Parametric instabilities in resonantly-driven Bose–Einstein condensates
Parametric instabilities in resonantly-driven Bose–Einstein condensates
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DOI：
10.1088/2058-9565/aab2b9
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发表时间：
2017-11
影响因子：
6.7
通讯作者：
S. Lellouch;S. Lellouch;N. Goldman
中科院分区：
文献类型：
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作者：
S. Lellouch;S. Lellouch;N. Goldman
以共振方式振动光学晶格为超冷原子气体设计人工规范场和拓扑能带结构提供了一种有效而通用的方法。这一点最近通过实验实现了Harper-Hofstadter模型，该模型结合了光学超晶格和共振时间调制。将粒子间相互作用添加到这些工程能带系统中，预计将导致具有拓扑特征的强关联态，例如分数陈氏绝缘体。然而，相互作用和外部时间周期驱动之间的相互作用通常会引发剧烈的不稳定性和无法控制的加热，因此可能排除在实验中获得这种有趣的物质状态的可能性。在这项工作中，我们研究的早期阶段的参数不稳定性，发生在系统的共振驱动玻色-爱因斯坦凝聚在光学晶格。我们将基于Bogoliubov理论的方法（Lellouch et al 2017 Phys. Rev. X 7 021015）应用并扩展到各种共振驱动带模型，从简单的振动Wannier-Stark阶梯到更有趣的驱动诱导Harper-Hofstadter模型。特别是，我们提供从头算的数值和分析预测这些专题模型的稳定性。这项工作揭示了一般功能，可以指导目前的实验稳定的操作制度。
Shaking optical lattices in a resonant manner offers an efficient and versatile method to devise artificial gauge fields and topological band structures for ultracold atomic gases. This was recently demonstrated through the experimental realization of the Harper–Hofstadter model, which combined optical superlattices and resonant time-modulations. Adding inter-particle interactions to these engineered band systems is expected to lead to strongly-correlated states with topological features, such as fractional Chern insulators. However, the interplay between interactions and external time-periodic drives typically triggers violent instabilities and uncontrollable heating, hence potentially ruling out the possibility of accessing such intriguing states of matter in experiments. In this work, we study the early-stage parametric instabilities that occur in systems of resonantly-driven Bose–Einstein condensates in optical lattices. We apply and extend an approach based on Bogoliubov theory (Lellouch et al 2017 Phys. Rev. X 7 021015) to a variety of resonantly-driven band models, from a simple shaken Wannier–Stark ladder to the more intriguing driven-induced Harper–Hofstadter model. In particular, we provide ab initio numerical and analytical predictions for the stability properties of these topical models. This work sheds light on general features that could guide current experiments to stable regimes of operation.