In Situ Probing of Correlations and Dynamics with Quantum Gases in Optical Lattices

在这个项目中，芝加哥大学（University of Chicago）秦博士的团队识别并研究了在超低温下强相互作用原子的一般行为。一旦确定了这些一般的相关性，我们对自然界中其他一类复杂量子系统的理解将大大提高。一个突出的目标是理解高tc超导性，其中基本的微观相互作用可能被光学晶格中的费米子原子捕获。另一个令人着迷的目标是探索“量子相变”附近原子动力学与弦理论描述的早期宇宙中的量子引力之间的推测对应关系。总体而言，该项目将确定量子系统在强耦合状态下出现的普遍行为。更具体地说，基于高空间分辨率锂铯量子气体的原位成像，研究了所有长度尺度上的时空密度相关性。空间相关性可以从同期密度测量中提取，而时间相关性则通过局部戳戳样品并监测随之而来的密度响应来测量。在其他方向上，该小组研究了费米-哈伯德模型描述的晶格中费米子的配对和超流动性，量子临界输运，以及它与推测的量规-重力二象性的联系。粒子的相关性是凝聚态物理和材料科学研究的基本兴趣，因为它们是新量子现象的核心，如高tc超导和量子磁性。两者都对我们对量子材料的理解构成了重大挑战。近年来，基于超冷原子的量子模拟已成为揭示复杂量子现象奥秘的有力工具和快速发展的研究方向。最后，该组织正在为历史悠久的芝加哥南部公立学校的K-12学生发起一项新的推广计划。该项目提供了丰富多彩的科学教育活动，以增强青年学生对现代科学技术发展的了解。

In this project, Dr. Chin's group at the University of Chicago identifies and investigates generic behaviors of strongly interacting atoms at ultralow temperatures. Once these generic correlations are determined, our understanding of a whole class of other complex quantum systems in nature will be greatly improved. One prominent goal is to understand high-Tc superconductivity, where the essential microscopic interactions can potentially be captured by fermionic atoms in optical lattices. Another fascinating goal is to explore the conjectured correspondence between the dynamics of atoms near a "quantum phase transition" and the quantum gravity in the early universe described by string theory.Overall, the project will identify emerging universal behaviors of quantum systems in the strong coupling regime. More specifically, temporal and spatial density correlations at all length scales are being investigated based on in situ imaging of Lithium-Cesium quantum gases with high spatial resolution. Spatial correlations can be extracted from same-time density measurement, while temporal correlations are being measured by locally poking the sample and monitoring the consequent density response. Among other directions, the group investigates pairing and superfluidity of fermions in lattices described by the Fermi-Hubbard model, and quantum critical transport, and its connection to the conjectured gauge-gravity duality.Correlations of particles are of fundamental interest in the research of condensed matter physics and materials science, since they lie at the heart of novel quantum phenomena, such as high-Tc superconductivity and quantum magnetism. Both pose a major challenge to our understanding of quantum materials. In recent years, quantum simulations based on ultracold atoms has emerged as a powerful tool and a fast growing research direction for unveiling the mystery of complex quantum phenomena.Finally, the group is initiating a new outreach program for K-12 students of public schools in the historical Chicago south side. This program offers a variety of science education activities to enhance the exposure of young students to the development of modern science and technology.