Detection and characterization of many-body localization in central spin models
Detection and characterization of many-body localization in central spin models
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DOI：
10.1103/physrevb.98.161122
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发表时间：
2018-10-29
影响因子：
3.7
通讯作者：
Trauzettel, Bjoern
中科院分区：
文献类型：
--
作者：
Hetterich, Daniel;Yao, Norman Y.;Trauzettel, Bjoern
我们分析了一个无序的中心自旋模型，其中一个中心自旋与周期性一维（1D）随机场海森堡链中的每个自旋相等地相互作用。如果海森堡链最初是在多体局域（MBL）阶段，我们发现，耦合到中心自旋足以使链的耦合强度的一个很大的范围内的离域。我们计算了该模型的相图，并确定了MBL和遍历相之间的相边界。在局域相内，中心自旋显著提高了对数纠缠增长率及其饱和值。我们将纠缠熵的增加归因于由中心自旋引起的磁化涨落的非广泛增强。最后，我们证明了中心自旋的相关函数可以用来区分MBL和遍历阶段的1D链。因此，我们建议使用的中心自旋作为一个可能的实验探针，以确定MBL相。
We analyze a disordered central spin model, where a central spin interacts equally with each spin in a periodic one-dimensional (1D) random-field Heisenberg chain. If the Heisenberg chain is initially in the many-body localized (MBL) phase, we find that the coupling to the central spin suffices to delocalize the chain for a substantial range of coupling strengths. We calculate the phase diagram of the model and identify the phase boundary between the MBL and ergodic phase. Within the localized phase, the central spin significantly enhances the rate of the logarithmic entanglement growth and its saturation value. We attribute the increase in entanglement entropy to a nonextensive enhancement of magnetization fluctuations induced by the central spin. Finally, we demonstrate that correlation functions of the central spin can be utilized to distinguish between MBL and ergodic phases of the 1D chain. Hence, we propose the use of a central spin as a possible experimental probe to identify the MBL phase.