论文标题
在扰动的各向同性海森堡自旋链中的自旋扩散
Spin diffusion in perturbed isotropic Heisenberg spin chain
论文作者
论文摘要
各向同性的海森堡链代表了一种在有限温度下表现出超级旋转传输的可集成多体系统的特殊情况。在这里，我们表明该模型在有限磁化$ m \ ne0 $上也具有不同的属性，即使引入了SU（2）不变扰动。具体而言，我们观察到旋转各向异性$δ$的扩散常数$ {\ cal d} _0（δ）$的非单调依赖性，其最大值为$δ= 1 $。后者的依赖性在零磁化领域也保持不变，超级扩散为$δ= 1 $，这对于各向同性扰动（至少在有限大小的系统中）非常稳定，这与最近的冷原子实验一致。
The isotropic Heisenberg chain represents a particular case of an integrable many-body system exhibiting superdiffusive spin transport at finite temperatures. Here, we show that this model has distinct properties also at finite magnetization $m\ne0$, even upon introducing the SU(2) invariant perturbations. Specifically, we observe nonmonotonic dependence of the diffusion constant ${\cal D}_0(Δ)$ on the spin anisotropy $Δ$, with a pronounced maximum at $Δ=1$. The latter dependence remains true also in the zero magnetization sector, with superdiffusion at $Δ=1$ that is remarkably stable against isotropic perturbation (at least in finite-size systems), consistent with recent experiments with cold atoms.
