论文标题

多体二维Aubry-André模型中定位和运输的共存

Coexistence of localization and transport in many-body two-dimensional Aubry-André models

论文作者

Štrkalj, Antonio, Doggen, Elmer V. H., Castelnovo, Claudio

论文摘要

无序和准二体的多体量子系统是否在热力学极限下具有长期寿命的局部阶段一直是最近的激烈争论的主题。尽管在一个维度上存在这种多体局部(MBL)阶段的大量证据,但较高维度的行为仍然是一个开放的难题。例如,在二维无序系统中,有人认为,稀有区域可能通过称为雪崩不稳定性的机制导致整个系统的热化。在准膜系统中,完全没有罕见区域,而假定的多体局部相的命运迄今仍未开发。在这项工作中,我们研究了两个多体化准碘模型的定位属性,这些模型是Aubry-André模型的二维概括。通过研究大型系统的不平衡动力学,我们发现了与随机系统相比之下。此外,我们表明,在研究的准碘模型中出现的弱电势的确定性线支持大规模运输,而整个系统则不会热量化。我们的结果表明,准二体的多体系统具有表现出共存定位和运输特性的显着和反直觉的能力 - 这种现象让人联想到超粘膜的行为。我们的发现具有直接的实验性相关性,例如,可以使用最先进的冷原子系统进行测试。

Whether disordered and quasiperiodic many-body quantum systems host a long-lived localized phase in the thermodynamic limit has been the subject of intense recent debate. While in one dimension substantial evidence for the existence of such a many-body localized (MBL) phase exists, the behavior in higher dimensions remains an open puzzle. In two-dimensional disordered systems, for instance, it has been argued that rare regions may lead to thermalization of the whole system through a mechanism dubbed the avalanche instability. In quasiperiodic systems, rare regions are altogether absent and the fate of a putative many-body localized phase has hitherto remained largely unexplored. In this work, we investigate the localization properties of two many-body quasiperiodic models, which are two-dimensional generalizations of the Aubry-André model. By studying the out-of-equilibrium dynamics of large systems, we find a long-lived MBL phase, in contrast to random systems. Furthermore, we show that deterministic lines of weak potential, which appear in investigated quasiperiodic models, support large-scale transport, while the system as a whole does not thermalize. Our results demonstrate that quasiperiodic many-body systems have the remarkable and counter-intuitive capability of exhibiting coexisting localization and transport properties - a phenomenon reminiscent of the behavior of supersolids. Our findings are of direct experimental relevance and can be tested, for instance, using state-of-the-art cold atomic systems.

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