美国普林斯顿大学Waseem S. Bakr研究团队取得一项新突破。他们探明了探测超冷分子自旋系统中的位置分辨相关性。2023年2月1日出版的《自然》发表了这项成果。

课题组利用量子气体显微镜，测量限制在二维光学晶格中的极性²³Na⁸⁷Rb分子的量子相关性的位置分辨动力学。利用两个旋转态，实现了具有粒子间偶极相互作用的自旋1/2系统，产生了量子自旋交换模型。小组研究了空间各向同性和各向异性相互作用的非平衡自旋系统热化过程中相关关系的演化。

此外，小组通过使用周期性微波脉冲，研究了自旋各向异性Heisenberg模型的相关动力学。这些实验是探测和控制超冷分子相互作用系统的前沿，具有探索量子物质新体系和描述纠缠态的前景，这些纠缠态对量子计算和计量学有重要作用。

据了解，具有相互作用成分的合成量子系统在量子信息处理和解释多体物理中的基本现象方面发挥着重要作用。随着冷却和捕获技术的惊人进步，超冷极性分子的集合已经成为一个有前途的平台，它结合了它们的几个优势性质。其中包括大量具有长相干时间的内部态，以及长距离的各向异性相互作用。这些特征可以使相关量子物质的有趣相的探索成为可能，如拓扑超流体，量子自旋液体，分数陈氏绝缘体和量子磁体。探测这些相的相关性对于理解它们的性质至关重要，因此需要开发新的实验技术。

附：英文原文

Title: Probing site-resolved correlations in a spin system of ultracold molecules

Author: Christakis, Lysander, Rosenberg, Jason S., Raj, Ravin, Chi, Sungjae, Morningstar, Alan, Huse, David A., Yan, Zoe Z., Bakr, Waseem S.

Issue&Volume: 2023-02-01

Abstract: Synthetic quantum systems with interacting constituents play an important role in quantum information processing and in explaining fundamental phenomena in many-body physics. Following impressive advances in cooling and trapping techniques, ensembles of ultracold polar molecules have emerged as a promising platform that combines several advantageous properties1,2,3,4,5,6,7,8,9,10,11. These include a large set of internal states with long coherence times12,13,14,15,16,17 and long-range, anisotropic interactions. These features could enable the exploration of intriguing phases of correlated quantum matter, such as topological superfluids18, quantum spin liquids19, fractional Chern insulators20 and quantum magnets21,22. Probing correlations in these phases is crucial to understanding their properties, necessitating the development of new experimental techniques. Here we use quantum gas microscopy23 to measure the site-resolved dynamics of quantum correlations of polar 23Na87Rb molecules confined in a two-dimensional optical lattice. By using two rotational states of the molecules, we realize a spin-1/2 system with dipolar interactions between particles, producing a quantum spin-exchange model21,22,24,25. We study the evolution of correlations during the thermalization process of an out-of-equilibrium spin system for both spatially isotropic and anisotropic interactions. Furthermore, we examine the correlation dynamics of a spin-anisotropic Heisenberg model engineered from the native spin-exchange model by using periodic microwave pulses26,27,28. These experiments push the frontier of probing and controlling interacting systems of ultracold molecules, with prospects for exploring new regimes of quantum matter and characterizing entangled states that are useful for quantum computation29,30 and metrology31.

DOI: 10.1038/s41586-022-05558-4

Source: https://www.nature.com/articles/s41586-022-05558-4