Spin transport in the XXZ chain at finite temperature and momentum.
Spin transport in the XXZ chain at finite temperature and momentum.
复制标题
有限温度和动量下 XXZ 链中的自旋输运。
DOI：
10.1103/physrevlett.107.250602
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发表时间：
2011
影响因子：
8.6
通讯作者：
W. Brenig
中科院分区：
文献类型：
--
作者：
R. Steinigeweg;W. Brenig
研究了在有限温度和动量条件下自旋为1/2的海森堡链在各向同性点以上的磁化输运中动量的作用。使用数值和分析方法，我们分析了密度和电流的自相关性，并观察到一个有限的区域的布里渊区的扩散动力学低于截止动量，和一个独立的动量和时间的扩散常数，其规模与各向异性成反比。降低温度在很宽的范围内，从无穷大开始，扩散常数被发现强烈增加，而截止扩散动量减少。在截止点以上，动量扩散完全中断。
We investigate the role of momentum for the transport of magnetization in the spin-1/2 Heisenberg chain above the isotropic point at finite temperature and momentum. Using numerical and analytical approaches, we analyze the autocorrelations of density and current and observe a finite region of the Brillouin zone with diffusive dynamics below a cutoff momentum, and a diffusion constant independent of momentum and time, which scales inversely with anisotropy. Lowering the temperature over a wide range, starting from infinity, the diffusion constant is found to increase strongly while the cutoff momentum for diffusion decreases. Above the cutoff momentum diffusion breaks down completely.