We consider a disordered Hubbard model and show that, at sufficiently weak disorder, a single spin-down mobile impurity can thermalize an extensive initially localized system of spin-up particles. Thermalization is enabled by resonant processes that involve correlated hops of the impurity and localized particles. This effect indicates that Anderson localized insulators behave as “supercooled” systems, with mobile impurities acting as ergodic seeds. We provide analytical estimates, supported by numerical exact diagonalization, showing how the critical disorder strength for such mechanism depends on the particle density of the localized system. In the $U\to \infty$ limit, doublons are stable excitations, and they can thermalize mesoscopic systems by a similar mechanism. The emergence of an additional conservation law leads to an eventual localization of doublons. Our predictions apply to fermionic and bosonic systems and are readily accessible in ongoing experiments simulating synthetic quantum lattices with tunable disorder.

中文翻译：

---

过冷绝缘子中单个移动杂质对遍历核的核化

我们考虑了无序的Hubbard模型，并表明，在足够弱的无序状态下，单个旋转向下的移动杂质可以使旋转向上的粒子的广泛初始局部系统热化。通过涉及杂质和局部粒子的相关跃点的共振过程可以实现热化。该效果表明，安德森局部绝缘子的行为类似于“过冷”系统，而可移动杂质充当遍历种子。我们提供了精确的对角线化支持的分析估计，显示了这种机制的关键无序强度如何取决于局部系统的粒子密度。在里面$ü\to \infty$极限，双链是稳定的激发，它们可以通过类似的机制使介观系统热化。额外的保护法的出现导致了双子的最终定位。我们的预测适用于费米子和玻色子系统，并且在正在进行的模拟具有可调性无序的合成量子晶格的实验中很容易获得。