论文标题
旋转链中的弹道到扩散性过渡，可集成性破裂
Ballistic-to-diffusive transition in spin chains with broken integrability
论文作者
论文摘要
我们研究了由边界驱动的XXZ旋转链中的可集成性弱破裂引起的弹道到扩散的过渡。研究旋转电流密度$ \ MATHCAL J s $的演变是系统尺寸$ l $的函数，我们表明，考虑到边界效应，过渡具有接近XX限制的非平凡通用行为。它由散射长度$ l^*\ propto v^{ - 2} $控制，其中$ v $是集成性破坏术语的强度。在XXZ模型中，相互作用的相互作用控制着瞬态的“准球式”制度在长度上的出现比$ l^*$短得多。该参数较大的机制的特征是对电流的强烈重新归一化，该电流禁止通用缩放，这与XX模型不同。我们的结果基于矩阵产品运算符数值模拟，并同意扰动分析计算。
We study the ballistic-to-diffusive transition induced by the weak breaking of integrability in a boundary-driven XXZ spin-chain. Studying the evolution of the spin current density $\mathcal J^s$ as a function of the system size $L$, we show that, accounting for boundary effects, the transition has a non-trivial universal behavior close to the XX limit. It is controlled by the scattering length $L^*\propto V^{-2}$, where $V$ is the strength of the integrability breaking term. In the XXZ model, the interplay of interactions controls the emergence of a transient "quasi-ballistic" regime at length scales much shorter than $L^*$. This parametrically large regime is characterized by a strong renormalization of the current which forbids a universal scaling, unlike the XX model. Our results are based on Matrix Product Operator numerical simulations and agree with perturbative analytical calculations.
