Quantum Slow Relaxation and Metastability due to Dynamical Constraints.
Quantum Slow Relaxation and Metastability due to Dynamical Constraints.
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DOI：
10.1103/physrevlett.121.040603
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发表时间：
2017-06
影响因子：
8.6
通讯作者：
Z. Lan;Merlijn van Horssen;Stephen Powell;J. P. Garrahan
中科院分区：
文献类型：
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作者：
Z. Lan;Merlijn van Horssen;Stephen Powell;J. P. Garrahan
导致经典眼镜的缓慢合作松弛特征的一般机制之一是动力学中存在动力学约束。在这里，我们表明，动态约束类似地导致翻译不变量子多体系统的热量和亚稳定性缓慢。我们通过考虑两个简单的模型来说明这一总体思想：（i）一个对经典晶格气体的一维量子类似物，在这种量子上，激发跳跃受到相邻地点的状态的约束，模仿了密集流体的排除量相互作用； （ii）正方形晶格上的完全包装量子二聚体。这两个模型都有一个Rokhsar-Kivelson（RK）点，该点具有相等的动能和势能常数。在RK点的一侧，动能占主导地位，热化速度很快。在势能占主导地位的另一个情况下，热量缓慢，对初始条件的记忆持续很长时间，而分离时间标准会导致在最终热化之前明显的亚稳定性。此外，与经典眼镜的放松相比，缓慢的热度状态表现出动态异质性，表现为空间隔离的纠缠生长。
One of the general mechanisms that give rise to the slow cooperative relaxation characteristic of classical glasses is the presence of kinetic constraints in the dynamics. Here we show that dynamical constraints can similarly lead to slow thermalization and metastability in translationally invariant quantum many-body systems. We illustrate this general idea by considering two simple models: (i) a one-dimensional quantum analogue to classical constrained lattice gases where excitation hopping is constrained by the state of neighboring sites, mimicking excluded-volume interactions of dense fluids; and (ii) fully packed quantum dimers on the square lattice. Both models have a Rokhsar-Kivelson (RK) point at which kinetic and potential energy constants are equal. To one side of the RK point, where kinetic energy dominates, thermalization is fast. To the other, where potential energy dominates, thermalization is slow, memory of initial conditions persists for long times, and separation of timescales leads to pronounced metastability before eventual thermalization. Furthermore, in analogy with what occurs in the relaxation of classical glasses, the slow-thermalization regime displays dynamical heterogeneity as manifested by spatially segregated growth of entanglement.