的至关重要。
We study how stable the Majorana-mediated spin transport in a quantum spin Kitaev model is against thermal fluctuations. Using the time-dependent thermal pure quantum state method, we examine finite-temperature spin dynamics in the Kitaev model. The model exhibits two characteristic temperatures $T_L$ and $T_H$, which correspond to energy scales of the local flux and the itinerant Majorana fermion, respectively. At low temperatures $(T\ll T_L)$, an almost flux-free state is realized and the spin excitation propagates in a similar way to that for the ground state. Namely, after the magnetic pulse is introduced at one of the edges, the itinerant Majorana fermions propagate the spin excitations even through the quantum spin liquid state region, and oscillations in the spin moment appear in the other edge with a tiny magnetic field. When $T\sim T_L$, larger oscillations in the spin moments are induced in the other edge, compared to the results at the ground state. At higher temperatures, excited $Z_2$ fluxes disturb the coherent motion of the itinerant Majorana fermions, which suppresses the spin propagation. Our results demonstrate a crucial role of thermal fluctuations in the Majorana-mediated spin transport.
