标题： 粒子配对导致不平衡Hubbard模型中重粒子的亚扩散 显示英文标题

标题： Particle pairing causes subdiffusion of heavy particles in the imbalanced Hubbard model

摘要： 不平衡的Hubbard模型在不同粒子种类之间的质量比和耦合强度变化时表现出动态区域之间的转变。 轻粒子输运的减缓可以归因于在高质量比和强耦合下，重粒子引起的有效无序效应。 这个亚扩散区域被解释为Griffiths相，将这种效应与金属区和绝缘区的共存联系起来。 在这里，我们研究重粒子的动力学，这也显示出亚扩散行为，但无法用Griffiths图像来解释。 我们证明，在动力学过程中，重粒子主要形成小团簇，主要是成对出现，这降低了它们的传播速度，并在较晚的时间将时间依赖的扩散常数暂时转移到亚扩散区域。 驱动这一过程所需的粒子间吸引力可以在Born-Oppenheimer近似中得到理解。 我们引入了一个经典的一维随机行走模型，可以在强耦合区域定量地再现亚扩散动力学。 显示英文摘要

摘要： The imbalanced Hubbard model features a transition between dynamic regimes depending on the mass ratio and coupling strength between two different particle species. A slowdown of the lighter particle transport can be attributed to an emergent effective disorder induced by the heavy particles for high mass ratio and strong coupling. This subdiffusive regime has been interpreted as a Griffiths phase, linking the effect to the coexistence of metallic and insulating regions. Here, we investigate the dynamics of the heavy particles, which also reveals subdiffusive behavior, yet cannot be explained within the Griffiths picture. We demonstrate that heavy particles predominantly form small clusters, mainly pairs, during the dynamical process, which reduces their propagation speed and transiently shifts the time-dependent diffusion constant into the subdiffusive regime at late times. The necessary attraction between particles driving this process can be understood within the Born-Oppenheimer approximation. We introduce a classical one-dimensional random walk model that can quantitatively reproduce the subdiffusion dynamics in the strong coupling regime.