Observation of spatially ordered structures in a two-dimensional Rydberg gas
Observation of spatially ordered structures in a two-dimensional Rydberg gas
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DOI：
10.1038/nature11596
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发表时间：
2012-11-01
期刊：
影响因子：
64.8
通讯作者：
Bloch, Immanuel
中科院分区：
文献类型：
--
作者：
Schauss, Peter;Cheneau, Marc;Bloch, Immanuel
控制和调节超冷原子气体中相互作用的能力为实现新的物质相铺平了道路。到目前为止，实验已经实现了对短程相互作用的高度控制，但实现长程相互作用已成为研究的中心焦点，因为它将开辟多体物理的新领域。里德堡原子非常适合这个目标，因为它们之间的范德华力比基态原子之间的范德华力大许多个数量级(1)。因此，当原子转移到里德堡态时，仅仅是激光激发超冷气体就可以直接产生强关联的多体态。一个关键的例子是由不同的、空间有序的集体激发组态的相干叠加组成的量子晶体(2-5)。在这里，我们使用高分辨率的原位里德堡原子成像来直接测量激光激发的二维原子Mott绝缘体中的强关联(6)。观测显示，在准备好的多体状态的高密度分量中，出现了具有随机取向但几何结构明确的空间有序激发图案。结合时间分辨分析，这支持了用整个气体中集体激发的离域关联量子态来描述系统。我们的实验证明了里德堡气体实现物质奇异相的潜力，从而为量子磁铁的长程相互作用的量子模拟奠定了基础。
The ability to control and tune interactions in ultracold atomic gases has paved the way for the realization of new phases of matter. So far, experiments have achieved a high degree of control over short-range interactions, but the realization of long-range interactions has become a central focus of research because it would open up a new realm of many-body physics. Rydberg atoms are highly suited to this goal because the van der Waals forces between them are many orders of magnitude larger than those between ground-state atoms(1). Consequently, mere laser excitation of ultracold gases can cause strongly correlated many-body states to emerge directly when atoms are transferred to Rydberg states. A key example is a quantum crystal composed of coherent superpositions of different, spatially ordered configurations of collective excitations(2-5). Here we use high-resolution, in situ Rydberg atom imaging to measure directly strong correlations in a laser-excited, two-dimensional atomic Mott insulator(6). The observations reveal the emergence of spatially ordered excitation patterns with random orientation, but well-defined geometry, in the high-density components of the prepared many-body state. Together with a time-resolved analysis, this supports the description of the system in terms of a correlated quantum state of collective excitations delocalized throughout the gas. Our experiment demonstrates the potential of Rydberg gases to realize exotic phases of matter, thereby laying the basis for quantum simulations of quantum magnets with long-range interactions.